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Intrinsic characteristics of fresh produce, such as pH, water activity, acid content and nutrient availability are critical factors in determining the survival and growth of Listeria monocytogenes (Lm). In this study, sterile fresh produce juice was used to analyze Lm growth potential among 14 different commodities and to identify physicochemical characteristics in those juices that affect Lm growth. Significant growth of Lm was observed in juices with pH ≥5.6 and low acidity (0.04-0.07 % titratable acidity (TA)) (cantaloupe, carrot, celery, green pepper, parsley, and romaine lettuce), slight reduction of Lm was observed in juices with pH 4.1 (tomato) and pH 3.9 (mango), and no Lm counts were recovered from juices with pH ≤3.8 and high acidity (0.28-1.17 % TA) (apple, blueberry, grape, peach, and pineapple). Although these acidic fruit juices possessed a high sugar content, the pH and acidity of produce juice seemed to be the primary determinants for Lm growth. The neutralization of acidic juices (i.e., Fuji and Gala apple, blueberry, grape, mango, pineapple, peach, and tomato) enabled Lm growth at 37 °C in all juices except for Gala apple and peach. Strong decline in Lm populations in Gala apple, grape and peach juices might be linked to sensitivity to organic acids, such as malic acid. Furthermore, Lm populations significantly decreased in pH-neutral (7.6) cauliflower juice, suggesting that potential antilisterial substances may play a role in Lm decline in cauliflower juice.

Listeria monocytogenes (Lm) outbreaks and recalls associated with fresh produce in recent years have heightened concerns and demands from industry and consumers to more effectively mitigate the contamination risk of this foodborne pathogen on fresh produce. In this study, the growth of Lm and indigenous bacteria on fresh-cut cantaloupe and romaine lettuce held at refrigerated (4 °C) and abusive (10-24 °C) temperatures was determined by both culture dependent and independent methods. Composition and dynamics of bacterial communities on Lm inoculated and non-inoculated samples were analyzed by 16S rRNA high-throughput sequencing. Fresh-cut cantaloupe provided favorable growth conditions for Lm proliferation (1.7 and6 log increase at refrigerated and abusive temperatures, respectively) to overtake indigenous bacteria. The Lm population also increased on fresh-cut lettuce, but the growth rate was lower than that of the total mesophilic bacteria, resulting in 0.4 and2 log increase at refrigerated and abusive temperatures. Microbial diversity of fresh-cut cantaloupe was significantly lower than that of fresh-cut romaine lettuce. The Shannon index of microbial communities on cantaloupe declined after storage, but it was not significantly changed on lettuce samples. Shifts in the bacterial microbiome on cantaloupe were mainly affected by Lm inoculation, while both inoculation and storage temperature played significant roles on lettuce bacterial communities. Multiple indigenous bacteria, including Leuconostoc and Weissella spp., were negatively correlated to Lm abundance on romaine lettuce, and were determined by bioassay as potential anti-listerial species. Data derived from this study contribute to better understanding of the relationship between Lm and indigenous microbiota on fresh-cut produce during storage.

An emerging poultry manure management practice is in-house windrowing to disinfect the litter. However, this practice is likely to increase emissions of ammonia (NH) and nitrous oxide (NO) from the windrowed litter. The objective of this study was to quantitatively compare NH and NO emissions from broiler houses with and without in-house windrowing. Two broiler houses at a commercial farm were used to compare the NH and NO emissions. Gas emission measurements were conducted continuously and simultaneously for both the control house (without windrowing) and the house with windrowing during the same production periods. The house emission rates were calculated by multiplying the hourly mean gas concentrations and the ventilation rates. The windrowed litter temperature was significantly higher than that of the control litter. The impact of downtime (the time lapse between flocks, during which the bird house is empty) windrowing litter on pathogen reduction was inconclusive because of very low or no recovery of both and spp. from control or windrowed litter samples, respectively. The windrowing house NH emissions were 26.2 and 16.6 kg d house, whereas for the control house, they were 14.6 and 12.8 kg d house in 2012 and 2013, respectively. The NO emissions from the windrowing house were also higher than those from the control house. The total NH and NO emissions from broiler houses practicing windrowing litter management were estimated to be 35.0 and 4.43 g bird, respectively, compared with 31.9 and 3.89 g bird for the control house, respectively.

Imported papayas from Mexico have been implicated in multiple salmonellosis outbreaks in the United States in recent years. While postharvest washing is a critical process to remove latex, dirt, and microbes, it also has the potential of causing cross-contamination by foodborne pathogens, with sponge or other fibrous rubbing tools often questioned as potential harboring or transmitting risk. In this study, Salmonella inactivation and cross-contamination via sponges and microfiber wash mitts during simulated papaya washing and cleaning were investigated. Seven washing treatments (wash without sanitizer; wash at free chlorine 25, 50, and 100 mg/L, and at peracetic acid 20, 40, and 80 mg/L), along with unwashed control, were evaluated, using Salmonella strains with unique antibiotic markers differentially inoculated on papaya rind (serovars Typhimurium, Heidelberg, and Derby) and on wash sponge or microfiber (serovars Typhimurium, Newport, and Braenderup). Salmonella survival and transfer on papaya and on sponge/microfiber, and in wash water were detected using selective plating or enrichment. The washing and cleaning process reduced Salmonella on inoculated papayas by 1.69–2.66 and 0.69–1.74 log for sponge and microfiber cleaning, respectively, with the reduction poorly correlated to sanitizer concentration. Salmonella on inoculated sponge or microfiber was under detection limit (1.00 log CFU/cm2) by plate count, but remained recoverable by selective enrichment. Transference of Salmonella from inoculated papaya to sponge/microfiber, and vice versa, could be detected sporadically by selective enrichment. Sponge/microfiber mediated Salmonella cross-contamination from inoculated to uninoculated papayas was frequently detectable by selective enrichment, but rendered undetectable by wetting sponge/microfiber in sanitizing wash water (FC 25–100 mg/L or PAA 20–80 mg/L) between washing different papaya fruits. Therefore, maintaining adequate sanitizer levels and frequently wetting sponge/microfiber in sanitizing wash water can effectively mitigate risks of Salmonella cross-contamination associated with postharvest washing, especially with regard to the use of sponge or microfiber wash mitts.

