Comparison of Three Preharvest Sampling Strategies to Monitor Pathogens in Cattle Lairage Areas.

The objective of this study was to compare preharvest monitoring strategies by evaluating three different sampling methods in the lairage area to determine pathogen recovery for each sampling method and incoming pathogen prevalence from the cattle to inform in-plant decision making. Samples were gathered over a 5-month period, from February to June 2022, at a harvesting and processing facility located in Eastern Nebraska. Sampling methods included (i) fecal pats, (ii) boot swabs, and (iii) MicroTally swab. A total of 329 samples were collected over the study period (fecal pats: n = 105, boot swabs: n = 104, and MicroTally swabs: n = 120). Specific media combinations, an incubation temperature of 42°C, and incubation timepoints (18-24 h) were utilized for each matrix and the prevalence of Salmonella, Escherichia coli O157:H7, and six non-O157 Shiga-toxin producing E. coli (STEC) was evaluated using the BAX system Real-Time PCR assay. Overall, results from the study concluded that boot swabs were an effective sampling method for pathogen detection in the cattle lairage area. Boot swabs (97.1%) were statistically more likely to detect for Salmonella (p < 0.05) when compared to fecal pats (67.6%) and MicroTally swab (77.5%) methods. For E. coli O157:H7 and STEC - O26, O121, O45, and O103 prevalence, boot swabs were significantly better at detecting for these pathogens (p < 0.05) than MicroTally swabs (OR = 3.16 - 11.95) and a comparable sampling method to fecal pats (OR = 0.93 - 2.01, p > 0.05). Lastly, all three sampling methods detected a very low prevalence for E. coli O111 and O145; therefore, no further analysis was conducted. The boot swab sampling method was strongly favored because they require little training to implement, are inexpensive, and they do not require much sampling labor; therefore, would be a simple and effective sampling method to implement within the industry to evaluate pathogen prevalence preharvest.

Mitigation of Salmonella in Ground Pork Products through Gland Removal in Pork Trimmings.

Bio-mapping studies conducted in pork harvest and fabrication facilities have indicated that Salmonella is prevalent and mitigations are needed to reduce the pathogen in trim and ground products. Salmonella can be isolated from the lymph nodes and can cause contamination in comminuted pork products. The objective of this study was to determine if physically removing topical and internal lymph nodes in pork products prior to grinding would result in the mitigation of Salmonella and a reduction in indicators in the final ground/comminuted products. In total, three treatment groups were assigned in a commercial pork processing facility as follows: (1) untreated control, (2) topical (surface) glands removed before grinding, and (3) topical, jowl, and internal lymph nodes and glands removed before grinding. Indicator microorganisms were determined using the BioMérieux TEMPO® system and the quantification of Salmonella was performed using the BAX® System Real-Time Salmonella SalQuant® methodology. The removal of lymph nodes located on the topical and internal surfaces and in the jowl significantly (p < 0.05) reduced the presence of Salmonella and also reduced the presence of indicator organisms according to this study. Briefly, 2.5-Log CFU/sample of Salmonella was initially observed in the trim samples, and the ground samples contained 3.8-Log CFU/sample of Salmonella. The total numbers were reduced to less than 1-Log CFU/sample in both trim and ground products. This study indicates a need for lymph node mitigation strategies beginning prior to harvest, in order to prevent contamination in further-processed pork products.

Prevalence of Foodborne Pathogens in Pacific Northwest Beef Feedlot Cattle Fed Two Different Direct-Fed Microbials.

In recent years, there has been an increased interest in beef cattle shedding of foodborne pathogens due to the potential to contaminate surrounding food crops; however, the number of studies published on this topic has declined as the majority of research has emphasized on postharvest mitigation efforts. A field study was conducted to determine the prevalence of pathogens and indicator bacteria in beef cattle fed two different direct-fed microbials (DFMs). Fecal samples from a total of 3,708 crossbred yearling cattle randomly assigned to 16 pens and two treatment groups at a commercial cattle feedlot were taken. During the study period, diets were supplemented with two different DFMs i.) Lactobacillus acidophilus (NP51) and Propionibacterium freudenreichii (NP24) (9 log10CFU/head/day), and ii.) Lactobacillus salivarius (L28) (6 log10CFU/head/day). Fecal samples from pen floors were collected on days 0, 21, 42, 63, 103, and analyzed for the presence of Salmonella and E. coli O157:H7 and concentration of E. coli O157:H7, Enterobacteriaceae, and C. perfringens. Fecal samples collected from cattle fed L28 had significantly lower concentration of C. perfringens (p < 0.05) and had a similar prevalence with no significant differences in E. coli O157:H7 as those fed NP51/NP24 through the study until day 103. On day 103, the prevalence in cattle fed L28 was 40% with a concentration of 0.95 log10MPN/g while those fed NP51/NP24 were 65% with a concentration of 1.2 log10MPN/g. Cattle supplemented with NP51/NP24 achieved a significant log reduction of EB by 2.4 log10CFU/g over the course of the 103-day supplementation period compared to L28. Salmonella prevalence was also measured, but not detected in any samples at significant amounts to draw conclusions. It is evident that E. coli O157:H7 and other foodborne pathogens are still prevalent in cattle operations and that preharvest mitigation strategies should be considered to reduce the risk to beef products.

