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Poultry processing establishments use antimicrobial aids on broiler parts to minimize Campylobacter contamination. A silver-stabilized hydrogen peroxide (SHP) product was assessed for use as an antimicrobial processing aid. In a series of experiments, wing segments with skin were inoculated with 103 to 107 cells of Campylobacter coli, followed by treatment with SHP at 15,000 or 30,000 mg/L, peroxyacetic acid (PAA) at 300 or 3,000 mg/L (parts per million), or water. Each treatment was applied by either dip or spray. Rinsates from each wing segment were analyzed for direct counts and prevalence of Campylobacter. Treatment with SHP or PAA significantly reduced Campylobacter levels compared with water controls by up to 2.22 log CFU/mL. At high inoculum levels (106 to 107), SHP and PAA applied by dip had up to 1.27 log CFU/mL further reductions of Campylobacter levels compared with spray-treated wing segments. Additionally, wing drumettes were observed to retain higher levels and prevalence of Campylobacter recovery compared with wing flats at a low inoculation level (103). The results indicated that there was no carryover effect of SHP (same day versus 24 h) and dip treatment with SHP or PAA decreased Campylobacter recovery on broiler chicken wing segments compared with a water control. Although a 2-log reduction was modest, SHP had similar efficacy as the commonly used processing aid PAA. SHP shows potential for further investigation as an antimicrobial processing aid for use on poultry parts. HIGHLIGHTS

Summary Euthanasia of large poultry can be particularly challenging due to the difficulty of manual cervical dislocation of large older birds. Euthanasia is intended to swiftly render the animal unconscious and rapidly lead to death using humane methods. Euthanasia by a single operator can be challenging when euthanizing mature broiler breeders and turkeys weighing from 4 to 30 Kg. Owing to the difficulty of manual cervical dislocation on large poultry, development and assessment of alternative methods for euthanasia are necessary. Four American Veterinary Medical Association approved alternative euthanasia methods including mechanical cervical dislocation, nonpenetrative captive bolt, carbon dioxide, and electrical euthanasia were evaluated on broiler breeders, Beltsville Small White turkeys, and Broad Breasted White turkeys. A mobile bird euthanasia apparatus was designed allowing for individual bird euthanasia by a single operator. Mechanical cervical dislocation and nonpenetrative captive bolt devices were commercially available. The carbon dioxide and electrical euthanasia devices used were developed for this work. Each of the 4 euthanasia methods were assessed for kill success defined as one euthanasia attempt with no signs of recovery. In addition, the costs associated with purchase or construction of each device are reported. All four euthanasia methods resulted in successful euthanasia of 436 birds. The overall single application euthanasia success rates were 97% for mechanical cervical dislocation, 98% for captive bolt, 97% for carbon dioxide, and 99% for electrical euthanasia. Each method can be used to successfully euthanize broiler breeders and turkeys and can be used safely when the use of manual cervical dislocation is not feasible.

Dust present in poultry houses can disseminate bacteria in air and deposit them on surfaces. This study evaluated bacteria in settled dust during growout of broilers from 2 flocks (Flocks A and B). Dust samples for bacteria analyses were obtained during 6 wk of growout (Flocks A and B) and 1 wk after flock termination (Flock B) by environmental swabbing and collecting dust in petri dishes from multiple locations inside the poultry house. For weekly swabbing, dust deposited during each wk of the sampling period (noncumulatively, n = 12/wk) and cumulatively (n = 12/wk) throughout the sampling period was collected. Swabbed dust samples were analyzed for counts (log10 CFU/28 cm2) of aerobic bacteria, E. coli, coliforms, and Salmonella recovery. For petri dish dust collection, dust was collected in weekly and bi-weekly time spans during the sampling period and then analyzed for Salmonella recovery. Data were analyzed by one-way ANOVA and Fisher's Exact Test and means were separated using LSD. Only aerobic plate counts changed over time in dust during growout (Flocks A and B; P < 0.0001). In noncumulatively settled dust, aerobic bacteria (Flocks A and B; P < 0.0001), E. coli (Flock A; P = 0.0432), and coliforms (Flock B; P = 0.0303) varied during growout with peak counts on wk 5 or wk 6, wk 4, and wk 4, respectively, after bird placement. Salmonella recovery did not vary in cumulatively (3/72, 10/84) and noncumulatively (0/12, 10/84) settled dust during growout in both flocks. In dust sampled by bi-weekly collection in petri dishes, Salmonella recovery was highest (5/6) between wk 2 to wk 4 for Flock B (P = 0.0118). Overall, this study displayed that settled dust bacteria levels can fluctuate during broiler growout, and dust can contain Salmonella.

Summary: Litter sampling is utilized as a noninvasive and practical method to determine broiler flock Salmonella status. The common methods include boot cover/sock (BC), drag swab (DS), or litter grab sampling (LG). Roller swabs are a new research method that can be used to sample litter without entering research pens. This study aimed to assess the use of roller swabs (RS) for Salmonella (S) detection in comparison to BC, DS, and LG. For Experiment 1, litter was sampled for two weeks following a broiler flock that was challenged at 6 days of age with 1 × 107cfu of a nalidixic acid resistant strain of Salmonella Enteritidis to establish a high litter prevalence of S. In Experiment 2, sampling occurred after a subsequent flock was raised on the same litter. In Experiment 1, S was detected by RS less frequently (81%) than DS (95%), BC (97%), and LG (98%; P < 0.0001). In Experiment 2, S detection using RS (23%) was similar to LG (17%), higher than DS (6%, P = 0.022), and lower than BC (55%, P < 0.0001). Although RS were a less sensitive sampling method when the litter prevalence of S was high, RS were equivalent to or better than LG and DS methods when S prevalence was low. The use of roller swabs allows for sampling of litter without entering each pen and has the potential to be utilized for Salmonella detection in research pen trials.

SUMMARY A series of experiments were conducted to measure the effects of adding antimicrobials for 2 d: cetylpyridinium chloride (CPC), hydrogen peroxide (HP), and/or sodium bisulfate (SB) to water drinker lines of market-age broilers on water usage, feed consumption, and inoculated Salmonella retention during feed and water withdrawal. The following experiments were evaluated: Salmonella retention with CPC (Experiment 1), water and feed consumption with CPC (Experiment 2) or with CPC and HP (Experiment 3), Salmonella retention with HP (Experiment 4) or with HP and SB (Experiment 5). For Experiment 1, water usage in the CPC treatment pens was only 14% of control pens and had no impact on Salmonella retention. For Experiments 2 and 3, the water usage by broilers was depressed 40 to 97% compared to controls. For Experiment 4, the number of Salmonella-positive enriched crop samples was significantly lower for 50 ppm HP+ citric acid (CA) pens (17%) compared to control (100%). For Experiment 5, water antimicrobial treatments did not differ significantly in Salmonella recovery from the control for both enriched crops (65%) or ceca (82%). Neither CPC nor SB was determined to be effective intervention against Salmonella when added to drinking water during feed/water withdrawal. In Experiment 4, 50 ppm HP+CA was an effective Salmonella intervention in crops while broilers remain on water during feed withdrawal.

SUMMARY A significant point of entry for Salmonella into a processing plant is within the broilers to be processed. Prior to transport to the processing plant, feed (4 h) and water are withdrawn from the broilers on the farm before they are caught and cooped. During catching, an increased presence of dust in the house air is visible and may affect the presence of bacteria within the broiler’s respiratory tract. The objective of this study was to examine the effect of catching on the levels of aerobic bacteria (aerobic plate count [APC]), levels and prevalence of Enterobacteriaceae (EB), and prevalence of Salmonella within broiler respiratory tracts. To determine flock Salmonella status 1 wk prior to catching, broiler carcasses were sampled for APC, EB, and Salmonella by respiratory tract flushing and ceca were sampled for Salmonella. At 1 d prior to catching and when half of the broilers in the house were caught, broilers were again collected, transported to the pilot plant, euthanized, and sampled. In Trial 1, there were no significant differences between sampling times for ceca Salmonella or respiratory EB and APC. However, Salmonella prevalence in the respiratory tract was significantly higher at 1 wk preharvest compared to during catching. In Trial 2, EB was significantly lower during catching compared to 1 wk preharvest. No significant differences were detected in Trial 3. Based on these results, the presence of aerosolized dust in the broiler house during catching does not appear to lead to increases in broiler respiratory tract microbial contamination.

SUMMARY Three experiments were performed to evaluate scalding tank poultry processing wastewater (PPW) loading following the slaughter and scalding of commercially raised broilers: hard vs. soft scalding protocols (experiment 1), scalding immersion time and temperature individually (experiment 2), and the presence of residual blood (experiment 3). One-liter water samples were taken from each scald tank and analyzed for chemical oxygen demand (COD), total solids (TS), and total suspended solid (TSS) concentrations, which were then used to calculate PPW loading (g/kg broiler live weight). For experiment 1, there was significantly higher PPW loading for soft scald/tank 1 (1.834 g/kglwt) than hard scald/tank 1 (1.510 g/kglwt) protocol for COD. There were no other significant differences between scalding protocols for experiments 1 and 2, but there was a trend that the longer immersion time protocols resulted in PPW higher loading for all 3 analytics. For all 3 experiments, the use of sequential scalder tanks significantly reduced PPW loading for both organic and solid materials (COD, TS, and TSS) with tank 1 being significantly higher (50 to 89%) than tanks 2 and 3. Residual blood following a 120 s bleed time did not impact PPW loading compared to non-bled carcasses. These results indicate that scalder immersion time appears to be major indicator for predicting PPW loading in scalders and shows decreases with each sequential scald tank.