Washing is an essential postharvest processing step for reducing microbial populations, tissue latex fluids, and soil on fresh and fresh-cut produce. This study focuses on the performance of a novel in-flight washer (IFW) in which produce falls through a round vertical canister, equipped with an array of nozzles near its interior boundary, spraying a sanitizing liquid upward and radially inward so as to directly impact the falling produce. The spray retards downward motion of the produce, while reorienting it as it falls, thus improving contact between liquid and produce. Chopped iceberg lettuce was passed through an IFW, a flume system, or sequentially through both, with different free chlorine levels. Microbial reduction and quality parameters (sensory attributes and tissue membrane integrity) were evaluated on days 0, 7, and 14 of a 14-day storage period. When washed only in the IFW with 200 mg/L free chlorine (FC), 1.0 and 1.4 log reductions of inoculated E. coli were achieved on Days 0 and 14, respectively. These reductions are comparable to or greater than those achieved with only flume washing at 20 mg/L FC. Among all treatments, washing in IFW at 200 mg/L FC resulted in the lowest aerobic plate count and yeast and mold values, as well as the highest overall quality score. These results indicate that use of the IFW can improve postharvest food safety and quality of fresh-cut lettuce, compared to conventional flume washing.

A new treatment system was developed to meet multiple environmental performance standards including to substantially reduce ammonia emissions. It was tested full-scale for 2-years in a 5,145-head finishing swine farm with two anaerobic lagoons. The system combined high-rate solid-liquid separation with nitrogen and phosphorus removal processes. Both vertical radial plum mapping (VRPM) and floating static chamber techniques were used to measure NH3 emission fluxes from anaerobic storage lagoons and the total farm-level NH3 emission rates. The VRPM used an open-path tunable diode laser absorption spectroscopy (TDL) and the flux chamber used a photoacoustic gas analyzer to accurately measure NH3 concentration. After the treatment system started, one of the two lagoons became inactive without receiving anymore flushed manure. The ammonia emission flux from the other lagoon with the treated effluent decreased from 43.9 to 6.8 kg-N ha−1 d−1 1.5 years after implementation of the new treatment system. The NH3 emission flux from the inactive lagoon also decreased similarly because the already stored old manure of the lagoon prior to inactivation was diluted with rainfalls and lost some NH3 via volatilization. The total farm-level NH3 emission rates decreased from 1.72 g s−1 to below detection level of the VRPM technique. Using the minimum detection level of the TDL with R2 > 90% (i.e., 8.1 8.1 μL L−1-m), the total farm-level NH3 emission rates in the second year were less than 0.04–0.15 g s−1. These results suggested that the impact of the new treatment system on NH3 emission reduction was equivalent to closing conventional swine lagoons while actively growing 5,145 pigs with minimal ammonia emissions from the farm.

This study determined the water quality improvements in swine lagoons by an innovative swine manure treatment system operating at full-scale during five pig production cycles. The system performed high-rate solid-liquid separation, biological ammonia treatment and phosphorus treatment. Based on performance results obtained, it was determined that the treatment system met the technical environmental performance criteria for swine waste management systems in new or expanding operations in North Carolina. The system substantially reduced odor by 99.9%; pathogens by 99.99%, nutrients (phosphorus and nitrogen) by > 90%, and heavy metals by 99%. As the treated effluent and/or rainwater renovated the liquid in the anaerobic lagoons, they became aerobic (Eh > 300 millivolts). By the end of the second year, the NH4-N concentration in the lagoons liquid was reduced from the initial 370-485 mg L-1 to lower than 15. After conversion, the sludge accumulation in the former lagoons was halted. This was a significant outcome because one converted lagoon served twice the number of animals than before implementation of the innovative manure treatment system, which is similar to a situation of herd expansion. These findings overall showed that cleaner alternative technologies can have significant positive impacts on water quality in intensive swine production.

