Food Safety Pathogen Research Articles

A new protein source for pet food: cultivated meat

Cultivated meat is an alternative protein source developed to address the sustainability, public health and animal welfare concerns of conventional meat production. Hundreds of startups and academic institutions worldwide are working to make cultivated meat a cost-effective protein source for humans. However, cultivated meat could also be used to feed dogs and cats, contributing to solving the meat supply issues that the growing pet food market has been facing in recent years. The advantages of using cultivated meat as a protein source for pets would include a reduction of the environmental impact of pets’ diets, decreased farm animal suffering and several benefits in the One Health framework, as cultivated meat-based pet food would significantly decrease the risk of spreading food safety pathogens, zoonotic diseases and resistant bacteria. The antibiotic-free manufacturing process and the aseptic conditions the cells require to grow in the bioreactors lead to these public health advantages. However, cultivated meat has never been produced at scale for human or pet consumption. Several technical challenges need to be overcome to make cultivated meat-based pet food prices accessible to consumers. As a novel ingredient, there is also no evidence of the effect of feeding cultivated meat to dogs and cats. In principle, cultivated meat can be both safe to be consumed long-term and nutritionally adequate – and with several possibilities for nutritional enhancement, potentially even superior to its conventional counterpart. However, the safety and nutritional soundness of cultivated meat-based products must be demonstrated by manufacturers to gain regulatory approval and favour consumer adoption. Veterinarians, veterinary nurses and technicians will play a critical role in the development of this new ingredient in many aspects, including product development, assessing safety and nutrition, conducting research and informing consumers. This review summarises the benefits and challenges of using cultivated meat as a pet food ingredient.

Paclobutrazol Residues in Recirculated Water in Commercial Greenhouses

Reusing irrigation water has technical, environmental, and financial benefits. However, risks are also associated with the accumulation of agrochemicals, in addition to ions, plant and food safety pathogens, and biofilm organisms. In this project, we measured the concentration of paclobutrazol (a persistent and widely used plant growth regulator) in recirculated water in greenhouses producing ornamental plants in containers. Solutions were collected from catchment tanks at nine commercial greenhouses across seven states in the United States in Spring and Fall 2014. Paclobutrazol was detected in all samples, with differences observed by season, greenhouse operation, paclobutrazol application method, and irrigation method. Across operations, the residual concentration of paclobutrazol was higher in spring for most greenhouses (ranging from 0 to 1100 µg·L−1) compared with the fall (ranging from 0 to 8 µg·L−1). The spray-drench application method resulted in the highest residual concentrations (up to 35 µg·L−1), followed by substrate drench (up to 26 µg·L−1) and foliage spray (concentrations under 3 µg·L−1). Residual concentrations were higher with overhead irrigation (up to 35 µg·L−1) compared with subirrigation systems (up to 15 µg·L−1). Our results indicate that paclobutrazol is likely to be a growth retardant risk in greenhouse operations recirculating water. A clear understanding of the risks associated with recirculated water intends to support the development and implementation of risk management strategies to ensure and promote safe use of recirculated water in greenhouses. Overall, the most effective preventative strategy is to ensure the use of the minimum amount of the a.i. necessary per unit of space and time.

Impedance In Vitro Assessment for the Detection of Salmonella typhimurium Infection in Intestinal Human Cancer Cells

A significant number of research papers regarding biosensor-related assays for key food safety pathogens based on the use of mammalian cells has been reported. In this study, the Salmonella typhimurium infection progression was monitored in the human colon cancer cell line Caco-2 and the mucus-secreting HT29-MTX-E12, after treatment with five different bacterial MOI for 30 min by comparing the alterations of frequencies recordings with impedance spectroscopy measurements. For this purpose, bacterial adhesion and invasion assays were initially performed. Then, the data obtained from impedance spectroscopy recordings were compared to cell viability data derived from the MTT uptake cell proliferation assay as well as from live cell analysis assays of mitochondrial membrane potential alterations. From our findings a concentration-dependent increase in bacterial colonies occurring from invaded cells was observed upon a higher multiplicity of infection (MOI) bacterial infection at both cell lines. On the contrary, the bacteria infection did not have any impact on the viability of the cells after 1 h of treatment. Differential results were obtained from the measurement of mitochondrial potential at both cell lines. Finally, the impedance values recorded from the 2D, and 3D cultures were concentration-dependent for both cell lines whereas a characteristic pattern specific to each cell line was revealed. Our results indicate that human cell-based bio-electric assays can be a valuable tool for obtaining a unique fingerprint for each bacterial infection in the near future.