The impact of restrictive feeding programs on Salmonella and Campylobacter colonization and persistence after challenge was investigated for broiler breeder pullets housed in an experimental rearing facility. Pullet-chicks were placed on litter in 3 feeding program rooms and each room contained 2 replicate pens. The feeding programs were: (1) Skip-a-day in trough feeders (SAD); (2) Every-day in trough feeders (EDT); (3) Every-day on the pen litter (EDL). On d 1, an additional group of hatchmate chicks were housed in a separate room and gavaged with Salmonella Typhimurium, to later serve as seeder chicks. After seeders were confirmed Salmonella-positive at wk 4, at wk 5 seeders were placed into each feeding program pen to commingle with 135 penmates. At 7, 9, 11, 17, 18, and 20 wk the litter surface in each pen was sampled using intermittently stepped-on drag-swabs. At 8, 12, 16, and 20 wk of age the ceca were sampled from 10 penmates/pen and 2 pooled spleen samples/pen were collected. SAD litter remained Salmonella-positive through 20 wk of age while EDL and EDT pens had no detectible litter Salmonella recovery by 18 and 20 wk. EDL fed pens had no direct (102 cfu/mL) litter Salmonella recovery during the entirety of the experiment. Salmonella prevalence for ceca from SAD pullets was significantly (P0.05) higher at 8 wk (70%) compared to EDT (40%) and EDL (30%). At wk 12, SAD pullets for both on and off-feed sampling days had significantly higher Salmonella recovery (40%), compared to EDT and EDL (both at 5% recovery). By 16 and 20 wk, only the SAD pullets on the on-feed day (48 h without feed) had recovery of Salmonella at 20%. Salmonella recovery in pooled spleen samples did not appear associated with feeding treatments (22% positive). The remaining pullets challenged with Campylobacter at 21 wk produced similar trends as was seen for Salmonella. SAD program pullets had significantly higher Campylobacter from ceca (80 to 100%) compared to pullets on EDL (30 to 60%) or EDT (40 to 95%). These results suggest that using a Skip-a-Day feeding program for broiler breeder pullets contributes to persistently higher Salmonella and Campylobacter ceca colonization and litter prevalence.

Dust present in poultry houses can contain high concentrations of microorganisms and has the potential to include pathogens from the litter. The objective of this study was to examine in vitro the potential for litter to dust transfer of aerobic bacteria, Salmonella, E. coli, and coliforms, and the role of the litter moisture on this process. Poultry litter was inoculated with 102 to 109 CFU/mL of Salmonella Typhimurium to evaluate litter to dust transfer of bacteria (Experiment 1). To evaluate the effect of litter moisture on litter to dust microbial transfer (Experiment 2), litter was inoculated with 109 S. Typhimurium with increasing amounts of sterilized water added for moisture adjustment. Dust was generated by blowing air in a direct stream onto inoculated litter while simultaneously collecting dust through impingement. Following litter and dust sample collection, microbial analyses for aerobic plate counts (APC), Salmonella, E. coli, and coliforms were conducted. Both experiments were repeated 5 times and their data analyzed by one-way ANOVA and simple logistic regression. In Experiment 1, APC of litter (log10 CFU/g) and dust samples (log10 CFU/L) were 10.55 and 4.92, respectively. Salmonella ranged from 1.70 to 6.16 log10 CFU/g in litter and only one dust sample had 1.10 log10 CFU/L of Salmonella. As Salmonella levels in litter increased, the probability of obtaining a dust Salmonella positive result also increased. In Experiment 2, attained moisture percentages were 13.0, 18.2, 23.0, 28.2, and 33.3%. Litter recovery for APC, Salmonella, E. coli, and coliforms counts did not differ (P > 0.05) with increasing moisture levels. Dust sample bacterial counts significantly decreased with increasing moisture levels (P < 0.0001). Results from this in vitro study indicate that there is potential for Salmonella to be present in generated dust and the higher levels of Salmonella in litter increase the likelihood of detecting Salmonella in dust. Additionally, with higher litter moisture percentage, prevalence of Salmonella in generated dust was decreased.

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmonella Heidelberg. Three d post challenge, a 12-hour feed withdrawal was initiated, and one pen of broilers was switched between rooms for each Salmonella serotype. In experiments 3 and 4, non-challenged broilers also were added to the Salmonella challenge pens. The litter of each pen was sampled before and after the feed withdrawal period, the broilers euthanized, and the crop and ceca aseptically removed for Salmonella isolation. Results showed that only the challenge Salmonella serotype was recovered from the litter in challenge pens where broilers were not moved, while both Salmonella serotypes were recovered from the litter of the switched pens. Salmonella was recovered from 56/80 crops and from 66/80 ceca of challenged broilers that remained in the challenge pens. The challenge Salmonella serotype was recovered from 50/80 crops and from 60/80 ceca, and the switched pens' litter Salmonella serotype was recovered from 19/80 crops but not from the ceca in broilers challenged with Salmonella and then switched between pens. For experiments 3 and 4, Salmonella was recovered from 19/40 crops and from only 2/40 ceca from the non-challenged broilers placed into the Salmonella challenge pens. The results from broilers that were switched between Salmonella challenge pens indicate that the recovery of Salmonella from the crop of broilers following feed withdrawal (on Salmonella-contaminated litter) appears to depend mainly on the initial challenge Salmonella (62%) and less on the litter Salmonella (24%) status during the feed withdrawal period. In contrast, only the initial challenge Salmonella was recovered from the ceca (79%) from broilers that remained in challenge pens or were switched between Salmonella challenge pens. However, when non-challenged broilers were placed into the Salmonella challenge pens and commingled during the 12-hour feed and water withdrawal period, it was possible to recover the pen litter Salmonella from the ceca at a low level of 5% (2/40).

SUMMARY Pre-cooked chicken meat products provide convenience to consumers and are growing in popularity globally. Poultry meat destined for pre-cooked meat products typically undergoes chilling on the carcass skeletal frame and deboning before cooking. However, cooking products directly without prior carcass chilling has the potential to reduce energy costs and more effectively destroy microorganisms. The objective of this study was to compare the use of non-chilled chicken fillets (either hot-boned or left intact on carcasses) to chilled fillets for pre-cooked products. Broiler carcasses were collected from the processing line immediately after evisceration. Fillets were either deboned or left intact on carcasses and cooked either directly without prior carcass chilling or deboned and cooked immediately after chilling. The tenderness of cooked products was estimated with the blunt Meullenet-Owens Razor Shear test. Results showed no difference (P > 0.05) in shear measurements between cooked non-chilled fillets and cooked chilled fillets regardless of deboning. Leaving fillets intact on carcasses during cooking resulted in lower shear values compared to deboned fillets regardless of chilling. There were no significant differences (P > 0.05) in cook yield between non-chilled fillets and chilled fillets. These results demonstrate that compared to chilled fillets, non-chilled fillets can be used for pre-cooked chicken breast meat in commercial practice without adverse effects on meat tenderness or cook yield. Fillets left intact on carcasses during cooking significantly improves shear of finished products.

Salmonella and Campylobacter are frequent colonizers of the intestinal tracts of poultry and have often been associated with human foodborne illness. The entry, transmission, and prevalence of both pathogens have been extensively studied in chickens but little information is available for turkeys. This project monitored turkey breeder hens and toms from d of hatch to 65 wk of age with the objective of determining routes of transmission for Salmonella and Campylobacter throughout the turkey production cycle. Breeder poults were separated by sex and then into 2 groups (control and inoculated) for each sex. The inoculated group was orally gavaged with marker strains of both Salmonella and Campylobacter. The inoculated groups (toms and hens) were placed on the opposite side of a growout house from the uninoculated groups. Fecal samples, intestinal samples and organs, feed, drinkers, and potential vectors such as insects and mice, were analyzed at different times until 65 wk. Monitoring showed that Campylobacter spread rapidly and cross-contaminated turkeys throughout the growout house. For both Salmonella and Campylobacter, naturally occurring strains that were first isolated in control groups at wk 3 and 4, respectively, outcompeted marker strains several wk post inoculation and persisted in the flock. The most common naturally occurring strains were C. jejuni (tetracycline resistant), C. coli (kanamycin resistant), and S. Agona. Campylobacter and Salmonella also were isolated from flies and from a mouse, confirming the importance of proper pest control and biosecurity to reduce the spread of the bacteria.

The housing of laying hens is important for social, industrial, and regulatory aspects. Many studies have compared hen housing systems on the research farm, but few have fully examined commercial housing systems and management strategies. The current study compared hens housed in commercial cage-free aviary, conventional cage, and enriched colony cage systems. Environmental and eggshell pool samples were collected from selected cages/segments of the housing systems throughout the production cycle and monitored for Salmonella and Campylobacter prevalence. At 77 wk of age, 120 hens per housing system were examined for Salmonella and Campylobacter colonization in the: adrenal glands, spleen, ceca, follicles, and upper reproductive tract. All isolates detected from environmental swabs, eggshell pools, and tissues were identified for serotype. Two predominant Salmonella were detected in all samples:S.Braenderup andS.Kentucky.Campylobacter coli and C. jejuni were the only Campylobacter detected in the flocks. Across all housing systems, approximately 7% of hens were colonized with Salmonella, whereas >90% were colonized with Campylobacter Salmonella Braenderup was the isolate most frequently detected in environmental swabs (P

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89–100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0–41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety.

