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Aims: While considerable foodborne pathogen research has been conducted on conventionally produced broilers and turkeys, few studies have focused on free-range (organic) or pastured poultry. The current surveillance study was designed to isolate, identify and genetically characterize Salmonella from pastured poultry farm environment and from retail samples. Methods and Results: In this study, 59 isolates were collected from two pastured poultry farms (n = 164; pens, feed, water and insect traps) and retail carcasses (n = 36) from a local natural foods store and a local processing plant. All isolates were serotyped and analysed phenotypically (antimicrobial resistance profiles) and genotypically (DNA fingerprints, plasmid profiles and integron analysis). Salmonella enterica was detected using standard microbiological methods. Salmonella Kentucky was the most prevalent serotype detected from the sampled sources (53%), followed by Salmonella Enteritidis (24%), Bareilly (10%), Mbandaka (7%), Montevideo (5%) or Newport (2%). All isolates were resistant to sulfisoxazole and novobiocin, and the majority (40/59) possessed class I integrons shown by PCR detection. Each Salmonella serotype elicited a distinct pulsed-field gel electrophoresis fingerprint profile, and unique differences were observed among the serotypes. Conclusions: The findings of this study show that Salmonella serotypes isolated from pasture-raised poultry exhibit antimicrobial resistance and class I integrons. Significance and Impact of the Study: This study demonstrates that despite the cessation of antibiotic usage in poultry production, antibiotic resistant Salmonella may still be recovered from the environment and poultry products.

In the mind of the general public, the words "arsenic" and "poison" have become almost synonymous. Yet, As is a natural metallic element found in low concentrations in virtually every part of the environment, including foods. Mining and smelting activities are closely associated with As, and the largest occurrence of As contamination in the United States is near the gold mines of northern Nevada. Inhabitants of Bangladesh and surrounding areas have been exposed to water that is naturally and heavily contaminated with As, causing what the World Health Organization has described as the worst mass poisoning in history. Although readily absorbed by humans, most inorganic As (>90%) is rapidly cleared from the blood with a half-life of 1 to 2 h, and 40 to 70% of the As intake is absorbed, metabolized, and excreted within 48 h. Arsenic does not appreciably bioaccumulate, nor does it biomagnify in the food chain. The United States has for some time purchased more As than any other country in the world, but As usage is waning, and further reductions appear likely. Arsenic is used in a wide variety of industrial applications, from computers to fireworks. All feed additives used in US poultry feeds must meet the strict requirements of the US Food and Drug Administration Center for Veterinary Medicine (Rockville, MD) before use. Although some public health investigators have identified poultry products as a potentially significant source of total As exposure for Americans, studies consistently demonstrate that

Food-borne salmonellosis continues to be a major public health concern, and contamination with Salmonella spp. in pre-harvest animal production is considered a primary contributor to this problem. Animal feeds can easily become contaminated during primary production, feed mixing and processing as well as during feeding. Consequently, monitoring and surveillance of feeds and feed ingredients for Salmonella spp. contamination may be useful or necessary in the prevention and control of this organism. Cultural and immunological detection methods for salmonellae have been used or suggested as possible approaches for use in animal feeds. Cultural methods remain advantageous owing to their ability to detect viable bacterial cells, while immunological methods have the capability of detecting nonculturable bacterial cells. Advancements and improvements in both methodologies offer opportunities for eventual routine use of these detection technologies in animal feed assays.

Foodborne salmonellosis continues to be a public health issue of considerable concern. Animal feed has been a major link in pre-harvest food animal production. Although monitoring systems and control measures are available to limit Salmonella spp. contamination on animal feeds detection methodology is relatively time consuming in the context of time inputs for feed processing and mixing. Current cultural methods of Salmonella spp. detection in feeds require several days for confirmation. This amount of time represents significant problems if control measures are to be effectively implemented in a fashion that keeps feed processing costs low. Molecular methods offer improved sensitivity and potential reduction in assay time. In particular, several commercial polymerase chain reaction (PCR) assays, and combined PCR-hybridization assays have been suggested as possible means to implement more rapid detection of Salmonella spp. extracted from animal feeds. It has now become possible to rapidly detect and confirm the presence of foodborne Salmonella spp. in feed matrices by commercial amplification detection systems. The primary challenges remaining are to develop more reliable recovery and extraction procedures for routine processing of samples from a wide variety of feed matrices and apply molecular techniques for assessing physiological status of Salmonella spp. contaminants in animal feeds.