Lactic acid bacteria metabolites in fish feed additives inhibit potential aquatic and food safety pathogens growth, and improve feed conversion

ABSTRACT The fermented broth of lactic acid bacteria (LFB)was the side product while lactic acid bacteria produced; however, it was abundant of antimicrobial activity. That might be a good candidate for feed additive in aquaculture. In this study, the fermented broth of Lactobacillus paracasei GL-156, the most antibacterial activity, was further evaluated the safety, growth performance gut microbiota. Common carp consumed the feed in dose of 1000 ppm LFB, the survival was no significant different with control group, but the growth performance was significant increased. In the intestine microbiota analysis, the treatment fish shown the decrease of vibrio, but no different of total bacterial count. These results demonstrate the LFB from GL-156 in enhancing the growth performance, inhibiting the growth of pathogenic bacteria, and promoting the growth of probiotic organisms. Compare with live probiotics currently used in aquaculture, using LFB will achieved beneficial effects equally, while providing superior tolerance to manufacturing processes, and in the lower cost.

Conserved CRISPR arrays in Salmonella enterica serovar Infantis can serve as qPCR targets to detect Infantis in mixed serovar populations.

Salmonellosis is a leading bacterial cause of foodborne illness, and numerous Salmonella enterica serovars have been responsible for foodborne outbreaks. In the United States outbreaks are often linked to poultry and poultry-related products. The prevalence of Salmonella serovar Infantis has been increasing in poultry processing facilities over the past few years and in 2018 was identified as the causative agent for a large multistate outbreak linked to raw chicken. CRISPR-typing is a subtyping approach based on PCR and the sequencing of two Salmonella loci, CRISPR1 and CRISPR2. CRISPR-typing was used to interrogate 138 recent (2018-2019) isolates and genomes of ser. Infantis. Results show that the CRISPR elements are remarkably conserved in this serovar. The most conserved spacers, and those also unique to ser. Infantis, were used as targets to develop a ser. Infantis-specific qPCR assay. This assay was able to detect ser. Infantis in mixed serovar cultures of Salmonella, down to 0·1% of the population, highlighting the utility of this molecular approach in improving surveillance sensitivity for this important food safety pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY: The incidence of human salmonellosis cases caused by Salmonella enterica serovar Infantis (ser. Infantis) has been increasing, as has its prevalence in broiler chickens, which are a frequent reservoir of Salmonella. A cluster of ser. Infantis genetically linked to an outbreak strain have been identified in numerous processing facilities. A qPCR assay targeting CRISPR elements that are unique to ser. Infantis has been developed and can detect this serovar directly from mixed cultures. This assay is sensitive enough to reveal ser. Infantis within a mixed Salmonella population where it constitutes only 0·1% of the population. The rapid nature of qPCR lends this assay to high-throughput screening of poultry samples to detect this important pathogen.

Cross-protective Salmonella vaccine reduces cecal and splenic colonization of multidrug-resistant Salmonella enterica serovar Heidelberg

Salmonella vaccine strategies for food-producing animals have typically focused on a specific serovar that either causes production losses due to morbidity/mortality or is an important food safety pathogen for a particular food commodity. The Salmonella enterica serovar Typhimurium BBS 866 vaccine strain was designed to reduce serovar specificity to provide cross-protection against diverse Salmonella serovars, thereby broadening its applicability for multiple animal and poultry species. We reported cross-protection of the BBS 866 vaccine in swine [Vaccine 34:1241–6]. In the current study, we extend the efficacy of the Salmonella vaccine to a poultry commodity by revealing significant reduction of multidrug-resistant Salmonella enterica serovar Heidelberg colonization of the cecum and systemic dissemination to the spleen in BBS 866-vaccinated turkeys. Transcriptional analysis of whole blood from BBS 866-vaccinated turkeys revealed down-regulation of metabolic and immune genes (KCNAB1, ACOD1, GPR17, ADOR2AB, and IL-17RD), suggesting limited leukocyte activation without an overt peripheral inflammatory response to vaccination.