Three separate broiler Salmonella Typhimurium challenge experiments were conducted evaluating efficacy of formic and propionic acid feed supplements to suppress environmental and cecal Salmonella Typhimurium prevalence. In experiment 1, broilers were provided feed with 1 kg/ton formic acid or 5 kg/ton propionic acid feed additives or a basal control diet. At the day of placement, half of the pens were inoculated with seeder chicks orally challenged with a marker strain of Salmonella Typhimurium and to yield challenged and adjacent nonchallenged pens. No differences in weekly litter samples or cecal Salmonella prevalence at 3 or 6 wk among feeding treatments were detected. In experiment 2, treatments were: 2 kg/ton propionic acid in feed, 1.0 mL/L formic acid in water, both propionic acid in feed and formic acid in water, and a basal control. Every pen was challenged with seeder chicks inoculated with Salmonella Typhimurium. By 6 wk all pens maintained detectable litter Salmonella, and broilers provided both propionic acid in feed and formic acid in water had the lowest cecal recovery (35%), compared to the control (60%). In experiment 3, treatments were: formic acid at 4 or 6 kg/ton from wk 0 to 6 or for only the last wk, propionic acid at 5 or 10 kg/ton for only the last wk, and a basal control. Each pen was challenged with Salmonella Typhimurium inoculated seeder chicks. By 6 wk, broilers fed formic acid (4 kg/ton) for the entire growout had no Salmonella-positive ceca (0/30). All treatments that provided acid supplemented feed for only the last wk had 3–13% Salmonella-positive ceca. These experiments indicate that adding formic acid to broiler feed appears to prevent Salmonella colonization from challenge pens entering into the adjacent nonchallenge pens. Feeding formic acid (4 kg/ton) for 6 wk resulted in no recovery of Salmonella from ceca compared to the control prevalence of 17%.

The objective of this study was to determine the effects of broiler carcass scalding and chilling methods on meat quality and muscle proteins. During processing, carcasses were hard (60 °C, 1.5 min) or soft (52.8 °C, 3 min) scalded, and either immersion chilled (IC: 0.5 °C, 40 min) or air chilled (AC: 0.5 °C, 120 min). Breast fillets were deboned at 4 h postmortem and used for measuring meat quality and muscle protein characteristics. Scalding by chilling treatment interaction effects on meat quality were not observed. Air chilled carcasses had greater pH 24 , and reduced drip loss and shear force compared to IC carcasses. Cook yield, color ( L * a * b *), and moisture content were not different between chilling treatments. Scalding treatments did not influence quality traits. Sarcoplasmic protein solubility was not influenced by chilling treatment, but was greater in hard versus soft scalded carcasses. Myofibrillar protein solubility was greater in fillets from soft scalded IC carcasses. Alterations in the electrophoretic profiles of the myofibrillar and sarcoplasmic proteins due to treatments indicated minor changes in protein degradation and solubility. Data suggest that while only chilling method influenced meat quality, both scalding and chilling methods influenced protein solubility and degradation in breast fillets deboned 4 h postmortem.

SUMMARY Sanitizing hatching eggs may reduce the chances that a broiler flock will become colonized with Salmonella and reduce the numbers of other microorganisms, such as Enterobacteriaceae, that can depress hatchability. An experiment was conducted to determine if a quaternarybiguanide sanitizer applied as foam or spray would reduce Enterobacteriaceae or Salmonella naturally occurring on broiler hatching eggs. The sanitizer was applied to buggies of 5,040 eggs the day before set (one buggy/treatment at each of 2 settings). Treated eggs were compared with untreated controls. Foam application lowered Enterobacteriaceae prevalence at set (0 vs. 18%) and transfer (5 vs. 28%); spraying was effective only when eggs were set (2.5 vs. 11%). At transfer spray, treated and control eggs were 19% Enterobacteriaceae-positive. Five Salmonella-positives were recorded during the study. No indication that the sanitizer was effective in reducing Salmonella prevalence when applied as foam was observed (3/120 vs. 1/120). No Salmonella were recovered from spray-treated eggs. No statistically significant difference for Salmonella prevalence was noted, but with such a low rate of recovery it is difficult to draw a firm conclusion. However, the sanitizer applied as foam was effective at decreasing the prevalence of Enterobacteriaceae (a family of bacteria that includes Salmonella and Escherichia coli), and is present more often and in higher numbers than Salmonella.

This study compared the recovery of Salmonella from hatching eggs using 3 sampling methods (eggshell rinsing, eggshell crush following a previous rinse, and eggshell crush without previous rinse). Eggshells were drop-inoculated with approximately 10(1), 10(2), or 10(3) cfu/eggshell of Salmonella Enteritidis and allowed to dry at room temperature for 1 or 24 h. For the shell rinse groups, each inoculated egg was rinsed with buffered peptone water. These rinsed eggs were used for the shell crush with previous rinse groups, and each egg was aseptically cracked, the contents discarded, and the eggshell and membranes crushed with buffered peptone water. This same crush procedure was used for the shell crush without previous shell rinse eggs. The recovery of Salmonella 1 h after inoculation for shell rinse sampled eggs was 16% positive at 10(1), 49% at 10(2), and 93% at 10(3) cfu/eggshell challenge. For the shell crush with previous shell rinse, sampled egg recovery was 0% positive at 10(1), 3% at 10(2), and 17% at 10(3) cfu/eggshell. For the shell crush, sampled eggs had recovery of 23% positive at 10(1), 69% at 10(2), and 96% at 10(3) cfu/eggshell challenge. The recovery of Salmonella 24 h after inoculation for the shell rinse eggs was 3% positive at 10(1), 12% at 10(2), and 22% at 10(3) cfu/eggshell challenge; recovery for shell crush with previous shell rinse sampling was 2% positive at 10(1), 8% at 10(2), and 5% at 10(3) cfu/eggshell challenge; and for the shell crush sampling recovery was 2% at 10(1), 32% at 10(2), and 42% at 10(3) cfu/eggshell challenge. Eggshell crush was a more sensitive (∼10 percentage points) sampling method than eggshell rinse at both 1 and 24 h, but both methods were equally optimal when the inoculum was at 10(3) and samples were collected after 1 h. Waiting 24 h after inoculation to sample significantly lowered the recovery for both the shell rinse and shell crush sampling methods by ∼40 percentage points.

SUMMARY Human salmonellosis outbreaks have been linked to contamination of animal feeds. Thus, it is crucial to employ sensitive Salmonella detection methods for animal feeds. Based on a review of the literature, Salmonella sustains acid injury at about pH 4.0 to 5.0. Low pH can also alter the metabolism of Salmonella, hampering the identification process. Because most Salmonella bacteria present in feed and feed ingredients are already stressed by desiccation and heat during conditioning, pelleting, or both, exposure to low pH may kill or severely injure these cells and result in contamination going undetected. Five grams of 7 different feed ingredients and 5 types of feed were added to 45 mL of buffered peptone water (BPW), lactose broth (LB), minimal salts medium (M-9), or universal preenrichment (UP). Media were incubated at 37°C for 18, 24, and 48 h, and the pH of the media was determined. In the case of cereal grains, in general, the initial pH of the preenrichment media ranged from 6.1 to 7.2. Distillers dried grains with solubles in lactose broth was the exception to this trend (pH 4.5). After 18 h of incubation, the pH of the media had decreased to a pH range of 4.0 to 6.1. The preenrichment media behaved in a similar fashion when testing oilseed meals, canola, and soy (i.e., initial pH range was 6.2 to 7.2 and decreased to pH 4.2 to 5.4 for soy and pH 4.4 to 6.0 for canola). With these ingredients, the buffering capacity of BPW, LB, and M-9 was similar. There was more variation in the pH of the preenrichment media among the different poultry feed types. The media from broiler and layer feeds had an initial pH of 6.2 to 7.0, whereas turkey feed was 6.4 to 7.1. After 18 to 48 h incubation in broiler and in layer feed, the pH was 3.9 to 5.6, compared with pH values of 4.5 to 6.8 for turkey feed. For feed, the buffering capacities of BPW, LB, and M-9 were similar. After incubation in commonly used preenrichment media, mixed feeds and feed ingredients can reach a pH that may kill or injure Salmonella. In light of these data, detection methods for Salmonella in feed and feed ingredients may need to be re-evaluated.

SUMMARY Sanitization of broiler hatching eggs provides an opportunity to reduce the eggshell bacterial load entering hatchery incubators, which can be subsequently carried with the chicks to the grow-out farm and ultimately into the processing plant. Two experiments evaluated combination chemicals containing ammonium chlorides (NH4Cl), biguanide (C2H7N5R; BG), bronopol (C3H6BrNO4; BP), quaternary ammonium (NR4), or hydrogen peroxide (H2O2) for efficacy in eliminating inoculated Salmonella from the shell of broiler hatching eggs. These chemicals were compared with no treatment, water sprayed (to account for spray rinsing of eggshells independent of sanitization), and to 1.4% H2O2, a demonstrated effective hatching egg sanitizer for Salmonella. All 4 combination chemicals tested (2NH4Cl+H2O2, 2NR4+BP+BG, 4NR4, and 4NR4+BG) significantly reduced the recovery of Salmonella (80% to 100%) in comparison to the water-sprayed controls (a 9% to 20% reduction following water spray). In the second experiment, the chemical 4NR4+BG (containing 4 quaternary ammoniums and a biguanide) at 200 mg/L was as effective as H2O2 at 1.4% in sanitizing hatching eggs for both Salmonella strains when the inoculum levels were 1 × 10 4 (0% positive) or 1 × 10 6 cfu/eggshell (3% positive). Following hatchability and chick quality trials for 4NR4+BG, this chemical should be considered for evaluation in commercial hatchery operations for the reduction of Salmonella on the shells of hatching eggs.