We collected 886 samples (68 feed ingredient samples, 189 dust samples, and 629 feed samples) from 3 feed mills each of which produced between 100,000 and 400,000 tons of feed a year. Samples were collected on 3 d (Monday, Wednesday, and Friday), during 2 seasons (early spring and summer), and between 0700 and 1700 h approximately once per hour. Samples were collected from 5 locations within each mill: ingredient receiving, at the mixer, at the pellet mill, from pellet coolers, and at load-out. Temperatures were taken of the samples obtained at the pellet mill immediately following collection. All samples were analyzed for Enterobacteriaceae counts (EC) and Salmonella. The data confirm that feed ingredients and dust can be a major source of Salmonella contamination in feed mills. There were no differences (P < 0.05) in the Salmonella contamination rates of samples collected in spring as compared with samples collected in summer. Salmonella contamination rates were observed to be higher in samples collected on Friday compared with samples collected on Monday or Wednesday, an effect that may be management related. Data collected at the pellet mill clearly illustrate the uneven distribution of Salmonella contamination in feed as well as the need for control of dust around the pellet mill. Feed samples (both mash and pellets) contaminated with Salmonella contained significantly higher EC than samples not contaminated with Salmonella. Thus, EC may provide some indication of the likelihood of Salmonella contamination in feed samples.

Two trials were conducted to determine whether deep stacking of contaminated corn with poultry litter destroys aflatoxin. Contaminated corn was ground and mixed with litter to carbon:nitrogen ratios of 30:1. Moistures were adjusted by adding tap water just prior to incubation or stacking. The initial laboratory trial included only broiler litter at 40% moisture, whereas the subsequent field trial involved a 2 x 2 factorial design with litter type (turkey or broiler) and moisture (20 or 40%) as main effects. Aflatoxin assays were reduced in the laboratory trial from 433 and 402 to 54 and 8 ppb in Containers 1 and 2, respectively, after 35 d of incubation at 28 C. In the field trial, aflatoxin disappeared from broiler and turkey litter mixtures with projected moistures of 20% after 10 and 6 wk of storage, respectively, whereas disappearance in mixtures containing projected moistures of 40% required 5 and 3 wk, respectively. Differences in moisture appear to account for differences in the ability of turkey and broiler litter to detoxify aflatoxin. Hence, turkey and broiler litter would appear equal with respect to the ability to detoxify aflatoxin-contaminated corn. Disappearance of aflatoxin during storage with litter could have occurred as a result of ammonia release during storage or microbial detoxification mechanisms. However, nitrogen values suggest that microbial action was responsible for much of the detoxification, as aflatoxin disappeared from mixtures with little apparent ammonia release.

Corn purchased from commercial sources was split at delivery and was left untreated or treated with a commercial mold inhibitor. Feed was prepared from these two lots of corn from within 1 wk to as much as 20 wk after delivery over the course of two experiments. There was evidence of reduced mold growth due to the mold inhibitor, particularly in the second experiment where initial mold populations were higher. Mycotoxins were evident in feed samples, regardless of the corn treatment. There was no significant effect from the treatment of corn on growth, livability, egg production, feed conversion, egg weight, or the eggshell quality of broiler breeders. Treatment of corn with a mold inhibitor significantly increased hatchability of fertile eggs in both experiments. Fertility was also significantly improved in the second experiment. These data suggest that using corn treated with a mold inhibitor results in significantly better hatchability in broiler breeders than untreated corn, although there were no observed differences in the incidence of mycotoxins in the samples taken.