Escherichia coli O157:H7 and Salmonella Typhimurium adhesion to spinach leaf surfaces: Sensitivity to water chemistry and nutrient availability

This study investigated the effects of solution chemistry and growth conditions on bacterial deposition on spinach leaf surfaces using a parallel plate flow cell. Two food safety pathogens of concern and two non-pathogen bacterial surrogates (environmental E. coli isolates) were grown in ideal (LB media) and nutrient-restricted (M9 media) conditions. Bacterial attachment was quantified as mass transfer rate coefficients for cells suspended in 10 mM KCl, CaCl2 and artificial groundwater, and cell and leaf surfaces were extensively characterized (zeta potential, hydrophobicity, extracellular polymer (EPS) composition). Between the pathogens, E. coli O157:H7 attachment was greater than that of Salmonella Typhimurium, attributed to measurable variability in cell surface charge and hydrophobicity. When grown in M9 media, both pathogens were significantly more adhesive to spinach surfaces (p < 0.01) than when grown in LB media. Surrogates did not follow this trend and showed minimal changes in adhesion kinetics and surface properties between growth conditions. EPS sugar/protein ratios were reduced in some of the highest attachment scenarios, suggesting that changes in EPS composition in favor of proteins may play a role. These results show the importance of growth conditions and solution complexities in understanding mechanisms of aqueous bacterial adhesion to food surfaces.

Performance and carcass characteristics of commercial feedlot cattle from a study of vaccine and direct-fed microbial effects on Escherichia col O157:H7 fecal shedding.

The objective of this study was to quantify cattle performance and carcass characteristics associated with administration of a siderophore receptor and porin proteins-based vaccine (VAC) and a direct-fed microbial (DFM), which were originally evaluated for their impact on O157:H7 fecal shedding in a commercial feedlot population. Cattle (P = 17,148) were randomly allocated into 40 pens grouped by allocation dates into 10 complete blocks; pens within block were randomly allocated to control, VAC, DFM, or VAC + DFM treatment groups in a 2 × 2 factorial design. The DFM (Bovamine) was fed daily at the labeled dose of 10 cfu/animal of Lactobacillus acidophilus for the duration of the intervention period (mean = 86.6 d). The VAC cattle were vaccinated on Days 0 and 21 whereas unvaccinated cattle were not given a placebo or rehandled on Day 21. Data were analyzed using general and generalized linear mixed models that accounted for the study design. Main effects of DFM and VAC are reported as there were no significant treatment interactions for any of the outcomes evaluated. Vaccinated cattle had lower total weight gain (P < 0.01), ADG (P = 0.03), and cumulative DMI during the intervention period (P < 0.01) compared with unvaccinated cattle, whereas the DFM increased total weight gain (P = 0.03) and G:F (P = 0.05) during the intervention period. Daily DMI was decreased (P < 0.01) in vaccinated pens compared with unvaccinated pens during a 5-d period immediately following revaccination. After the intervention period was completed, cattle were sorted following the standard operating procedure for the feedlot and all cattle were fed the DFM from that point until harvest. Each steer was individually identified through harvest. At harvest, vaccinated cattle had more total days on feed (P < 0.01) with a larger HCW (P = 0.01) than nonvaccinated cattle, whereas cattle not fed the DFM during the intervention period had a significantly larger HCW (P < 0.01) than those fed the DFM during the intervention period. We conclude that the use of these DFM and vaccine products have differential and independent effects on cattle performance and carcass characteristics in a commercial feedlot setting. Although the magnitude of these effects may vary among production systems, a more comprehensive understanding of the potential production costs of preharvest food safety pathogen control programs is essential if such programs are to be fully adopted in the industry.