Spread of manure pathogens is of considerable concern due to use of manure for land application. In this study, the effects of four static pile treatment options for bovine manure on die-off of a generic Escherichia coli, E. coli O157:H7 surrogate, Salmonella Senftenberg, Salm. Typhimurium, and Listeria monocytogenes were evaluated. Bovine manure spiked with these bacteria were placed in cassettes at the top, middle, and bottom sections of four static pile treatments that reflect minimal changes in pile construction with and without straw. Temperatures were monitored continuously during the 28 day self-heating period. E. coli and salmonellae were reduced from 8 to 9 log10 CFU g(-1) to undetectable levels (

Bacterial pathogens may survive and regrow in finished compost due to incomplete thermal inactivation during or recontamination after composting. Twenty-nine finished composts were obtained from 19 U.S. states and were separated into three broad feedstock categories: biosolids (n=10), manure (n=4), and yard waste (n=15). Three replicates of each compost were inoculated with ≈ 1-2 log CFU/g of nonpathogenic Escherichia coli, Salmonella spp., and E. coli O157:H7. The U.S. Environmental Protection Agency's (EPA) protocols and U.S. Composting Council's (USCC) Test Methods for the Examination of Composting and Compost (TMECC) were compared to determine which method recovered higher percentages of inoculated E. coli (representing fecal coliforms) and Salmonella spp. from 400-g samples of finished composts. Populations of Salmonella spp. and E. coli O157:H7 were determined over 3 days while stored at 25°C and compared to physicochemical parameters to predict their respective regrowth potentials. EPA Method 1680 recovered significantly (p=0.0003) more inoculated E. coli (68.7%) than TMECC 07.01 (48.1%) due to the EPA method using more compost in the initial homogenate, larger transfer dilutions, and a larger most probable number scheme compared to TMECC 07.01. The recoveries of inoculated Salmonella spp. by Environmental Protection Agency Method 1682 (89.1%) and TMECC 07.02 (72.4%) were not statistically significant (p=0.44). The statistically similar recovery percentages may be explained by the use of a nonselective pre-enrichment step used in both methods. No physicochemical parameter (C:N, moisture content, total organic carbon) was able to serve as a sole predictor of regrowth of Salmonella spp. or E. coli O157:H7 in finished compost. However, statistical analysis revealed that the C:N ratio, total organic carbon, and moisture content all contributed to pathogen regrowth potential in finished composts. It is recommended that the USCC modify TMECC protocols to test larger amounts of compost in the initial homogenate to facilitate greater recovery of target organisms.

In this research, a multispectral fluorescence-based imaging algorithm was developed to detect frass contamination on mature Campari tomatoes. Tomato images were acquired using a hyperspectral fluorescence line-scan imaging system with violet LED excitation, then analyzed for wavelength selection. The fluorescence intensities at five wavelengths, 515 nm, 640 nm, 664 nm, 690 nm, and 724 nm, were used to compute three simple ratio functions to detect frass contamination. The contamination spots were created on the tomato surfaces using four low-concentration frass dilutions. The algorithms detected over 99% of the 0.2 kg/L and 0.1 kg/L frass contamination spots and successfully differentiated these spots from tomato skin surfaces, stem scars, and stems. However, differentiation of the 0.05 kg/L and 0.02 kg/L frass contamination spots was more difficult. Adjusting the algorithm to successfully detect 95% of the 0.05 kg/L spots also resulted in false-positive pixel detections occurring on 28% of the tomatoes. This study demonstrates that a simple multispectral fluorescence imaging algorithm based on violet LED excitation could be useful for rapid postharvest detection of frass contamination on tomatoes in processing lines.

Two rapid immunomagnetic separation (IMS) protocols were evaluated to recover inoculated Escherichia coli O157:H7 (1–2 log colony-forming unit (CFU)/g) from 30 different commercial, finished compost samples. Both protocols detected E. coli O157:H7 in compost samples; PCR techniques required the removal of inhibitors to reduce possibility of a false negative result.

Outbreaks associated with leafy greens have focused attention on the transfer of human pathogens to these commodities during harvest with commercial equipment. Attachment of Escherichia coli O157:H7 on new or rusty spinach harvester blades immersed in spinach extract or 10% tryptic soy broth (TSB) was investigated. Bacteriophages specific for E. coli O157:H7 were evaluated to kill cells attached to blade. A cocktail of five nalidixic acid-resistant E. coli O157:H7 isolates was transferred to 25 mL of spinach extract or 10% TSB. A piece of sterilized spinach harvester blade (2×1") was placed in above spinach extract or 10% TSB and incubated at room (22 °C) or dynamic (30 °C day, 20 °C night) temperatures. E. coli O157:H7 populations attached to blade during incubation in spinach extract or 10% TSB were determined. When inoculated at 1 log CFU/mL, E. coli O157:H7 attachment to blades after 24 and 48 h incubation at dynamic temperature (6.09 and 6.37 log CFU/mL) was significantly higher than when incubated at 22 °C (4.84 and 5.68 log CFU/mL), respectively. After 48 h incubation, two blades were sprayed on each side with a cocktail of E. coli O157-specific bacteriophages before scraping the blade, and subsequent plating on Sorbitol MacConkey media-nalidixic acid. Application of bacteriophages reduced E. coli O157:H7 populations by 4.5 log CFU on blades after 2 h of phage treatment. Our study demonstrates that E. coli O157:H7 can attach to and proliferate on spinach harvester blades under static and dynamic temperature conditions, and bacteriophages are able to reduce E. coli O157:H7 populations adhered to blades.