Campylobacter is an important human pathogen, and consumption of undercooked poultry has been linked to significant human illnesses. To reduce human illness, intervention strategies targeting Campylobacter reduction in poultry are in development. For more than a decade, there has been an ongoing national and international controversy about whether Campylobacter can pass from one generation of poultry to the next via the fertile egg. We recognize that there are numerous sources of Campylobacter entry into flocks of commercial poultry (including egg transmission), yet the environment is often cited as the only source. There has been an abundance of published research globally that refutes this contention, and this article lists and discusses many of them, along with other studies that support environment as the sole or primary source. One must remember that egg passage can mean more than vertical, transovarian transmission. Fecal bacteria, including Campylobacter, can contaminate the shell, shell membranes, and albumen of freshly laid fertile eggs. This contamination is drawn through the shell by temperature differential, aided by the presence of moisture (the "sweating" of the egg); then, when the chick emerges from the egg, it can ingest bacteria such as Campylobacter, become colonized, and spread this contamination to flock mates in the grow house. Improvements in cultural laboratory methods continue to advance our knowledge of the ecology of Campylobacter, and in the not-so-distant future, egg passage will not be a subject continuously debated but will be embraced, thus allowing the development and implementation of more effective intervention strategies.

In each of five sequential trials, laying hens (56-72 wk of age) were challenged with Salmonella and Campylobacter, and 1 wk postinoculation, the challenged hens (n = 3) were commingled with nonchallenged hens (n = 12) in conventional wire cages, on all-wire slats, or on all-shavings floor housing systems. After 12 days, challenged and nonchallenged hens were euthanatized for sample collection. Ceca were aseptically collected from all hens, and the spleen, liver/gallbladder (LGB), lower (LRT) and upper (URT) reproductive tracts, and ovarian follicles (mature and immature) were collected from only the challenged hens after commingling. Samples were divided equally and cultured separately for Salmonella and Campylobacter. Differences in the horizontal transmission of the challenge Salmonella to nonchallenged hens housed in cages (12%), on slats (15%), and on shavings (14%) were not significantly different (P0.05) from the challenged pen-mate hens over the five trials. However, with the inclusion of residual environmental Salmonella, the recovery of Salmonella from nonchallenged hens housed in cages was lowest at 15%, intermediate for hens on slats at 20%, and highest for hens on shavings at 38%. Among challenged hens housed in cages, Salmonella was recovered from only 27% of the cecum and LRT samples. From challenged hens housed on slats, Salmonella was recovered from 38% of the cecum, 12% of the spleen, 19% of the LGB, 44% of the LRT, and 19% of the URT samples. From challenged hens housed on shavings, Salmonella was recovered from 31% of the cecum; 15% of the spleen, LGB, and URT; and 31% of the LRT samples. Horizontal transmission of Campylobacter among nonchallenged pen-mate hens was significantly lower for hens housed in cages at 28% than for hens on shavings at 47%, with hens on slats being intermediate at 36%. For challenged hens housed in cages, Campylobacter was recovered from 27% of the cecum, 13% of the LRT, 7% of the URT, and 17% of the follicle samples. Among the challenged hens housed on slats, Campylobacter was recovered from 44% of the cecum, 6% of the spleen, 19% of the LGB, 12% of the LRT, 6% of the URT, and 14% of the follicle samples. Among challenged hens housed on shavings, Campylobacter was recovered from 46% of the cecum, 8% of the LRT and URT, and 40% of the follicle samples. The overall results of this study indicate that the caged housing system provided the lowest horizontal transmission level of Salmonella and Campylobacter among egg-laying hens.

This study compared surface and deep eggshell aerobic bacteria recovered by the rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of no treatment, water, and 3 sanitizers. The sanitizers were H(2)O(2), phenol, and Q(4)B (a compound chemical containing 4 quaternary ammoniums and 1 biguanide moiety). Eggs were sprayed according to treatment and allowed to dry for 1 h before sampling. To collect samples for the eggshell rinse, each egg was massaged in a plastic bag with 20 mL of saline. Eggshells were then aseptically opened and their contents were discarded before being individually crushed into 50-mL centrifuge tubes containing 20 mL of saline. Aerobic bacteria were enumerated on Petrifilm after 48 h of incubation at 37°C. Aerobic bacteria recovered (log(10) cfu/mL) from the eggshell rinse were highest and similar for the no-treatment (4.0) and water (3.7) groups, lower for the phenol (3.2) and H(2)O(2) (3.1) groups, and lowest for the Q(4)B (2.4) group. Aerobic bacteria levels with the crush-and-rub method were similar for the no-treatment (2.5) and water (2.3) groups, lower for the phenol (1.6) group, intermediate for the H(2)O(2) (1.2) group, and lowest for the Q(4)B (0.9) group. The overall correlation between the rinse and crush-and-rub sampling methods for individual egg aerobic bacteria counts was r = 0.71. The correlation within each treatment revealed the following r values: no treatment, 0.55; water, 0.72; H(2)O(2), 0.67; phenol, 0.73; and Q(4)B, 0.38. A second experiment was designed to further examine the lower aerobic bacterial levels recovered by the crush-and-rub method (for previously rinsed eggs) than the levels recovered in the initial eggshell rinse sample. Eggs were either rinsed and then crushed and rubbed, or they were only crushed and rubbed without a prior rinse. Results confirmed a significant decrease (1.5 log(10) cfu/mL) in bacteria levels between the initial rinse (4.4) and the subsequent crush and rub (2.9) for the same eggshell. For the crush-and-rub eggs with no previous rinsing, the bacteria recovery level (3.9) was not significantly different from levels for the rinse method. Therefore, either the rinse or crush-and-rub sampling methods can be used to recover similar levels of eggshell aerobic bacteria.

Postchill neck skin maceration (NSM) and whole-carcass rinsing (WCR) are frequently used methods to detect salmonellae from processed broilers. These are practical, nondestructive methods, but they are insensitive and may result in false negatives (20 to 40%). Neck skin samples comprise only 4% of the skin from the broiler carcass by weight, while WCR will not detect firmly attached Salmonella organisms and only 7.5% of the rinsate is utilized. Whole-carcass enrichment (WCE) involves incubation of the whole carcass overnight in a preenrichment broth and can recover as few as 8 inoculated Salmonella cells per carcass. The objective of this study was to use NSM, WCR, and WCE sampling to detect naturally occurring Salmonella from the same commercially processed broiler either prechill or postchill. Ten carcasses were obtained prechill and another 10 postchill on each of two replicate days from each of two commercial processing plants. From each carcass, 8.3 g of neck skin was sampled, and then the carcass was rinsed with 400 ml of 1% buffered peptone water. Thirty milliliters was removed and incubated (WCR), and the remaining 370 ml of broth and the carcass were incubated at 37°C for 24 h (WCE). Overall, Salmonella organisms were detected on 21, 24, and 32 of 40 prechill carcasses by NSM, WCR, and WCE, respectively, while 2, 2, and 19 of 40 postchill carcasses were positive by the respective methods. Prechill carcasses were 64% (77 of 120) positive for Salmonella, while postchill carcasses were 19% (23 of 120) positive. Commercial processing reduced the positive-sample prevalence by 45%. Salmonella organisms were detected on 20% (24 of 120) of the samples from plant 1 and 63% (76 of 120) of the carcasses from plant 2. This study demonstrates significant differences in the results for Salmonella prevalence among sampling methods both before and after immersion chilling, as well as between processing plants on days that samples were taken.

Each of the 10 carcasses were rinsed and tested for Campylobacter. Each rinse was subdivided into twelve 25-mL aliquots, without cryoprotectant. Six were stored at 4C and six at −23C. At 4-month intervals, one aliquot from each was streaked onto Campy-Cefex plates and then 5 mL added to 45 mL of Bolton's (B) or 45 mL of Tecra (T) broth; after 48 h at 42C, both enrichments were streaked onto Campy-Cefex plates. At 4 months (4C), 0 of 10, seven of 10 and three of 10 were positive by direct streak, B and T, respectively, while 0 of 10, one of 10 and four of 10 were positive by direct streak, B and T, respectively, at −23C. At 4 months, all 4C samples were negative, while two of 10 frozen samples were positive in both B and T after 8 months and one of 10 in B at 12, 16 and 20 months. Foods contaminated with Campylobacter may still pose a health hazard after long-term freezing. Practical Applications In this study, naturally occurring Campylobacter were able to survive in the rinsate of commercially processed broiler carcasses without the use of a cryoprotectant. The Campylobacter isolate was identified as a nalidixic acid and ciprofloxacin resistant strain of Campylobacter jejuni. Survival and periodic recovery were demonstrated after 20 months of frozen storage in broiler carcass rinsate alone. Therefore, naturally contaminated uncooked frozen poultry may pose a potential health hazard.