Modified Delphi Survey on Key Attributes for Selection of Water-treatment Technologies for Horticulture Irrigation

A wide range of water-treatment technologies is used to control waterborne microbial problems in greenhouse and nursery irrigation. An online modified Delphi survey was carried out to identify the perceived key attributes that growers should consider when selecting among water-treatment technologies and to characterize a list of 14 technologies based on those same attributes. The expert panel consisted of ornamental plant growers (n = 43), water-treatment industry suppliers (n = 28), and research and extension faculty (n = 34). The survey was delivered to the expert panel in two rounds. Response rate was 59% and 60% for the first and second rounds, respectively. Growers identified control of plant disease, algae, and biofilm as primary reasons for adopting technologies, whereas mandatory regulation was not a major reason for adoption. All 23 attributes (related to cost, system size, control of microorganisms, chemistry, ease of use, and regulation) were perceived to be important when selecting between water-treatment technologies. Injectable sanitizing chemicals such as chlorination were considered to have low capital cost, unlike technologies that required installation of more complex equipment, such as heat treatment, hydrogen peroxide, ozone, reverse osmosis, or ultraviolet radiation. Filtration (excluding membrane filtration) was the only technology not perceived to be effective to control microorganisms. Filtration and copper were not considered effective to control human food-safety pathogens. Ozone was rated the highest as a technology that removes or oxidizes agrochemicals. Chemical water treatments, as opposed to physical water treatments, were perceived to be sensitive to water quality parameters and to have residual effect through the irrigation. Chlorine gas was perceived to be the only technology for which regulatory permission would be an obstacle. All technologies were perceived to be effective in water with low electrical conductivity (EC) or in solutions containing water-soluble fertilizers. This survey documents perceived attributes of water-treatment technologies, which are most useful where experimental data are not yet available. Research and outreach needs were highlighted by cases where perceived attributes differed from available experimental data or where there was a lack of consensus between experts.

Investigation of Listeria, Salmonella, and toxigenic Escherichia coli in various pet foods.

The Veterinary Laboratory Investigation and Response Network (Vet-LIRN), in collaboration with the Food Emergency Response Network (FERN) and its Microbiology Cooperative Agreement Program (MCAP) laboratories, conducted a study to evaluate the prevalence of selected microbial organisms in various types of pet foods. The goal of this blinded study was to help the Center for Veterinary Medicine prioritize potential future pet food-testing efforts. The study also increased the FERN laboratories' screening capabilities for foodborne pathogens in animal feed matrices, since such pathogens may also be a significant health risk to consumers who come into contact with pet foods. Six U.S. Food and Drug Administration FERN MCAP laboratories analyzed approximately 1056 samples over 2 years. Laboratories tested for Salmonella, Listeria, Escherichia coli O157:H7 enterohemorrhagic E. coli, and Shiga toxin-producing strains of E. coli (STEC). Dry and semimoist dog and cat foods purchased from local stores were tested during Phase 1. Raw dog and cat foods, exotic animal feed, and jerky-type treats purchased through the Internet were tested in Phase 2. Of the 480 dry and semimoist samples, only 2 tested positive: 1 for Salmonella and 1 for Listeria greyii. However, of the 576 samples analyzed during Phase 2, 66 samples were positive for Listeria (32 of those were Listeria monocytogenes) and 15 samples positive for Salmonella. These pathogens were isolated from raw foods and jerky-type treats, not the exotic animal dry feeds. This study showed that raw pet foods may harbor food safety pathogens, such as Listeria monocytogenes and Salmonella. Consumers should handle these products carefully, being mindful of the potential risks to human and animal health.

Preharvest Food Safety: What Do the Past and the Present Tell Us About the Future?