Aims: Survival of Escherichia coli O157:H7 and nonpathogenic E. coli on spinach leaves and in organic soil while growing spinach in a growth chamber was investigated. Methods and Results: Spinach plants were maintained in the growth chamber at 20°C (14 h) and 18°C (10 h) settings at 60% relative humidity. Five separate inocula, each containing one strain of E. coli O157:H7 and one nonpathogenic E. coli isolate were applied to individual 4-week-old spinach plants (cultivar ‘Whale’) grown in sandy soil. Leaf and soil inocula consisted of 100 μl, in 5 μl droplets, on the upper side of leaves resulting in 6·5 log CFU plant−1 and 1 ml in soil, resulting in 6·5 log CFU 200 g−1 soil per plant. Four replicates of each plant shoot and soil sample per inoculum were analysed on day 1 and every 7 days for 28 days for E. coli O157:H7 and nonpathogenic E. coli (by MPN) and for heterotrophic plate counts (HPC). Escherichia coli O157:H7 was not detected on plant shoots after 7 days but did survive in soil for up to 28 days. Nonpathogenic E. coli survived up to 14 days on shoots and was detected at low concentrations for up to 28 days. In contrast, there were no significant differences in HPC from days 0 to 28 on plants, except one treatment on day 7. Conclusions: Escherichia coli O157:H7 persisted in soil for at least 28 days. Escherichia coli O157:H7 on spinach leaves survived for less than 14 days when co-inoculated with nonpathogenic E. coli. There was no correlation between HPC and E. coli O157:H7 or nonpathogenic E. coli. Significance and Impact of the Study: The persistence of nonpathogenic E. coli isolates makes them possible candidates as surrogates for E. coli O157:H7 on spinach leaves in field trials.

The aim of this study was to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy cow wastewater using solid-liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy cow manure of varied strengths - 0.4%, 0.8%, 1.6%, and 3.2% total solids (TS) content. Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective; average efficiencies were about 60% for total suspended solids (TSS), 22% for total Kjeldahl nitrogen (TKN), and 26% for total phosphorus (TP). Mixing with chitosan before screening substantially increased separation. At optimum chitosan rate (0.5g/L for the highest strength effluent), separation efficiencies were >95% for TSS, >73% for TKN, and >54% for TP. The results of this study indicate that natural flocculants such as chitosan are useful for the solid-liquid separation treatment of livestock wastewater.

Oxytetracycline (OTC) and chlortetracycline (CTC) are broad-spectrum antibiotics used in livestock production. Although laboratory-scale studies have shown that extractable concentrations of these compounds decrease over time within treated and untreated manures and soils, there is relatively little information from farm-scale experiments. The objective of this study was to determine the effect of different levels of management on manure pile temperature profiles and on the fate of OTC and CTC in manure from therapeutically treated calves. Four treatments were designed to span a range of management options - from simply piling up the manure to amending it with straw to increase aeration and adding insulating layers of straw. Replicate samples of antibiotic-containing calf manure were held at ambient temperature or placed in three locations within replicate 3m(3) piles of beef manure. During the 28-day incubation period, concentrations of buffer-extractable OTC and CTC/ECTC (the summed concentrations of CTC and its epimer 4-epi-chlortetracycline (ECTC)) in manure samples incubated at ambient temperature (11-24 degrees C) decreased 75% (from 18 to 4.6 mg kg(-1) dry weight (DW)) and 90% (from 192 to 16 mg kg(-1) DW), respectively. Concentrations of the CTC metabolite iso-chlortetracycline (ICTC) decreased 90% (from 37 to 3 mg kg(-1) DW). OTC and CTC/ECTC concentrations in samples incubated for 28 days within a non-amended manure pile decreased 91% and99%, respectively. During that period, the manure pile temperature ranged from 36 degrees C to 45 degrees C. Manure piles insulated with a blanket of straw and/or amended with straw (3:1, v/v) attained temperatures up to 70 degrees C and contained very low levels of OTC, CTC/ECTC, and ICTC (ranging from0.1 to 0.4 mg kg(-1) DW) after 28 days.

High tunnels and protected horticultural structures provide organic and conventional growers with an economic means for extending the harvest season of fresh fruits and vegetables in a wide range of climate zones in North America and elsewhere. This report focuses on benefits associated with high tunnel production of fresh organic produce, including recent data on phytonutrient quality. In addition, this report discusses concerns and knowledge gaps associated with the use of composts and manures relative to food safety of fresh produce and survival of enteric pathogens in the moist, cool, reduced ultraviolet conditions often prevalent in high tunnels during cool-season production. The role of preplant and production elements of Good Agricultural Practices and Good Handling Practices applicable to high tunnel systems is provided.

Bill had suffered severe trauma, the type of injury even a 46-year-old healthy man does not survive. A helicopter transferred Bill to tertiary trauma facility miles from his home. Nurses and physicians worked for hours to stabilize him. Throughout the day, family members arrived, some in tears, some angry, all confused and distraught over Bill's tragic accident. The afternoon of Bill's arrival, the physician had a meeting with the family. The physician was honest, direct, and compassionate with the family. Bill would not likely survive this trauma; however, he discussed the supportive process of comfort care. The family wrestled with their emotions and with the reality of Bill's eminent death for several hours. The family finally agreed to stop the futile treatments and allow Bill to experience a peaceful death. The comfort care protocol for Bill involved continuing mechanical ventilation, continuous intravenous sedation, and pain medications. Family members took turns in their vigil at Bill's bedside, each coping in his/her own way and toward his/her own acceptance of Bill's death, some in tears, some still angry at the unfairness of life. Bill was still alive the next morning, and the nurse from the day before resumed his care. The family's emotional journey culminated that morning with Bill's death, with loved ones surrounding his bedside, holding hands, and singing hymns as Bill's heart rate slowed and eventually stopped. There were tears in everyone's eyes, but there was also relief on their faces. Death had finally come, and Bill had never exhibited any signs of pain or suffering. No death is easy, but we all hope to die peacefully, with our loved ones surrounding us, comforted by each other's presence, and the knowledge that the right decision has been made.