SUMMARY Salmonella can penetrate the shells and shell membranes of hatching eggs, and this can critically affect final product contamination levels (processed broiler carcass). There are numerous published studies on the effectiveness of chemical disinfectants for hatching eggs. The purpose of this study was to provide information allowing the reader to accurately assess published works on chemical efficacy to reduce Salmonella on hatching eggs. Three methods of egg inoculation were used: immersion, fecal smear, and droplet. After inoculation, 2 methods of sanitizer application were used: egg immersion (30 s) and spraying (10 s). When an immersion inoculum was used at a high level (107 cells/mL), it was difficult to demonstrate any reduction in Salmonella contamination of eggs with either chemical (hydrogen peroxide or quaternary ammonium), regardless of the application method. When a fecal smear inoculation was used (103 to 107 cells/mL), hydrogen peroxide treatment reduced the number of Salmonella-positive eggs with spray or immersion application; quaternary ammonium was less effective and showed no advantage over water. Droplet inoculation was the mildest of the methods used. With droplet inoculation (105Salmonella cells), immersion and spray application of chemicals resulted in reductions in Salmonella prevalence. In fact, when using the drop inoculation method, slight reductions were noted even when water was used as the treatment. Readers should pay close attention to the method and levels of bacterial inoculation as well as the method of chemical application before deciding on the efficacy of a sanitizing treatment. Experimental methodologies may affect results as much as the chemical composition of the sanitizer being analyzed.

SUMMARY The use of toxic gas mixtures to stun broiler chickens before exsanguination continues to be controversial. This controversy concerns which gas mixture to use, the required structural modifications to the processing plant, and whether the methods are actually more humane than electrical stunning. In response to these criticisms, a system was designed and constructed to produce a controlled atmosphere by using reduced oxygen tension. In all these systems, the birds are rendered unconscious from a lack of oxygen. Low atmospheric pressure is achieved by using controlled slow decompression, which allows the body of the bird to adjust to changes in pressure and thus lose consciousness with minimal discomfort. Advantages include the absence of toxic gases, minimal plant modifications, and the ability to view the birds throughout the process via digital video feed, which can be recorded.

Sampling protocols for detecting Salmonella on poultry differ among various countries. In the United States, the U.S. Department of Agriculture Food Safety and Inspection Service dictates that whole broiler carcasses should be rinsed with 400 ml of 1% buffered peptone water, whereas in the European Union 25-g samples composed of neck skin from three carcasses are evaluated. The purpose of this study was to evaluate a whole carcass rinse (WCR) and a neck skin excision (NS) procedure for Salmonella and Escherichia coli isolation from the same broiler carcass. Carcasses were obtained from three broiler processing plants. The skin around the neck area was aseptically removed and bagged separately from the carcass, and microbiological analysis was performed. The corresponding carcass was bagged and a WCR sample was evaluated. No significant difference (alpha

Effects of spray washing carcasses with Lauric Acid (LA)-Potassium Hydroxide (KOH) on bacteria recovered from Whole-Carcass Rinsates (WCR) were examined. Carcass skin was inoculated with antibiotic resistant strains of Escherichia coli, Salmonella Typhimirum and Campylobacter coli. The first trial examined effects of washing carcasses with water, 0.25% LA-0.125% KOH, 0.50% LA-0.25% KOH, 1.00% LA-0.50% KOH, or 2.00% LA-1.00% KOH at 80 psi for 15 sec. Findings indicated that significantly fewer Total Plate Count (TPC) bacteria, E. coli and Salmonella Typhimirum were recovered from carcasses washed with 2.00% LA-1.00% KOH than from carcasses washed with water and that no C. coli were recovered from carcasses washed with 2.00% LA-1.00% KOH. Another trial examined effects of washing carcasses at 60, 100, or 150 psi of pressure with 2.00% LA-1.00% KOH for 15 sec. Findings indicated that significantly fewer TPC bacteria were recovered from rinsates of carcasses washed with 100 psi than from carcasses washed with 60 or 150 psi. Finally, a trial was conducted to examine effects of washing carcasses for 0, 5, 15, or 30 sec with 2.00% LA-1.00% KOH at 100 psi. Results indicated that significantly fewer bacteria were recovered from carcasses washed for 5 sec than from unwashed carcasses. Furthermore, significantly fewer TPC bacteria and Salmonella Typhimirum were recovered from carcasses washed for 15 sec than for 5 sec and no C. coli were recovered from carcasses washed for 15 or 30 sec. Findings indicate that spray washing carcasses with LA-KOH can affect the number of bacteria recovered from WCR. These studies also provide data that may be useful in designing applications for using of microbicidal surfactants in processin g operations.

Salmonella and Campylobacter are often associated with raw poultry products and continue to be leading causes of food-borne gastroenteritis in the United States. As a result, the presence of these organisms on broiler carcasses is monitored on a routine basis. Abrasive rinsing methods (e.g., adding glass beads) have been shown to increase the level of bacteria recovered from carcasses or carcass parts. The objective of this study was to evaluate the addition of sand to the rinse on bacterial enumeration and the prevalence of Salmonella and Campylobacter recovered from broiler carcasses. During each of 4 replications, 6 prechill and 6 postchill broiler carcasses were collected from a commercial processing plant. All carcasses were split along the dorso-ventral midline. Carcass halves were rinsed in buffered peptone water, whereas the companion half was rinsed in buffered peptone water with sterile sand added. All carcass halves were rinsed for 1 min and the rinsate was collected. Salmonella, coliforms, and Escherichia coli were enumerated and the prevalence of Salmonella and Campylobacter was determined. Salmonella and Campylobacter were isolated from 17 and 50% of the carcass halves, respectively. There was no significant (P > 0.05) difference in Salmonella or Campylobacter prevalence from carcass halves rinsed with or without sand. The addition of sand to the rinse had no effect on the number of Salmonella, coliforms, or E. coli recovered from prechill or postchill carcass halves. These results show that adding sand to the rinse liquid did not improve the recovery of bacteria present on the carcass in either moderate (2.6 log10 cfu/mL rinsate) or low numbers (

The purpose of this study was to compare a conventional culture broth method (Bolton enrichment), a newly developed proprietary broth method (TECRA Campylobacter enrichment), and direct plating for recovery of Campylobacter spp. from chicken carcass rinsates. Whole carcass rinses were taken from 140 carcasses at rehang (immediately after defeathering but before evisceration) and from 140 carcasses at postchill from eight different processing plants in the United States. The rinsate samples were packed in ice and shipped overnight to the laboratory. Aliquots of the rinsate were transferred into Bolton and TECRA enrichment broths and were direct plated. Standard laboratory procedures with Campy-cefex plates were followed for recovery of Campylobacter spp. For rehang carcasses, 94% were positive for Campylobacter spp. with the TECRA enrichment broth and 74% were positive with the Bolton enrichment broth. For postchill carcasses, 74% were positive for Campylobacter spp. with the TECRA enrichment broth and 71% were positive with the Bolton enrichment broth. Compared with the Bolton enrichment broth, TECRA enrichment broth significantly suppressed non-Campylobacter microflora (P < 0.05). Overall, TECRA enrichment broth yielded an 11% higher total number of Campylobacter-positive samples compared with the Bolton enrichment broth. Campylobacter spp. detection in postchill samples was significantly greater (P < 0.05) by enrichment (84%) than by direct plating (19%). The high number of Campylobacter-positive samples obtained with all procedures indicated that 99% of the carcass rinsates obtained at rehang and 84% obtained at postchill contained Campylobacter spp.

The ability of the lesser mealworm, Alphitobius diaperinus (Panzer), commonly known as the darkling beetle, to transmit marker Salmonella Typhimurium to day-of-hatch broiler chicks was evaluated, as well as the spread to nonchallenged pen mates. In trial 1, day-of-hatch chicks were orally gavaged with 4 larval or 4 adult beetles that had been exposed to marker Salmonella-inoculated feed for 72 h. In addition, chicks were gavaged with the marker Salmonella in saline solution. These chicks were then placed into pens to serve as challenged broilers. In trial 2, all pens received 2 challenged chicks that were gavaged with larvae or beetles that had been exposed to marker Salmonella-inoculated feed for 24 h and then removed from the inoculated feed for a period of 7 d. At 3 wk of age, cecal samples from the marker Salmonella-challenged broilers and from 5 pen mates in trial 1, or 10 pen mates in trial 2, were evaluated for the presence of the marker Salmonella in their ceca, and at 6 wk of age, all remaining pen mates were sampled. To monitor the presence of the marker Salmonella within pens, stepped-on drag swab litter samples were taken weekly. For the Salmonella-saline pens, 29 to 33% of the broilers that had been challenged and 10 to 55% of the pen mates were positive at 3 wk of age, and only 2 to 6% had positive ceca at 6 wk. For the pens challenged with adult beetles, 0 to 57% of the challenged broilers and 20 to 40% of the pen mates had positive ceca at 3 wk, and 4 to 7% were positive at 6 wk. The pens challenged with larvae had the greatest percentage of marker Salmonella-positive broilers; 25 to 33% of the challenged broilers and 45 to 58% of pen mates were positive at 3 wk, and 11 to 27% were positive at 6 wk. These results demonstrated that ingestion of larval or adult beetles contaminated with a marker Salmonella could be a significant vector for transmission to broilers.