ABSTRACT This paper summarizes the Pre-Harvest Food Safety Panel presentation at the Agricultural Safety and Health Council of America/National Institute for Occupational Safety and Health conference, “Be Safe, Be Profitable: Protecting Workers in Agriculture,” Dallas/Fort Worth, Texas, January 27–28, 2010. The ways we produce food and the ways consumers perceive agriculture have changed, bringing new challenges and new opportunities for human, animal, and environmental well-being. Issues that increasingly confront food producers today are about assuring the quality, safety, and security of the food products they produce. There are challenges and opportunities for protecting human health by controlling the presence of chemical, biological, and physical hazards in food. Today, demand for food products and the food producer's financial bottomline are affected by emerging preharvest acquired biological hazards such as bovine spongiform encephalopathy, antibiotic resistance, multidrug-resistant Salmonella, enterohemorrhagic Escherichia coli (EHEC; e.g. E. coli O157:H7), and other food safety pathogens. Years ago these issues were largely unheard of, but other zoonotic pathogens dominated the food safety landscape. Lessons of the past and examination of the present may provide insight into the future of food safety. There remains a need to fund food safety research that helps policy makers understand the marginal costs and benefits of science-based interventions at various levels of food production.

Occurrence ofSalmonella-Specific Bacteriophages in Swine Feces Collected from Commercial Farms

Salmonella is one of the leading causes of human foodborne illness and is associated with swine production. Bacteriophages are naturally occurring viruses that prey on bacteria and have been suggested as a potential intervention strategy to reduce Salmonella levels in food animals on the farm and in the lairage period. If phages are to be used to improve food safety, then we must understand the incidence and natural ecology of both phages and their hosts in the intestinal environment. This study investigates the incidence of phages that are active against Salmonella spp. in the feces of commercial finishing swine. Fecal samples (n = 60) were collected from each of 10 commercial swine finishing operations. Samples were collected from 10 randomly selected pens throughout each operation; a total of 600 fecal samples were collected. Salmonella spp. were found in 7.3% (44/600) of the fecal samples. Bacteriophages were isolated from fecal samples through two parallel methods: (1) initial enrichment in Salmonella Typhimurium; (2) initial enrichment in Escherichia coli B (an indicator strain), followed by direct spot testing against Salmonella Typhimurium. Bacteriophages active against Salmonella Typhimurium were isolated from 1% (6/600) of the individual fecal samples when initially enriched in Salmonella Typhimurium, but E. coli B-killing phages were isolated from 48.3% (290/600) of the fecal samples and only two of these phages infected Salmonella Typhimurium on secondary plating. Collectively, our results indicate that bacteriophages are widespread in commercial swine, but those capable of killing Salmonella Typhimurium may be present at relatively low population levels. These results indicate that phages (predator) populations may vary along with Salmonella (prey) populations; and that phages could potentially be used as a food safety pathogen reduction strategy in swine.

RAPID DETECTION OF BRUCELLA ABORTUS BY A NOVEL PROXIMITY LIGATION‐BASED LOOP‐MEDIATED ISOTHERMAL AMPLIFICATION METHOD

ABSTRACT Brucellosis is one of the most common zoonotic diseases, and current methods of detecting this pathogen are quite difficult. This work combines the benefits of a proximity ligation assay with those of a loop‐mediated isothermal amplification method to develop a novel proximity ligation‐based loop‐mediated isothermal amplification method useful for Brucella detection. The genomic DNA extraction procedure is not needed. Sensitivity of this assay for detecting Brucella abortus is 1 × 104 cells/mL in buffer and 1 × 105 cells/mL in milk. The time to detection is within 2 h of initiating the procedure, and no special equipment is needed. This new method is also suitable for the detection of other pathogens, and as such will be useful in the food safety industry.PRACTICAL APPLICATIONSPolymerase chain reaction (PCR) is a sensitivity method for microbe detection, but the complicated genomic DNA extraction procedure and costly equipment needed for this method makes the PCR method unpopular in developing countries. In this study, we present the novel proximity ligation‐based loop‐mediated isothermal amplification (P‐LAMP) method for Brucella detection; this is the first time to combine the monoclonal antibody for identify microbe and LAMP method for high performance amplification DNA. The genomic DNA extraction procedure is not needed and a water‐bath boiler is the only equipment required to complete the detection process. The P‐LAMP method is useful for food safety pathogen detection in developing countries.