A novel wash aid, T-128, was evaluated for its capacity to enhance the efficacy of chlorine solution for tomato washing against Salmonella enterica in the presence of high organic load. Incremental amount of tomato juice was added to chlorinated wash solutions to simulate free chlorine depletion during tomato washing operations. Cells of S. enterica were either directly inoculated into the wash solutions or onto the tomatoes that are washed in chlorinated solutions with or without T-128. Salmonella cells survived in the wash solution, in the stem-scar areas, and in the internal tissues of tomatoes were enumerated. Application of T-128 significantlyreduced the survival of Salmonella in chlorinated water when free chlorine approached depletion. It also resulted in a significantly higher reduction of S. entericapopulation on stem scars compared to the control. When inoculated and non-inoculated tomatoes were washed together, cross contamination by Salmonella cells to the non-inoculated tomatoes were reduced in the presence of T-128. The application of T-128 also significantly improved the chlorine efficacy against Salmonella internalization when chlorine concentration was near depletion. These results indicated that T-128 has the potential to improve chlorine efficacy against pathogen survival, cross-contamination and internalization in the wash solution when chlorine neared depletion, thus improve the safety margin of the process control.

A study was done to determine if a free-living, bacterivorous nematode, Caenorhabditis elegans, migrates to bovine manure, turkey manure, composted bovine manure, composted turkey manure, and manure-amended soil inoculated with Salmonella Newport. Movement of the worm to lettuce, strawberries, and carrots was also studied. C. elegans moved most rapidly to turkey manure and strawberries, with 35% and 60% of worms, respectively, associating with samples within 30 min. Survival and reproduction of C. elegans in test materials were not affected by the presence of S. newport. Bovine manure and bovine manure compost inoculated with S. newport (8.6 log10 CFU/g) were separately placed in the bottom of a glass jar and covered with a layer of soil (5 cm) inoculated (50 worms/g) or not inoculated with C. elegans. A piece of lettuce, strawberry, or carrot was placed on top of the soil before jars were sealed and held at 20 -C for up to 10 days. In the system using soil inoculated with C. elegans, S. newport initially in bovine manure was detected on the surface of lettuce, strawberry, and carrot samples within 3, 1, and 1 days, respectively. The pathogen was detected on lettuce, strawberry, and carrot within 1, 7, and 1 days, respectively, when initially present in bovine manure compost. With one exception, the pathogen was not detected on the produce over the 10-day incubation period when C. elegans was not present in the soil. Results indicate that C. elegans has the potential for transporting S. newport in soil to the surface of preharvest fruits and vegetables in contact with soil. D 2005 Elsevier B.V. All rights reserved.

A study was undertaken to determine the persistence of Escherichia coli O157:H7 and salmonellae in the gut of a free-living nematode, Caenorhabditis elegans, as affected by temperature and relative humidity and to determine if infected worms transmit Salmonella enterica serotype Newport to progeny and uninfected worms. Worms were fed cells of a non-pathogenic strain of E. coli (OP50), E. coli O157:H7, S. enterica serotype Newport, and S. enterica serotype Poona, followed by incubating at 4, 20, or 37 degrees C for up to 5 days. Initial populations of ingested pathogens significantly increased by up to 2.93 log(10) cfu/worm within 1 day at 20 degrees C on K agar and remained constant for an additional 4 days. When worms were placed on Bacto agar, populations of ingested pathogens remained constant at 4 degrees C, decreased significantly at 20 degrees C, and increased significantly at 37 degrees C within 3 days. Worms fed E. coli OP50 or S. Newport were incubated at 4 or 20 degrees C at relative humidities of 33%, 75%, or 98% to determine survival characteristics of ingested bacteria. Fewer cells of the pathogens survived incubation at 33% relative humidity compared to higher relative humidities. Populations of ingested E. coli OP50 and S. Newport decreased by up to 1.65 and 3.44 log(10) cfu/worm, respectively, in worms incubated at 20 degrees C and 33% relative humidity. Placement together on K agar of adult worms, labeled with green fluorescent protein (gfp) in the pharynx area, that had ingested gfp-labeled S. Newport and uninfected wild type worms resulted in transfer of the pathogen to gut of wild type worms. S. Newport was isolated from C. elegans two generations removed from exposure to the pathogen. Results of these studies show that C. elegans may serve as a temporary reservoir of foodborne pathogens, and could perhaps be a vector for contaminating preharvest fruits and vegetables, thus potentially increasing the risk of enteric infections associated with consumption of raw produce.