Broilers entering a processing facility can be contaminated with bacteria internally, externally, or both, and additional contamination may occur during processing. Although processing generally reduces the bacterial load on a carcass, it does not eliminate all carcass bacterial contaminants. Processing plant personnel sample carcasses daily to determine overall carcass contamination using the whole carcass rinse procedure. The objective of this study was to evaluate the potential benefit of adding sand to the whole carcass rinse and extending shaking (rinsing) duration on the recovery of bacteria from broiler carcasses. Eviscerated broiler carcasses were obtained from a commercial processing plant before the prechill final wash. Carcasses were rinsed in peptone or peptone with sand for 1 and 4 min. Rinsates were analyzed for aerobic plate count, coliforms, and Escherichia coli. Bacterial levels recovered from rinsates with sand were significantly higher than levels recovered from the peptone-only rinsates, but the increase in recovery was relatively small at 0.6 log10 cfu/mL of rinsate. There was no significant improvement in bacterial recovery when shaking duration was increased from 1 to 4 min for either rinse treatment.

Experiments were conducted to determine the relationship between poultry chilling water volume and carcass microbiology. In the first study, the volume of water used during immersion chilling was found to have a significant effect on the counts of bacteria recovered from broiler carcass halves; however, these volumes (2.1 and 16.8 L/kg) were extreme and did not reflect commercial levels. A second study using commercial chilling volumes was conducted with 3.3 L/kg (low) or 6.7 L/kg (high) distilled water in the chiller. Prechill broiler carcasses were removed from a commercial processing line, cut into left and right halves, and one-half of each pair was individually chilled in a bag containing low or high volume of water. Bags containing halves were submersed in a secondary chill tank containing approximately 150 L of an ice-water mix (0.6 degrees C). After 45 min, halves were removed, allowed to drip for 5 min, and rinsed with 100 mL of sterile water for 1 min. Rinses were analyzed for total aerobic bacteria, Escherichia coli, Enterobacteriaceae, and Campylobacter. When the numbers of bacteria in the half-carcass rinses (HCR) were compared, counts recovered from halves chilled in a low volume of water were the same as those recovered from the halves chilled with a high volume of water (P > 0.05). Levels found in the HCR ranged from 4.0 to 4.2 log(10) cfu/mL for aerobic bacteria, 3.3 to 3.5 log(10) cfu/mL for E. coli, 3.6 to 3.8 log(10) cfu/mL for Enterobacteriaceae, and 2.4 to 2.6 log(10) cfu/mL for Campylobacter. Data were also analyzed using a paired comparison t-test, and this analysis showed that there was no difference (P > 0.05) in the numbers of aerobic bacteria, E. coli, Enterobacteriaceae, or Campylobacter recovered from paired-halves chilled in different volumes of water. The present study shows that under the conditions outlined in this experiment, doubling the amount of water during immersion chilling (3.3 vs. 6.7 L/kg) did not improve the removal of bacteria from the surfaces of chilled carcasses.

Breeder flocks and commercial hatcheries represent an early contamination point for Salmonella entry into commercial integrated poultry operations. Utilizing effective antimicrobial treatments for hatching eggs is a critical part of reducing the incidence of Salmonella-colonized chicks on the farm. The objective of this study was to evaluate the bactericidal effect of several chemicals on Salmonella-contaminated hatching eggs. Four replications (n = 10/treatment per replicate) were conducted to determine the efficacy of 7 commercially available compounds. The compounds tested were as follows: 1) hydrogen peroxide, 2) water-oil emulsion droplets stabilized by detergent, 3) peroxyacetic acid, 4) 4 quaternary ammonium compounds attached to a polymer, 5) 2 quaternary ammonium compounds, 1 biguanide compound and bronopol attached to a polymer, 6) N-alkyl dimethyl benzyl ammonium chloride and stabilized urea, and 7) polyhexamethylenebiguanide hydrochloride. A naladixic acid-resistant Salmonella serovar Typhimurium was inoculated (103 cfu/mL) onto fertile hatching eggs by drip-inoculation. Controls included a positive control (no spray application) and a water control (spray containing water to take into account rinsing effects). Compounds 5 and 7 had a 100% reduction, and both of these chemicals included a biguanide. Compounds 4 and 3 were also effective with a 95 and 93.5% reduction, respectively. Compounds 6 and 2 were the least effective of all chemicals, with a reduction of 47.5 and 40%, respectively. Hydrogen peroxide (compound 1), which has been used by the poultry industry, had a 70% reduction, and the water control produced a 10% reduction due to the rinsing effect. Several antimicrobials tested were more effective than hydrogen peroxide. More detailed studies will be required to adequately evaluate these antimicrobials.

SUMMARY Previous studies have demonstrated that when Campylobacter or Salmonella were either orally or intracloacally inoculated into day-old broiler chicks, within 1 h, these bacteria moved rapidly to the lymphoid organs. These bacteria were still present 1 wk after inoculation. Two different marketage (6 and 8 wk old) broilers were obtained from 2 commercial poultry operations and brought to the laboratory for analysis. Necropsy was limited to the removal of the spleen, liver and gallbladder (L-GB), and ceca using aseptic techniques. To reduce the possibility of cross-contamination between samples, the spleen and L-GB were aseptically removed before the ceca. Samples were individually bagged, and standard laboratory procedures for Campylobacter and Salmonella were carried out for all samples. Fifty-two 6-wk-old broilers were analyzed, and Campylobacter were found in 19 of 52 L-GB, 19 of 52 spleens, and 26 of 52 ceca. Salmonella were found in 5 of 52 L-GB, 8 of 52 spleen, and 4 of 52 ceca. Eighty 8-wk-old broilers were analyzed, and Campylobacter were found in 3 of 80 L-GB, 5 of 80 spleens, and 19 of 80 ceca. Salmonella were found in 41 of 80 L-GB, 38 of 80 spleens, and 52 of 80 ceca. The internal organs of the younger birds were more heavily contaminated with Campylobacter, whereas Salmonella was the predominant organism isolated in the older birds. All Campylobacter isolates were found to be Campylobacter jejuni. The predominant Salmonella serotype was Salmonella Typhimurium; however, 7 other serotypes were found. Overall, C. jejuni was found in 22 of 132 L-GB, 24 of 132 spleen, and 45 of 132 ceca, whereas Salmonella serovars were isolated from 46 of 132 L-GB, 46 of 132 spleen, and 56 of 132 ceca. There is no doubt that these bacteria are naturally present in these organs. The significance of these reservoirs in the internal organs of commercial broilers is yet to be determined but could play a role in the microbiology of the intestinal tract and hence the final food product.

Broiler chickens from the loading dock of a commercial processing plant were sampled to determine the incidence and counts of coliforms, Escherichia coli, and pathogenic bacteria. Feathers were removed by hand from ten 6-week-old chickens from each of seven different flocks and rinsed in 400 ml of 0.1% peptone water. Heads and feet were removed and rinsed, and the picked carcass was also rinsed, each in 200 ml. The ceca, colon, and crop were aseptically removed and stomached separately in 100 ml of peptone water. Campylobacter was present in six of the seven flocks. Salmonella was isolated from 50 of the 70 carcasses, with at least 2 positive carcasses in each flock, and five-tube most-probable-number (MPN) assays were performed on positive samples. Significantly (P < 0.05) more coliforms and E. coli were found in the ceca than in the feathers, which in turn carried more than the other samples, but total external and internal counts were roughly equivalent. Counts of Campylobacter were higher in the ceca and colon than in the other samples. Salmonella was isolated in external samples from 46 of the 50 positive carcasses compared with 26 positive internal samples or 17 positives in the ceca alone. The total MPN of Salmonella was approximately equivalent in all samples, indicating that contamination was distributed through all external and internal sampling locations. Salmonella-positive samples did not carry higher counts of coliforms or E. coli, and there were no significant correlations between the indicators and pathogens in any sample. Campylobacter numbers in the ceca were correlated with Campylobacter numbers in the feathers and colon, but Salmonella numbers in those samples were not correlated. The pattern of bacterial contamination before processing is complex and highly variable.

The purpose of this study was to evaluate neck skin (NS), whole carcass rinse (WCR), and whole carcass enrichment (WCE) sampling procedures for Salmonella isolation and serogroup identification from the same broiler chicken carcass treated with air or immersion chilling. Commercially processed and eviscerated broiler carcasses were collected from a commercial processing plant, individually bagged, and transported to the pilot processing plant. In experiment 1, carcasses were air chilled to 4°C. In experiment 2, carcasses were immersion chilled with or without chlorine. After air chilling, Salmonella was detected on 78% of NS and 89% of WCE samples. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive NS samples, and two serogroups were detected on 1 Salmonella-positive NS sample. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive WCE samples, and two serogroups were detected from 3 Salmonella-positive WCE samples. After immersion chilling without chlorine, Salmonella was detected on 38% of NS, 45% of WCR, and 100% of WCE samples. Without chlorine, the 15 Salmonella-positive NS samples included 14 samples with one serogroup and 1 sample with two serogroups. Only one Salmonella serogroup was detected from WCR samples after immersion chilling. Of 40 Salmonella-positive WCE samples, 23 had a one, 14 had two, and 3 had three Salmonella serogroups. After immersion chilling with chlorine, Salmonella was detected on 35% of NS, 0% of WCR, and 90% of WCE samples. With chlorine, the 14 Salmonella-positive NS samples included 11 samples with one serogroup and 3 samples with two serogroups. No Salmonella serogroups were detected from WCR samples after immersion chilling with 20 mg/liter free chlorine. The 36 Salmonella-positive WCE samples included 21 samples with one serogroup and 15 samples with two serogroups. NS and WCE sampling methodologies yielded similar prevalence and serogroup diversity after air chilling. However, after immersion chilling with or without chlorine, WCE sampling yielded significantly higher (α ≤ 0.05) prevalence and serogroup diversity than either NS or WCR sampling methodologies.