Antimicrobials are powerful tools, but controversy and conflict often follow power. The development of antimicrobials was marked by personal attacks, political intrigue, internal conflicts, and lawsuits. Such controversy and conflict has continued. The early history of supplementing animal feeds with antimicrobials parallels the isolation and identification of vitamin B12. Vitamin B12 was isolated and characterized in 1948, but further research showed that several feed ingredients, including dried mycelia of certain fungi, were more potent as growth promoters in the diet of chicks than was vitamin B12 alone. The growth-promoting component in fungal mycelia was shown to have antimicrobial activity. A total of 32 antimicrobial compounds are approved for use in broiler feeds in the U.S. without a veterinary prescription. Fifteen compounds are listed for treatment of coccidiosis, 11 are listed as growth promotants, and six are listed for other purposes. Seven compounds are also used in human medicine. These compounds include bacitracin, chlotetracycline, erythromycin, lincomycin, novobiocin, oxytetracycline, and penicillin. No published estimates of antimicrobial use in animals exist at present, and estimates of that use differ markedly. The Union of Concerned Scientists (UCS) estimates usage at 30.6 million pounds, nearly 50% (49.85%) higher than the Animal Health Institute (AHI) estimate of 20.42 million pounds. AHI surveyed their members (the manufacturers of antimicrobials) to obtain their estimates, whereas USC calculated their estimates using published data and the following general formula: antimicrobial use = number of animals treated x average days treated x average dose.

This study was conducted to investigate the effects of cryogenic cooling on shell egg quality. Gaseous nitrogen (GN), liquid nitrogen (LN), and gaseous carbon dioxide (GC) were utilized to rapidly cool eggs in a commercial egg processing facility and were compared to traditional cooling (TC). A modified food freezer was attached to existing egg processing equipment in order to expose eggs to the selected cryogen. In Experiment 1, eggs were treated with GN, LN, and TC then stored and tested over 10 wk. Experiment 2 eggs were treated (GC and TC) and evaluated for 12 wk. Quality factors that were measured included Haugh units, vitelline membrane strength and deformation at rupture, and USDA shell egg grades for quality defects. Haugh unit values were greater for cryogenically treated eggs as compared to traditionally cooled eggs (Experiment 1: 73.27, GN; 72.03, LN; and 71.4, TC and Experiment 2: 74.42, GC and 70.18, TC). The percentage of loss eggs in the GN treatment was significantly (P < 0.01) greater than those of the LN and TC treatments. Vitelline membrane strength was greater for the cryogenically cooled eggs versus traditional processing. Vitelline membrane breaking strength decreased over storage time. Vitelline membrane deformation at rupture was significantly (P < 0.05) greater for the cryogenically cooled eggs compared to the traditional eggs in each experiment. Use of the technology could allow for egg quality to be maintained for a longer time, which could increase international markets and potentially lead to extended shelf lives.

Three Ottawa control strains and a current commercial laying stock were reared and housed under identical environmental and management conditions. Eggs were collected from each strain when hens were 32, 45, 58, 71, and 84 wk of age. The eggs were inoculated with Salmonella enteritidis (SE), Pseudomonasfluorescens (PF), or a combination of the two. After storage at 26 C, bacterial counts were obtained from the exterior shell surfaces (rinse), air cell, egg contents, and shell structure. SE and PF survived at different rates on the shell surface with as much as a 1 log difference during a given collection period. Egg content counts tended to be higher than eggshell counts in PF, whereas the opposite was true for SE. These data suggest that PF is a primary invader of eggs that is more capable of contaminating egg contents through the shell membranes than SE. The PF and SE data suggest that bacterial contamination of air cells, shells, and egg contents is more easily achieved in eggs from older hens than from younger hens. There were also differences between the strains. Control Strain 10 consistently maintained a lower level of contamination for both organisms in each sampling location. The overall results of this study suggest that genetic selection has altered the ability of eggs to resist microbial contamination and that screening for microbial integrity should be considered in the selection process among the laying egg breeders.