Many foodborne outbreaks of enterohemorrhagic Escherichia coli O157:H7 infection have been associated with the consumption of contaminated vegetables. On-farm contaminations through contaminated manure or irrigation water application were considered likely sources of the pathogen for several outbreaks. Field studies were done to determine the survival of E. coli O157:H7 on two subterranean crops (carrots and onions), and in soil fertilized with contaminated manure compost or irrigated with contaminated water. Three different types of composts, PM-5 (poultry manure compost), 338 (dairy manure compost) and NVIRO-4 (alkaline stabilized dairy manure compost), and irrigation water were inoculated with an avirulent strain of E. coli O157:H7 at 107 cfu g−1 and 105 cfu ml−1, respectively. A split-plot block design plan was used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but with contaminated irrigation water applied) and five replicates for a total of 25 plots, each measuring 1.8×4.6 m2, for each crop. Composts were applied to soil as a strip at a rate of 4.5 metric tons ha−1 before carrots and onions were sown. Contaminated irrigation water was sprayed once on the vegetables at the rate of 2 l per plot for this treatment 3 weeks after carrots and onions were sown. E. coli O157:H7 survived in soil samples for 154–196 days, and was detected for 74 and 168 days on onions and carrots, respectively. E. coli O157:H7 survival was greatest in soil amended with poultry compost and least in soil containing alkaline-stabilized dairy manure compost. Survival profiles of E. coli O157:H7 on vegetables and soil samples, contaminated either by application of contaminated compost or irrigation water, were similar. Hence, preharvest contamination of carrots and onions with E. coli O157:H7 for several months can occur through both contaminated manure compost and irrigation water.

Three different types of compost, PM-5 (poultry manure compost), 338 (dairy cattle manure compost), and NVIRO-4 (alkaline-pH-stabilized dairy cattle manure compost), and irrigation water were inoculated with an avirulent strain of Salmonella enterica serovar Typhimurium at 10 7 CFU g −1 and 10 5 CFU ml −1 , respectively, to determine the persistence of salmonellae in soils containing these composts, in irrigation water, and also on carrots and radishes grown in these contaminated soils. A split-plot block design plan was used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but with contaminated water applied) and five replicates for a total of 25 plots for each crop, with each plot measuring 1.8 × 4.6 m. Salmonellae persisted for an extended period of time, with the bacteria surviving in soil samples for 203 to 231 days, and were detected after seeds were sown for 84 and 203 days on radishes and carrots, respectively. Salmonella survival was greatest in soil amended with poultry compost and least in soil containing alkaline-pH-stabilized dairy cattle manure compost. Survival profiles of Salmonella on vegetables and soil samples contaminated by irrigation water were similar to those observed when contamination occurred through compost. Hence, both contaminated manure compost and irrigation water can play an important role in contaminating soil and root vegetables with salmonellae for several months.

There are many sources of pathogen contamination of vegetable crops in the field that include manure used as fertilizer and irrigation water. An avirulent strain of Salmonella enterica serovar Typhimurium was added to three different types of composts-PM-5 (poultry manure compost), 338 (dairy manure compost), and NVIRO-4 (alkaline stabilized dairy manure compost)-and irrigation water at 10(7) colony forming units (cfu)/g and 10(5) cfu/mL, respectively, to determine under field conditions the persistence of salmonellae in soils treated with these composts or irrigation water, and also on leaf lettuce and parsley grown on such treated soil. Contaminated compost was applied to soil in the field as a strip at a rate of 4.5 metric tons/hectare on the day before lettuce and parsley seedlings were transplanted. Contaminated irrigation water was applied only once on the plants at the rate of 2 liters per plot on the same day after the seedlings were transplanted. Twenty-five plots, each measuring 1.8 x 4.6 meters, were used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but applied with contaminated water) and five replication plots for each treatment. Salmonella persisted for 161 and up to 231 days in soils amended with contaminated composts on which lettuce and parsley, respectively, were grown, and was detected for up to 63 days and 231 days on lettuce and parsley, respectively. The type of contaminated compost had minimal effect on the persistence of S. Typhimurium in soil. Occurrence of Salmonella on vegetables and survival in soil on which these vegetables were grown, irrespective of source of contamination through irrigation water or compost, were similar, suggesting both contaminated manure compost and irrigation water can play important roles in contaminating soil and vegetables with Salmonella for an extended period of time.

Near-infrared spectroscopy (NIRS) and mid-infrared spectroscopy (MIRS) have been used for quantitative and/or qualitative analysis of a wide range of materials. The objective of this study was to investigate the potential of MIRS and NIRS for following the degradation of bio-based food utensils during composting. Polylactide (PLA)-based forks lost 34% of their initial mass and were reduced to small friable fragments after 7 weeks of composting. NIRS and MIRS spectra of forks that were incubated for 7 weeks were nearly identical to spectra of untreated forks. NIRS and MIRS were more useful in following the degradation of a starch/polypropylene (PP) polymer. Spectral results demonstrated that the starch component degraded during composting and that the PP component was recalcitrant. These results confirm that MIRS and NIRS are useful in determining the composition of biobased materials. However, the spectra did not provide useful information about the extent of PLA polymer degradation.

Salmonella can survive in soil for months to years; consequently, soil can be a preharvest source of contamination of produce. Elimination of Salmonella with natural products and processes such as essential oils is important to prevent infection among consumers. Essential oils (distilled extract from plants) have been mainly evaluated in liquid medium and foods in which minimum inhibitory concentration is determined. However, there are no reports describing the impact of essential oils in soil, especially organic soil. We evaluated essential oils for controlling Salmonella enterica serovars in organic soil. Two essential oils (cinnamaldehyde and eugenol), two bio-pesticides (Ecotrol and Sporan), and an organic acid (20% acetic acid) at 0.5%, 1.0%, 1.5%, and 2.0% were mixed with organic sandy soil and inoculated with six different serovars of S. enterica separately. Soils were incubated at room temperature, and samples obtained at 1, 7, and 28 days were enumerated to determine survival. The bactericidal effect of cinnamaldehyde was evident at 0.5%, 1.0%, 1.5%, and 2.0% and during all times of incubation. Overall, Salmonella Negev was the most sensitive strain to oils resulting in significant reductions compared with other strains. Increases in oil concentration resulted in further reduction of Salmonella with all oils used in the study. Up to six log reductions in Salmonella serovars Typhimurium, Negev, and Newport were found after 1 day when cinnamaldehyde, Ecotrol, eugenol, Sporan, or acetic acid was used at 2% level. This study shows the potential use of essential oils to effectively reduce Salmonella populations in soil. The significant reduction of Salmonella could greatly reduce potential contamination of fresh organic produce inadvertently contaminated by soil.