Transcriptome Analysis of Organisms with Food Safety Relevance

Transcriptome analysis using microarrays has become a powerful tool to better understand the process of disease and other complex biological processes such as food spoilage and biofilm formation. This review is divided into two basic sections: 1) a short history and description of microarrays and 2) a discussion of studies involving bacterial food safety pathogens that focused on whole genome transcript analysis. Not included are the many studies using microarrays to identify, diagnose, or genetically characterize these organisms. This review focuses on studies involving Escherichia coli O157:H7, Salmonella spp., Campylobacter jejuni, Listeria monocytogenes, and Yersinia enterocolitica. Many of the studies involve altering the growth environment to simulate stress conditions and the use of host-pathogen model systems to explore virulence mechanisms. Few studies use conditions that might be considered unique to the food industry. Exceptions are studies of biofilm-specific transcriptome changes and analysis following pressure treatment. This review should not be considered as a comprehensive review, and where appropriate, species-specific reviews are cited that are more complete.

Effect of Different Cleaning Regimens on Recovery of Clostridium perfringens on Poultry Live Haul Containers

Clostridium perfringens is important to both poultry producers and humans. The excretion rate of pathogenic foodborne bacteria increases after live haul; however, the majority of research into flock cross-contamination has been performed on Salmonella and Campylobacter. Research into the sources of C. perfringens in poultry operations have implied that dirty transport containers do harbor this organism and, therefore, can potentially contaminate subsequent flocks. The objectives of this study were to examine both small plastic crates and large dump coops to determine which cleaning regimens were most effective in reducing C. perfringens contamination. Additionally, 2 different holding periods for small crates were compared to determine whether holding time influences C. perfringens recovery before and after cleaning. Two experiments were performed. One involved small plastic crates; the other involved large dump coops. Four small crate cleaning and disinfection treatments consisted of pressure washing, pressure washing and sun-drying, pressure washing with a (5%, vol/vol) sodium hypochlorite dip, and pressure washing with a quaternary ammonium dip. The second experiment involved dump coops. The 5 dump coop cleaning and disinfection treatments consisted of pressure washing, pressure washing with a (5%, vol/vol) sodium hypochlorite spray, pressure washing with a quaternary ammonium spray, 48-h drying after the sodium hypochlorite spray, and 48-h drying after the quaternary ammonium spray. The recovery of C. perfringens from small and large dirty transport containers averaged 1.94 and 4.43 log10 cfu/mL, respectively. There was no significant difference in C. perfringens recovery based on holding time for small crates. With small crates, pressure washing provided a significant decrease in the amount of C. perfringens recovered. The greatest bacterial reduction in dump coops, 2 to 3 log10 cfu/mL, was observed after 48 h of drying. This information provides solutions to poultry operations to reduce the cross-contamination of this food safety pathogen via transport containers.

Behavior of cattle towards devices to detect food-safety pathogens in feedlot pens

Our objective was to optimize a protocol using rope devices designed to detect Escherichia coli O157:H7 in feedlot pens by (1) determining if the number of devices influenced the percent of cattle sampled, (2) describing when the cattle contacted the devices, and (3) determining if the time of removal or number of devices influenced the recovery or E. coli O157:H7. Overall, 2948 cattle were observed in 24 commercial feedlot pens, eight pens each in the autumn, winter and summer. Three or seven devices per pen were placed near the water tank and over the feed bunk approximately one hour prior to sunset. Cattle were observed for a 2-hour period to measure (1) the duration of time until they made contact with the devices, and (2) the type of contact they had with the devices. One tail from each of the devices was collected at the end of the 2-hour observation period (ending approximately one hour after sundown) and the other tail was collected the next morning to test for the presence of E. coli O157:H7. Recovery of E. coli O157:H7 was not significantly different using three or seven devices (p&gt;0.10), or if devices were left available overnight (p&gt;0.10). The rate of first contacts did not differ between pens with three or seven devices in any of the 30-minute periods of observation (p&gt;0.50). However, regardless of the number of devices in the pen, the first contact rate was highest in the first 30 minutes and decreased significantly with time (p&lt;0.001). Over the 2-hour observation period, a greater percentage of cattle in pens with seven devices had physical (p&lt;0.01), brief oral (p&lt;0.02), or prolonged oral contact (p&lt;0.01) than cattle in pens with three devices. Therefore, to maximize the number of cattle sampled per pen, the number of devices and length of time the devices are available were important factors of the sampling strategy.