The effects of hen age, Escherichia coli, and dietary Bio-Mos and Flavomycin on poult performance from 1 to 21 d were studied. Day-of-hatch BUTA (BIG-6) male poults were gavaged orally (1 mL) with approximately 10(8) cfu/mL E. coli composed of four serotypes or sterile carrier broth. A mixture of the same E. coli cultures was added to the poults' water troughs to attain a concentration of approximately 10(6) cfu/mL on a weekly basis to ensure a continuous bacterial challenge. Within each E. coli split plot treatment group, poults from hens of different ages (33 and 58 wk of age) were fed diets containing Bio-Mos (1 g/kg feed), Flavomycin (2.2 mg active ingredient/kg feed), Bio-Mos plus Flavomycin, or a control diet, in a randomized complete block design. This experiment yielded eight treatments per challenge group. At Weeks 1 and 3, eight birds from each treatment from the E. coli challenged and unchallenged groups were randomly chosen for bacterial sampling of liver and intestinal tissue for coliforms, aerobic bacteria, and Lactobacillus spp. E. coli isolates from tissue samples were O serotyped. During E. coli challenge, dietary Bio-Mos and Flavomycin improved poult BW and BW gains (P < or = 0.05). When poults were not challenged with E. coli, poults from old hens had improved BW and cumulative BW gains over poults from young hens (P < or = 0.05). Cumulative 3-wk BW gains for unchallenged poults from young hens were improved by Bio-Mos and Flavomycin (P < or = 0.05) alone and in combination when compared to the control diet. Two of the four E. coli serotypes administered were recovered. Several serotypes were recovered that were not administered. It may be concluded that dietary Bio-Mos and Flavomycin can improve the overall performance of poults, especially when they are faced with an E. coli challenge.

The effect of long-term genetic selection on physical quality and composition of eggs was determined by analyzing eggs acquired from Agriculture Canada: Ottawa Control Strain 5 (CS5) from a 1950 base population, 7 (CS7) from a 1958 population and 10 (CS10) from a 1972 population. Eggs from the HN "Nick Chick" current commercial strain (CCS) were also included. Eggs were collected monthly over a 62-wk laying period and analyzed for egg, albumen, shell and yolk weight; albumen protein, solids and pH; percentage yolk solids and fat; Haugh units; and specific gravity. Significant (P0.05) differences found between strains included a progressive increase in weight of eggs from the CS5 to CCS. Although the eggs increased in size, no significant differences were found between strains for specific gravity or percentage shell weight. Yolk weights of eggs from the strains examined did not differ. However, the percentage of yolk found in current strain eggs was significantly lower (P0.05), with a subsequent higher percentage albumen due to the increase in egg size of the CCS. Haugh units were significantly higher in the CS10 and CCS strains than in the other strains. No significant differences between strains were seen in albumen protein, solids, pH, or yolk solids. Mean percentage yolk fat assay values for eggs from the CS5, CS7, CS10, and CCS strains were 33.08, 32.68, 32.84, and 32.40, respectively. Percentage yolk fat values obtained from CCS were significantly lower (P0.05) than those obtained from the other strains. The results from this study indicate that genetic selection has produced larger eggs containing a lower percentage of yolk while overall egg quality has been maintained or improved.

Egg samples were collected from various stages of an egg processing operation and from the attached production facility. Salmonella was isolated from 72.0% of all samples collected from the laying house environment. Recovery of Salmonella from flush water, ventilation fan, egg belt, and egg collector samples were (positive samples/total samples collected): 2/2, 4/4, 16/22, and 14/22, respectively. Salmonella was found on 7 of the 90 eggshells sampled before processing and 1 of 90 eggshells sampled after processing, but Salmonella was not found in the 180 eggs analyzed for internal contamination following processing. The one eggshell found positive for Salmonella following processing was detected when the pH of wash water samples was lowest (10.19). The 60 isolates from production facilities included the following Salmonella serotypes: S. agona, S. typhimurium, S. infantis, S. derby, S. heidelberg, S. california, S. montevideo, S. mbandaka, and untypable. The 22 isolates obtained from eggshells prior to processing were serotyped as S. heidelberg and S. montevideo. All five isolates obtained from eggshells after processing were serotyped as S. heidelberg. These data suggest that although the shells of about 1% of commercial eggs are contaminated with Salmonella, contamination of the internal contents of eggs with Salmonella is a rare event.