The effect of cultivation practices for controlling strawberry black root rot (BRR) on fruit quality, antioxidant capacity, and flavonoid content in two strawberry cultivars Allstar and Chandler (Fragaria x ananassa Duch.) was evaluated. Strawberry fruits used in this study were from plants grown in soils which had a prior history of BRR and red stele, and had not been fumigated during the seven years prior to the study. Results from this study showed that fruit from plants grown in compost socks had significantly higher oxygen radical absorbance capacity (ORAC), flavonoids, anthocyanins, soluble solids content (SSC), titratable acid (TA), fructose, glucose, sucrose, malic acid, and citric acid than fruit produced in the black plastic mulch or matted row systems. Cultivar Chandler surpassed cv. Allstar in sugar content, acid content, and flavonoid content regardless of preplanting vinegar drenching and various culture treatments. However, preplanting vinegar treatment increased cyanidin-based and pelargonidin-based anthocyanins but decreased sugar content in fruits of both cultivars.

A rapid nondestructive technology is needed to detect bacterial contamination on the surfaces of food processing equipment to reduce public health risks. A portable hyperspectral fluorescence imaging system was used to evaluate potential detection of microbial biofilm on stainless steel typically used in the manufacture of food processing equipment. Stainless steel coupons were immersed in bacterium cultures, such as E. coli, Pseudomonas pertucinogena, Erwinia chrysanthemi, and Listeria innocula. Following a 1-week exposure, biofilm formations were assessed using fluorescence imaging. In addition, the effects on biofilm formation from both tryptic soy broth (TSB) and M9 medium with casamino acids (M9C) were examined. TSB grown cells enhance biofilm production compared with M9C-grown cells. Hyperspectral fluorescence images of the biofilm samples, in response to ultraviolet-A (320 to 400 nm) excitation, were acquired from approximately 416 to 700 nm. Visual evaluation of individual images at emission peak wavelengths in the blue revealed the most contrast between biofilms and stainless steel coupons. Two-band ratios compared with the single-band images increased the contrast between the biofilm forming area and stainless steel coupon surfaces. The 444/588 nm ratio images exhibited the greatest contrast between the biofilm formations and stainless coupon surfaces.

To be permitted, new swine waste management systems in North Carolina need to meet the strict performance standards of an environmentally superior technology (EST). These technologies must be able to substantially remove nutrients, heavy metals, emissions of ammonia, odors, and pathogens. Our objective was to demonstrate, at full-scale, a second generation treatment system for swine waste that can achieve the high treatment performance standards of an EST, yet it is four times more economical than earlier versions. The system combines solid-liquid separation, biological ammonia treatment, and phosphorus removal and produces a deodorized and disinfected liquid effluent. The second generation system was installed full-scale in a 5,150-head finishing swine operation and demonstrated under steady-state conditions and cold and warm weather. The system removed 98% of the suspended solids, 100% of biological oxygen demand, 97% of the ammonia, 94% of the phosphorus, 99% of the copper and zinc, 99.9% of the odor compounds, and reduced pathogens 4-logs (99.99%). Ammonia concentration in the air of the barns was significantly reduced, and animal health and productivity were enhanced. Compared to the traditional lagoon management, the animal mortality decreased 57%, the rate of daily weight gain increased 11%, and the rate of feed conversion into meat improved 5.4% with the new manure management system. These findings showed that two or more simple processes can be combined into a practical system to achieve the strict EST performance standards and that these cleaner technologies can have significantly positive impacts on animal productivity and the environment.

In this study, hyperspectral fluorescence imaging techniques were investigated for detection of microbial biofilm on stainless steel plates typically used to manufacture food processing equipment. Stainless steel coupons were immersed in bacterium cultures of nonpathogenic E. coli, Pseudomonas pertucinogena, Erwinia chrysanthemi, and Listeria innocua. Following a 1-week growth in rich medium tryptic soy broth (TSB) and M9 minimal medium with casamino acids (M9C), biofilm formations were evaluated using a recently developed portable hyperspectral fluorescence imaging system. Hyperspectral fluorescence images of the biofilm samples, in response to ultraviolet-A (320 to 400 nm) excitation, were acquired from 416 to 700 nm. Fluorescence images in the blue emission peak region exhibited the most contrast between biofilms and stainless steel coupons. On the basis of correlation analyses, two-band ratios compared with the single-band images enhanced the contrast between the biofilm forming area and untreated coupon surfaces. A two-band fluorescence ratio image, 444/588 nm, resulted in the greatest contrast between the biofilm formations and stainless steel coupon for the biofilms grown in M9C medium. TSB medium showed relatively high auto-fluorescence, and thus further investigation is needed to mitigate the contribution of strong TSB auto-fluorescence in detection of biofilms.