Identification and Classification of Consumer Food-Handling Behaviors for Food Safety Education

Objective To identify key behaviors associated with major food safety pathogen control factors. Design World Wide Web-based descriptive study with 4 tasks: compile a list of food-handling behaviors from the literature; use Delphi process to build consensus, rank order, and edit lists of behaviors; assess content and construct validity; and review results of Delphi process at a summit meeting of selected experts to make final recommendations for a food safety behavior list. Subjects/setting A convenience sample of 10 epidemiologists, 11 food microbiologists, 10 food safety educators, and 10 food safety policy makers was recruited from lists of nationally known experts. Twenty-four experts completed 4 rounds of surveys presented to them via a Web site. Six experts attended a face-to-face meeting to finalize behavior lists. Statistical analyses performed Descriptive statistics and sum of observation data were used to determine rank order and validity. Results Twenty-nine key food-handling behaviors for maintaining the safety of food and reducing the number of cases and outbreaks of foodborne illness were identified. These were rank-ordered within 5 pathogen control factors: practice personal hygiene, cook foods adequately, avoid cross-contamination, keep foods at safe temperatures, and avoid foods from unsafe sources. Applications/conclusions This list of rank-ordered behaviors grouped by pathogen control factor should help dietitians and educators confidently teach food safety guidance that will be most effective in preventing illness. J Am Diet Assoc. 2001;101:1326-1332, 1337-1339.

Farm and management variables linked to fecal shedding of Campylobacter and Salmonella in commercial squab production

A cross-sectional study was performed to determine the relationship of farm variables and management practices to fecal shedding of Campylobacter or Salmonella on commercial squab (young pigeon) farms. A detailed survey provided information on biosecurity, cleaning and disinfection, bird health, vector control, and loft and pen. Twenty pigeons on each of 12 farms were cultured before and after the producers completed a voluntary quality assurance training program (QAP), based on principles of hazard analysis critical control point (HACCP). The prevalence of positive samples for Salmonella and C. jejuni was 1/480 (0.21%) and 19/480 (3.96%), respectively. Campylobacter was present on one farm during both visits; three farms during the first visit, and three farms during the second visit. Analysis by fixed-effects logistic regression showed the probability of having a positive C. jejuni culture was increased by not using dry manure in the nesting material, not cleaning shipping crates, cleaning landing boards, and by increased frequency of chemical disinfection of water. Having a positive parent and higher numbers of squab per pen (density) were also associated with higher odds of being positive for C. jejuni. Factors not associated with a positive C. jejuni culture included, other avian species on the farm, type of shipping crate, covered drinkers, fly problems, bird age, level of nest box within the loft, and QAP training. Prevalence of food safety pathogens was extremely low on the squab facilities tested as compared with reports from commercial broiler or turkey flocks. This observation suggests that one or more farm variables or management practices were effectively reducing infection, or possibly a species-related difference existed in carriage rates and shedding of pathogens. These results emphasize critical control points for food safety pathogens may vary widely, and the formulation of effective QAP programs are dependent on science-based knowledge of diverse animal production systems.

Developing and distributing user-friendly application software

The adoption of new techniques in predictive microbiology by the food industry will ultimately be dependent on the development of user-friendly application software that makes it easy for non-research personnel to employ the mathematical models. Such applications should be an integral part of projects in predictive microbiology. Recommendations related to the architecture, speed, protection, testing, and distribution of application software are presented based on our experience in developing and distributing the ‘Microbial Food Safety Pathogen Modeling Program’.