The potential of a novel oxy-halogen compound (OHC) to alter early growth and nitrogen retention of broiler chickens challenged with Salmonella was evaluated. Three hundred and twenty female broiler chicks (Arbor Acres × Arbor Acres) were weighed and distributed randomly within a 2 × 4 factorial arrangement of treatments. Main effects examined were the presence or absence of Salmonella typhimurium (ST) inoculation and OHC treatment. At hatching, 80 chicks were placed in electrically heated brooder batteries in each of four identical isolation rooms. Chicks designated to receive 100 μL of an oral inoculum containing 105 ST cfu at 3 days of age were in two of the rooms, and uninoculated chicks were raised in the other two rooms. Four replicates of 10 chicks each received drinking water containing either 0, .05, .1, or .5% OHC for each level of ST. Chicks administered .05% OHC exhibited enhanced (P ≤ .01) growth at 7 and 14 days of age when compared with control values. A significant OHC by ST interaction was observed at 7 (P ≤ .0001) and 14 (P ≤ .03) days of age. Feed utilization was improved (P ≤ .01) by OHC administration (.05 and .1%) from hatching to 7 days of age. The administration of OHC reduced (P ≤ .01) nitrogen excretion and enhanced (P ≤ .01) nitrogen retention by chicks at Day 7. Cecal ST log10 counts at 7 days of age for chicks given water containing 0, .05, or .1% OHC were 4.72, 3.93, and 3.74, respectively. Oral administration of .05 and .1% OHC enhanced the performance of neonatal chickens.

Antibiotic resistance in microorganisms has become a significant problem worldwide. Although use of antimicrobial growth promoters (AGP) remains controversial, the data for implicating a direct link to human health hazards from feeding AGP remain uncertain. Nonetheless, the public sector is building pressure to outlaw the practice. Thus, it seems inevitable that the use of AGP will decline in the future. In view of this situation, this symposium was organized to briefly review the history of the issue, assess the current status, and examine possible AGP alternatives. Dibner and Richards provide readers with a review of AGP use in the commercial animal industry over the years as an overview of the history of legislation in the United States and Europe. In addition, they examine the biological basis for antibiotic effects on animal growth efficiency. Finally, they discuss possible replacement compounds for AGP and conclude that it is “… unlikely that a single replacement will be found that will prove to be economically viable.” By water reviews evidence that antimicrobial use in animal production has resulted in harm to human health and concludes that such evidence remains elusive. The author suggests that well-designed surveillance programs are essential in assessing the qualitative and quantitative risks associated with individual AGP agents. Anderson et al. consider the use of experimental chlorate preparations as a preharvest intervention technology to prevent the colonization of food producing animals with pathogens. Huff and co-authors examine the bacteriophage administration for controlling foodborne pathogens and Escherichia coli infections. Berghman et al. discuss...

Feed samples were collected from the feed mill and four growers from each of two commercial broiler companies. Two sets of samples were collected from the first, middle, and last feeders in each poultry house. Feed samples were analyzed for mean particle size, respiratory CO2, moisture, percent fines, and zinc concentration. A significant (P

Samples of apparently normal feed and feed ingredients were collected from turkey, broiler chicken, and laying hen operations, and their moisture content, mold count, coliform count, and pH were determined. The moisture contents ranged from 10.59 to 17.40%, the mold counts ranged from 5 to 1,200,000/g, and the coliform counts ranged from 5 to 910,000/g with corn meal being the major source for each. The pH values of feed ranged from 5.42 to 7.30 with the ingredients ranging from 5.21 to 11.51. Feed that had been pelleted generally had a lower mold and coliform count and a higher moisture content while the pH was affected (.1 unit higher) only in turkey feed. Feed samples of suspect microbiological quality were surveyed and their median moisture content, mold count, and coliform count were higher and their pH lower than the corresponding median values for apparently normal feed. These data indicate there is a need for improved quality control in feed manufacture and storage.