Liquid-solid separation treatment can solve many environmental problems associated with confined livestock production. However, treatment technologies are needed to transform the separated manure solids into value-added products. Our objective was to demonstrate, at full-scale, the composting of separated swine manure solids using a centralized solids processing facility. In this facility, the solids were combined with cotton gin waste and wood chips to optimize the composting process. The produced composts conserved 95-100% of the nitrogen and other nutrients and met EPA Class A biosolids quality standards due to low pathogen levels. The composts were used for manufacture of soil amendments, organic fertilizers, and potting soil. Results from this project have demonstrated that manure and other agricultural wastes can be transformed into valueadded products using a simple and effective technology.

Little attention has been paid to the environmental fate of the hormones 17beta-estradiol and testosterone excreted in animal waste. Land application of manure has a considerable potential to affect the environment with these endocrine disrupting compounds (EDCs). Composting is known to decompose organic matter to a stable, humus-like material. The goal of the present study was to quantitatively assess levels of water-soluble 17beta-estradiol and testosterone in composting chicken manure with time. Chicken layer manure was mixed with hay, straw, decomposed leaves, and starter compost, adjusted to approximately 60% moisture, and placed into a windrow. A clay-amended windrow was also prepared. Windrows were turned weekly, and temperature, oxygen, and CO(2) in the composting mass were monitored for either 133 or 139 d. Commercial enzyme immunoassay kits were used to quantitate the levels of 17beta-estradiol and testosterone in aqueous sample extracts. Water-soluble quantities of both hormones diminished during composting. The decrease in 17beta-estradiol followed first-order kinetics, with a rate constant k = -0.010/d. Testosterone levels declined at a slightly higher rate than 17beta-estradiol (i.e., k = -0.015/d). Both hormones could still be measured in aqueous extracts of compost sampled at the conclusion of composting. The decline in water-soluble 17beta-estradiol and testosterone in extracts of clay-amended compost was not statistically different from normal compost. These data suggest that composting may be an environmentally friendly technology suitable for reducing, but not eliminating, the concentrations of these endocrine disrupting hormones at concentrated animal operation facilities.

The environmental and economic incentives to recycle and recover useful resources from various organic materials, such as animal manures, biosolids, landscape trimmings and food processing and marketing residuals, continue to increase. The same incentives are stimulating interest among scientists, horticulturists, entrepreneurs, and the minerals industries in the potential for utilization of various inorganic by-products, from cement, rock, aggregate, power plant and steel manufacturing operations, as beneficial additives to these organics. The resulting ‘bio-mineral’ products will provide stabilized organic materials augmented with mineral components useful in agriculture, horticulture, landscaping and reclamation. Some form of treatment will be required to remove pathogenic organisms that are present in primary organic constituents of such bio-mineral products. Existing federal standards (“40CFR503 for Code of Federal Regulations”) for biosolids include criteria for assessing pathogen destruction achieved by several treatment processes. The applicability and appropriateness of these criteria to organic and bio-mineral products, not containing biosolids, is discussed along with the need for test refinements appropriate to new technologies. Potential disease transmission pathways and case reports involving emerging pathogens, e.g., E. coli O157:H7, salmonellae, Cryptosporidium parvum, suggest that environmental health implications of farm and food production practices involving animal manure be reviewed and evaluated in a manner equivalent to that of biosolids. Specific information on pathogen survival and destruction relative to current and developing organics and bio-minerals recycling processes is needed to support development of guidelines for appropriate practices. Depending on the treatment process and the targeted mineral composition of the final product, inorganic constituents may be added prior to, during, or after organics processing. The sequence of mineral augmentation in organics processing has the potential to influence the quality of the product, but more research is urgently needed to optimize these benefits and to support recommendations that promote environmental and public health.

Afield study of organic production of tomato (Lycopersiconesculentum Mill.) in high-tunnels was conducted in 2004. `Mountain Fresh' was transplanted 31 Mar.; `Ultra Sweet' and `Sun Leaper' were transplanted on 21 July. The primary objective was to determine the feasibility of obtaining two crops of fresh-market tomatoes by starting plants 4–8 weeks earlier than the average last spring-killing frost, and extending the growing season 4–6 weeks past the average first fall-killing frost. Plants were started at weekly intervals for 4 weeks in both seasons. Data and observations were recorded on the yield of marketable fruits, plant growth and development, and plant health. Other objectives were to evaluate: 1) the benefits of using a selective UV-blocking film on plant growth and development, disease events; and 2) compost amendments on soil improvement and disease control. Major cultural challenges included water management, soil texture/drainage, prevention of chilling injury, plant support, and adequate ventilation. Major disease/pest challenges involved stalk rot caused by Sclerotinia sclerotiorum in the spring, powdery mildew in spring and late summer, Alternaria and Septoria leaf blight in late summer, and aphids, tomato hornworm, corn earworm, and beet army worm also in late summer. In addition, macrofaunal intrusions by fox, mice, and birds occurred sporadically. Poor drainage and stalk rot in the spring necessitated relocating the tunnels to an uninfested site with better drainage. The fall crop yielded high numbers of marketable quality fruits, well beyond the 15 Oct. average killing frost date. The results suggest that with improved management, there is a considerable potential for profitable extended-season production of organic tomatoes in this region.