SUMMARY A study was conducted to determine the effect of water provision to chicks before placement on performance and the incidence of unabsorbed yolk sacs. To accomplish this, a device was used that was designed to deliver water to chicks in chick baskets during holding at the hatchery and transportation to the growout house. Commercial chicks were obtained from the hatchery and held for either 24 or 48 h with or without access to water before placement. Chicks were then distributed into floor pens with ad libitum access to feed and water. At 6 wk of age, broilers were processed, and intestines were evaluated for presence or absence of an unabsorbed yolk sac and intestinal breaking strength. Body weight at placement was 2 to 6 g greater for chicks given access to water; however, this difference was not observed at any other time during the growout. Water provision during holding had no affect on feed consumption, mortality, or the birds’ ability to completely absorb the yolk sac during the 6 wk growout. Incidence of unabsorbed yolk sacs in 6 wk old birds ranged from 15 to 28%. Moreover, presence or absence of an unabsorbed yolk sac had no effect on intestinal breaking strength. Data from the present study demonstrates that providing chicks with water before placement does not influence performance, intestinal breaking strength, or the incidence of unabsorbed yolk sacs.

SUMMARY In the developing avian embryo, the main energy source is the yolk. Toward the end of the incubation period, the remaining yolk sac is internalized into the abdominal cavity. At hatch, the remaining yolk comprises 20% of the chick’s BW and provides the nutrients needed for maintenance. Posthatch, chicks rapidly initiate the transition from yolk dependence to the utilization of exogenous feed. However, at present, it is not known what types of bacteria are found to be associated with unabsorbed yolk sacs from market-age broilers. For Experiment 1, one hundred 6-wk-old defeathered broiler carcasses were obtained from a commercial processing facility during each of 3 visits. In the second experiment, one hundred 8-wk-old defeathered broiler carcasses were obtained from a different commercial processing plant on 4 separate occasions. For both experiments, each carcass was aseptically opened and inspected for the presence of an unabsorbed yolk sac. Three to 5 carcasses containing a free-floating yolk sac (within the abdominal cavity) and the yolk stalk (without a yolk sac) and 3 to 5 carcasses containing an attached yolk and yolk stalk from each repetition were randomly selected and analyzed for levels and types of total aerobic bacteria (APC), Enterobacteriaceae (ENT), and for the presence of Campylobacter spp. and Salmonella serovars. The APC ranged from log 3.3 to >log 6.0, and the ENT ranged from log 2.8 to >log 6.0. Staphylococcus spp. and Streptococcus spp. were the predominant organisms in APC, whereas Escherichia coli and Hafnia alvei were found to comprise the ENT. Campylobacter spp. was found in 29% of the yolk stalks, 32% of the attached yolk sacs, and 13% of the free-floating yolk sacs. All Campylobacter isolates were determined to be Campylobacter jejuni, except for 1 attached yolk and yolk stalk, which was Campylobacter coli. Salmonella serovars were found in 26% of the yolk stalks, 48% of the attached yolk sacs, and 23% of the free-floating yolk sacs, and the majority of Salmonella isolates were Salmonella Typhimurium. The significance of these bacterial reservoirs and carcass contamination during processing is yet to be determined.

Release of bacteria from individual broiler carcasses in warm water was measured as a model of bacterial contamination of scald water. Immediately after shackling and electrocution, feathered and genetically featherless broiler carcasses (n = 24 of each) were immersed individually in 42°C, air-agitated tap water for 150 s. Although any visible fecal material expelled as a result of electrocution was removed before sampling, carcass condition was typical for market-age broilers subjected to 12 h of feed withdrawal. Duplicate water samples were taken at 10, 30, 70, 110, and 150 s, and Escherichia coli counts were determined. Samples of initial tap water and contaminated water approximately 2 min after removal of carcasses indicated that E. coli could not be detected in the original water source and that mortality of E. coli in the warm water was negligible. Mean numbers of E. coli released were 6.2 and 5.5 log10 (cfu/carcass) at 150 s for feathered and featherless carcasses, respectively. For both feathered and featherless carcasses, the rate of release of E. coli was highest in the first 10 s, and the rate declined steadily during the remaining sampling period. This result is compatible with published reports of sampling of operating multiple-tank scalders, indicating that a high proportion of total bacteria in a multiple-tank scalder are in the first scald tank that carcasses enter. Higher numbers of E. coli released from feathered carcasses are probably due to the much greater surface area of contaminated feathers compared with the skin of featherless carcasses.

Two studies were conducted to determine whether Campylobacter jejuni could rapidly spread and reside in the internal organs of adult broiler breeder hens. In Study 1, university-housed broiler breeders at 22 wk of age were obtained and placed in individual cages. Each hen was intravaginally inoculated weekly from 23 to 32 wk of age with a characterized strain of C. jejuni. At wk 23, 27, and 32, 4 d postinoculation, the hens were euthanized, defeathered, and aseptically opened. In Study 2, university-housed broiler breeder hens were obtained at 42, 53, and 56 wk of age, placed in individual cages, and inoculated either orally or intravaginally with a characterized strain of C. jejuni. To reduce the possibility of cross-contamination among samples, the thymus, spleen, liver, and gallbladder were aseptically removed, prior to the ceca. In both studies, all samples were individually analyzed. In Study 1, at 23 wk of age, C. jejuni was recovered from 4/7 thymii, 2/7 spleens, 5/7 livers and gallbladders, and 6/7 ceca. At 27 wk of age, C. jejuni was recovered from 1/7 thymii and 1/7 ceca. At 32 wk of age, C. jejuni was recovered from 4/11 thymii, 1/11 livers and gallbladders, and 2/11 ceca. In Study 2, C. jejuni was recovered from 2/6 thymii and 5/6 ceca after oral inoculation and 1/6 spleens, 1/6 livers and gallbladders, and 4/6 ceca after vaginal inoculation of 43-wk-old hens. Campylobacter jejuni was recovered from 2/5 thymii, 3/5 spleens, 3/5 livers and gallbladders, and 2/5 ceca after oral inoculation of 53-wk-old hens and 1/5 thymii and 1/5 livers and gallbladders after vaginal inoculation. Campylobacter jejuni was recovered from 1/4 thymii, 2/4 livers and gallbladders, and 1/4 ceca and was not detected in any vaginally inoculated birds of 57-wk-old hens. This study provides evidence that C. jejuni can reside in the internal organs of broiler breeder hens following oral or intravaginal inoculation.

Unabsorbed yolk sacs are being investigated as a possible reservoir for internal Campylobacter and salmonellae contamination of processed poultry carcasses. However, it is unknown at what frequency that unabsorbed yolk sacs persist at the time of processing of broilers and spent breeders. Seven sets of 100 broiler carcasses (at 6 or 8 wk of age) were obtained from commercial processing plants. In addition, 100 52-wk-old broiler breeder males, 100 102-wk-old Leghorn hens, and 300 8-wk-old Athens-Canadian randombred control (ACRBC) broilers were euthanized, and their abdominal cavities were opened for determination of the presence of unabsorbed yolk sacs. Carcasses with obliterated yolk stalks or stalks with no detectable yolk material were categorized as normal. Those with unabsorbed yolk sacs were further separated into 2 groups: 1) attached by the yolk stalk to the small intestine or 2) unattached within the abdominal cavity. Yolk sacs were further classified by size: 1) small was2 mm in diameter, 2) medium was 2 to 10 mm, and 3) large was10 mm. From the 300 commercial broiler carcasses that were 6 wk old, 54% were categorized as normal with no detectable yolk sac, 35% had an unabsorbed yolk sac attached to the yolk stalk, and 12% had unattached yolk sacs. From the 400 commercial broiler carcasses that were 8 wk old, 49% of the carcasses were normal, 31% had attached unabsorbed yolk sacs, and 20% had unattached yolk sacs. From the 100 rooster carcasses sampled, 73% were normal, 8% had attached unabsorbed yolk sacs, and 19% had unattached yolk sacs. From the 100 White Leghorn hen carcasses sampled, 88% were normal, 8% had attached unabsorbed yolk sacs, and 4% were unattached yolk sacs. From the 300 ACRBC carcasses sampled, 76% were normal, 4% had attached unabsorbed yolk sacs, and 20% were unattached yolk sacs. The incidence of unabsorbed yolk sacs in present day commercial broilers appears twice as high as for mature roosters, hens, or ACRBC broilers.