Paired samples of mash and pellets made from the mash were taken at feed mills and compared for their mold count and fungal activity as measured by metabolic CO2 production. Four paired samples contained Mold-X, a commercial mold inhibitor, of which the major active ingredient is propionic acid, and four paired samples did not contain a mold inhibitor. Pelleting reduced the mold counts by a factor of about 100 to 10,000, depending upon the sample. Incubation of the samples at 29 C after adjusting the water content to 20, 25, or 30% caused an approximate doubling of the time required for onset of metabolic CO2 production by the pelleted feed as compared to the mash. Incorporation of the mold inhibitor into mash appeared to give a similar lag in onset of CO2 production. Pellets made from mash containing the mold inhibitor had an additional doubling in the delay of onset of CO2 production. In a model system composed of corn meal to which graded doses of propionic acid were added, the concentration of inhibitor that provided 50% inhibition was found to increase with time of incubation. The lag in onset of CO2 production in this system was found to be 1 or 2 days depending on whether the corn meal was heated for 5 min at 60 or 70 to 85 C, respectively. Heat and propionic acid also interacted to reduce the mold count of corn meal in the model system. It would appear that the effectiveness of propionic acid as a mold inhibitor can -be greatly increased by the pelleting process and that a decrease in the fungal burden of feed is an attribute of pelleting.

Three of five houses on a commercial broiler farm were cleaned, and hardwood sawdust was spread to a depth of about 3 cm prior to the arrival of chicks. Hard or caked litter was removed from the remaining two houses, and litter was top dressed with about .25 cm of hardwood sawdust. Litter samples were collected weekly from each house. Moisture, pH, and mold counts were determined for each sample. No significant differences were detected in average bird weight, feed conversion, mortality, or condemnations. Litter moisture and pH values increased over the course of the experiment, whereas litter ash values showed no consistent trends. The highest mortality for birds on both litter types occurred in the first week of the experiment. However, the data suggest that when new litter is used for broilers, mortality is more evenly distributed over the grow-out period.

Six growers from each of five broiler companies were classified into equal numbers of good, mediocre, and poor growers based on a productivity index. Feed samples were collected weekly during the growout period of a flock from each grower and from the mill where the feed was produced. Samples of corn from which the feed was made were also collected. Aflatoxin, moisture contents, and bacterial, coliform, and fungal counts of the samples were determined. On the same weekly basis, the temperature and relative humidity of the chicken houses were measured and the age of the feed samples ascertained. Aflatoxin concentration in feed of good growers was 6.1 ppb with an 18.0% frequency of contamination while the values for poor growers were 14.0 ppb and 31.3%. Mean aflatoxin concentration in corn of 1.2 ppb increased to 8.8 ppb in feed from the farms. Optimum conditions for aflatoxin formation were 19 to 27 C, 79 to 89% relative humidity, and 10 to 13% moisture. Increasing age of feed was associated with low moisture and high aflatoxin. High aflatoxin was associated with high relative humidity but not with fungal, bacterial, or coliform counts. These data suggest that aflatoxin is produced during and after feed manufacture in apparently normal operations, that low levels of aflatoxin are associated with productivity losses in apparently healthy broilers, and that the aflatoxin formation is associated with high relative humidity in houses and with long residence time of the feed in the house. Because relative humidity and residence time in houses can be altered, aflatoxin formation might be limited by controlling these two factors.

Weekly composite feed samples were collected from three farms that had manually filled tube type feeders and three that had automatic pan type feeders. Feed from pan type feeders had four-fold higher fungal activity than did feed from tube type feeders. The data suggest that the ratio of surface area to feed weight was associated with this difference.

The efficacy of Endox®, 2,6-di-tert-butyl-4-methylphenol (BHT), and Ethoxyquin® for preservation of vitamin A was tested in three trials by placing four replicates of pelleted feed (ca. 27 kg each) in galvanized metal cans with tight-fitting lids. The vitamin premix used contained no antioxidant. After the feed was sampled, the cans were equipped with thermocouples and placed outside for 30 days. The data suggest that Endox® and Ethoxyquin® are equal in effectiveness and that both may be superior to BHT.

Twenty samples were collected before and after pelleting a 454-kg-lot of feed and assayed for vitamin A. Vitamin A assay levels were reduced 6.5% by pelleting at 80 C. The value reported here is one-fifth the value reported in 195 8 and 30% lower than the value recently reported.

Soybean meal samples were collected for analysis from 1976 through 1982 and analyzed for moisture, fat, protein, fiber, and urease. Moisture increased in almost linear fashion during this period. Values for fat recorded in 1981 and 1982 were significantly lower than those recorded earlier. Fiber values increased significantly in 1979, 1980, and 1981 and then decreased significantly in 1982. The urease data suggest that inadequately heat-treated soybean meal was more common in 1982 than in 1981.