We previously reported the recovery of Campylobacter (naturally colonized) from the ductus deferens of 5 of 101 broiler breeder roosters, and four of those five positive roosters had previously produced Campylobacter-positive semen samples. Those results prompted further evaluation to determine if inoculation route influenced the prevalence or level of Campylobacter contamination of semen, the digestive tract, or reproductive organs. Individually caged roosters, confirmed to be feces and semen negative for Campylobacter, were challenged with a marker strain of Campylobacter jejuni either orally using 1.0 ml of a diluted cell suspension (log(10)4.3 to 6.0 cells), by dropping 0.1 ml of suspension (log(10)5.3 to 7.0 cells) on the everted phallus immediately after semen collection or by dip coating an ultrasound probe in the diluted cell suspension (log(10)4.3 to 6.0 cells) and then inserting the probe through the vent into the colon. Six days postinoculation, individual feces and semen samples were again collected and cultured for Campylobacter. Seven days postinoculation, roosters were killed, the abdomen aseptically opened to expose the viscera, and one cecum, one testis, and both ductus deferens were collected. The samples were then suspended 1:3 (weight/volume) in Bolton enrichment broth for the culture of Campylobacter. Samples were also directly plated onto Cefex agar to enumerate Campylobacter. Campylobacter was recovered 6 days after challenge from feces in 82% of samples (log(10)4.1 colony-forming units [CFU]/g sample), 85% of semen samples (log(10)2.9 CFU/ml), and on the seventh day postchallenge from 88% of cecal samples (log(10)5.8 CFU/g sample). Campylobacter was not directly isolated from any testis sample but was detected following enrichment from 9% (3/33) of ductus deferens samples. Roosters challenged with Campylobacter orally, on the phallus, or by insertion of a Campylobacter dip-coated ultrasound probe were all readily colonized in the ceca and produced Campylobacter-positive semen and feces on day 6 after challenge. The low prevalence of recovery of Campylobacter from the ductus deferens samples and failure to recover from any testis sample suggests that semen may become Campylobacter positive while traversing the cloaca upon the everted phallus. The production of Campylobacter-positive semen could provide a route in addition to fecal-oral for the horizontal transmission of Campylobacter from the rooster to the reproductive tract of the hen.

Feathered and featherless (scaleless) sibling broilers were reared and processed together to evaluate the influence of feathers and feather follicles on carcass bacteria recovery after chilling. In each experiment, broilers were inoculated 1 wk prior to processing by oral gavage with a suspension of salmonellae or Campylobacter at 106 cells/mL. Broilers were stunned and bled, and carcasses were single-tank or triple-tank scalded, defeathered, eviscerated, and washed. Carcasses were chilled for 45 min in ice and water immersion chillers with or without 20 mg of chlorine/L added. Postchill carcass rinsates were evaluated for Escherichia coli, coliforms, total aerobes, and salmonellae or Campylobacter. Following processing and immersion chilling, genetically featherless carcasses had slightly higher counts (by log10 0.35 cfu/100 mL of carcass rinsate) for E. coli, coliforms, and total aerobes than feathered carcasses. However, there were no significant differences in the prevalence of salmonellae (25%) or Campylobacter (93%) between feathered and featherless carcasses. Recovery of E. coli, coliforms, and total aerobic bacteria were lower for carcasses that were single-tank scalded, and following enrichment, salmonellae were recovered from fewer carcasses subjected to the single-tank (71%) than triple-tank (86%) scalding. Addition of chlorine to chiller water significantly decreased carcass bacteria recovery (by log10 0.43 cfu/100 mL of carcass rinsate) for E. coli, coliforms, total aerobes, and Campylobacter but did not affect salmonellae recovery. The presence of feathers and feather follicles during processing and immersion chilling appears to have minimal influence on the recovery of salmonellae or Campylobacter from carcasses sampled after immersion chilling.

SUMMARY By using a technique that previously demonstrated improved efficiency of intact crop removal for broilers, experiments were conducted to determine the effectiveness of the technique in 40and 41-wk-old broiler breeder roosters and hens. The technique involved (after scalding, defeathering, and head removal) separating (breaking) the neck from the carcass parallel with the shoulders and leaving the ventral neck skin, trachea, and esophagus intact. With an individual carcass suspended by its wings from a shackle, the esophagus was grasped above the proventriculus within the thoracic cavity, and the crop was pulled through the thoracic inlet. The maximum load required to remove the crop from the carcass was recorded, and it was determined if the crops removed were intact or ruptured. Carcasses that had the neck broken prior to crop removal had significantlymorecropsremovedintact(85%,35of40)forbothroosterandhencarcassescompared with only 20% removed intact (8 of 40 carcasses) for rooster and hen carcasses in which the neck remained unbroken. The load required to remove the crop was influenced by gender and treatment. Rooster carcasses required a higher load (5.7 kg) than hen carcasses (4.9 kg), and for rooster carcasses, breaking the neck prior to evisceration resulted in a lower load (5.2 kg) to remove the crop than that of carcasses in which the neck remained unbroken (6.2 kg). The difference (0.2 kg) in the load recorded for crops removed intact and those that ruptured was not significant and suggeststhatcropsrupturedduringremovalresultedfromexternalattachmentsandnottoinherent weakness. Breaking the neck of broiler breeder carcasses prior to evisceration improved the efficiency of intact crop removal (85% removed intact) and would thereby minimize the incidence of crop contents contaminating the carcass during evisceration.

Trisodium phosphate (TSP) has been reported to decrease the recovery of salmonellae from processed poultry carcasses. It has been suggested that the high pH and detergent-like properties of TSP solutions are responsible for the reduction in salmonellae recovery. This project was conducted to determine if controlling pH during salmonellae pre-enrichment alters the effect of TSP on salmonellae recovery. Carcasses were obtained from a commercial processing plant immediately after the final inside-outside carcass washer, prior to any other antimicrobial treatments, and before chilling. Carcasses were assigned to 1 of 4 treatment groups: (1) TSP and alkaline pre-enrichment, (2) TSP and neutral pre-enrichment, (3) non-TSP and alkaline pre-enrichment, 4) non-TSP and neutral pre-enrichment. Carcasses were placed into plastic bags with 500 mL of buffered peptone water (with or without pH adjustment) and shaken for 1 min. Preincubation pH of the rinsate was measured. Carcasses were incubated in the rinse at 37 degrees C for 24 h, and incidence of salmonellae was determined. The pH of the preincubation rinsate was 8.4 for the TSP alkaline pre-enrichment, 7.2 for the TSP neutral pre-enrichment, 8.6 for the non-TSP alkaline pre-enrichment, and 7.1 for the non-TSP neutral pre-enrichment. Salmonellae were detected from 40% of the TSP alkaline pre-enrichment carcasses, 44% of the TSP neutral pre-enrichment carcasses, 54% of the non-TSP alkaline pre-enrichment carcasses, and 38% of the non-TSP neutral pre-enrichment carcasses. Neither TSP treatment nor pre-enrichment pH adjustment significantly influenced carcass salmonellae detection.

Recent studies have shown a significant level of Campylobacter in the semen of midlife and late-life broiler breeder roosters. The present study was conducted to determine if several foodborne pathogens (Campylobacter, Salmonella, and Clostridium perfringens) could be isolated from the ductus deferens, testes, and ceca of 45- to 65-wk-old commercial broiler breeder roosters. Five roosters from each of 3 separate commercial housed breeder farms were transported to the laboratory. An aseptic necropsy was performed to remove the ductus deferens, testes, and ceca without surface contamination from blood and other tissues. All samples were analyzed for each of the 3 previously mentioned bacteria, total aerobic bacteria, and Enterobacteriaceae. None of the 3 foodborne pathogens were isolated from the testes of the 15 commercial roosters. Clostridium perfringens was isolated from 1 of the 15 ductus deferens, whereas no Campylobacter or Salmonella were isolated from this tissue. Campylobacter was cultured from the ceca of all 15 roosters, Clostridium perfringens from 14/15, and Salmonella from 2/15. One-quarter of all commercial broiler breeder's semen samples were found to be contaminated with Campylobacter in a previous study; however, this organism as well as Salmonella and Clostridium perfringens were not found in the reproductive tissues located in the abdominal region. Escherichia coli and Enterococcus faecium were occasionally cultured from the ductus deferens. These data suggest that the contamination of semen by these foodborne pathogens is via fecal or cecal contamination as the semen passes through the cloaca and not from bacterial colonization of the testes and ductus deferens.

Genetically featherless and feathered broiler siblings were used to test the contribution of feathers and feather follicles to the numbers of aerobic bacteria, Escherichia coli, and Campylobacter in whole-carcass rinse samples taken immediately after carcasses were defeathered for 30 or 60 s. Numbers of spoilage bacteria were counted after the same fully processed carcasses were stored for 1 wk at 2 degrees C. In each of 3 replications, twenty-eight 11-wk-old, mixed-sex, genetically featherless or feathered broilers were processed in a laboratory processing facility. Immediately after individual defeathering in a mechanical picker, carcasses were sampled using a carcass rinse technique. Carcasses were eviscerated, immersion chilled at 2 degrees C for 30 min, individually bagged, and stored for 1 wk at 2 degrees C, after which all carcasses were rinsed again, and spoilage bacteria in the rinsate were enumerated. There were no significant differences (P < or = 0.05) between the featherless and feathered broilers in numbers of aerobic bacteria, E. coli, and Campylobacter in rinse samples taken immediately after defeathering and no differences between carcasses picked for 30 or 60 s. There were no differences in numbers of spoilage bacteria after 1 wk of refrigeration for any of the feather presence-picking length combinations. Although the defeathering step in poultry processing has been identified as an opportunity for bacterial contamination from the intestinal tract and cross-contamination between carcasses, the presence of feathers and feather follicles does not make a significant difference in carcass bacterial contamination immediately after defeathering or in spoilage bacteria after 1 wk of refrigeration.