Understanding potential cattle contribution to leafy green outbreaks: A scoping review of the literature and public health reports.

Recently, multiple reports from regulatory agencies have linked leafy green outbreaks to nearby or adjacent cattle operations. While they have made logical explanations for this phenomenon, the reports and data should be summarized to determine if the association was based on empirical data, epidemiological association, or speculation. Therefore, this scoping review aims to gather data on the mechanisms of transmission for pathogens from livestock to produce, identify if direct evidence linking the two entities exists, and identify any knowledge gaps in the scientific literature and public health reports. Eight databases were searched systematically and 27 eligible primary research products, which focus on produce safety concerning proximity to livestock, provided empirical or epidemiological association and described mechanisms of transmission, qualitatively or quantitatively were retained. Fifteen public health reports were also covered. Results from the scientific articles provided evidence that proximity to livestock might be a risk factor; however, most lack quantitative data on the relative contribution of different pathways for contamination. Public health reports mainly indicate livestock presence as a possible source and encourage further research. Although the collected information regarding the proximity of cattle is a concern, data gaps indicate that more studies should be conducted to determine the relative contribution of different mechanisms of contamination and generate quantitative data to inform food safety risk analyses, regarding leafy greens produced nearby livestock areas.

Rapid Quantitative Method Development for Beef and Pork Lymph Nodes Using BAX® System Real Time Salmonella Assay.

The goal of this study was to develop a rapid RT-PCR enumeration method for Salmonella in pork and beef lymph nodes (LNs) utilizing BAX®-System-SalQuant® as well as to assess the performance of the methodology in comparison with existing ones. For study one: PCR curve development, pork, and beef LNs (n = 64) were trimmed, sterilized, pulverized, spiked with 0.00 to 5.00 Log CFU/LN using Salmonella Typhimurium, and then homogenized with BAX-MP media. Samples were incubated at 42 °C and tested at several time points using the BAX®-System-RT-PCR Assay for Salmonella. Cycle-Threshold values from the BAX®-System, for each Salmonella concentration were recorded and utilized for statistical analysis. For study two: Method comparison; additional pork and beef LNs (n = 52) were spiked and enumerated by (1) 3M™EB-Petrifilm™ + XLD-replica plate, (2) BAX®-System-SalQuant®, and (3) MPN. Linear-fit equations for LNs were estimated with recovery times of 6 h and a limit of quantification (LOQ) of 10 CFU/LN. Slopes and intercepts for LNs using BAX®-System-SalQuant® when compared with MPN were not significantly different (p < 0.05), while the same parameters for 3M™EB-Petrifilm™ + XLD-replica plate were significantly different (p > 0.05). The results support the capability of BAX®-System-SalQuant® to enumerate Salmonella in pork and beef LNs. This development adds support to the use of PCR-based quantification methodologies for pathogen loads in meat products.

Validation of a Bacteriophage Hide Application to Reduce STEC in the Lairage Area of Commercial Beef Cattle Operations.

Finalyse, a T4 bacteriophage, is a pre-harvest intervention that utilizes a combination of bacteriophages to reduce incoming Escherichia coli O157:H7 prevalence by destroying the bacteria on the hides of harvest-ready cattle entering commercial abattoirs. The objective of this study was to evaluate the efficacy of Finalyse, as a pre-harvest intervention, on the reduction in pathogens, specifically E. coli O157:H7, on the cattle hides and lairage environment to overall reduce incoming pathogen loads. Over 5 sampling events, a total of 300 composite hide samples were taken using 25 mL pre-hydrated Buffered Peptone Water (BPW) swabs, collected before and after the hide wash intervention, throughout the beginning, middle, and end of the production day (n = 10 swabs/sampling point/timepoint). A total of 171 boot swab samples were also simultaneously taken at the end of the production day by walking from the front to the back of the pen in a pre-determined 'Z' pattern to monitor the pen floor environment from 3 different locations in the lairage area. The prevalence of pathogens was analyzed using the BAX® System Real-Time PCR Assay. There were no significant reductions observed for Salmonella and/or any Shiga toxin-producing E. coli (STEC) on the hides after the bacteriophage application (p > 0.05). Escherichia coli O157:H7 and O111 hide prevalence was very low throughout the study; therefore, no further analysis was conducted. However, boot swab monitoring showed a significant reduction in E. coli O157:H7, O26, and O45 in the pen floor environment (p < 0.05). While using Finalyse as a pre-harvest intervention in the lairage areas of commercial beef processing facilities, this bacteriophage failed to reduce E. coli O157:H7 on the hides of beef cattle, as prevalence was low; however, some STECs were reduced in the lairage environment, where the bacteriophage was applied. Overall, an absolute conclusion was not formed on the effectiveness of Finalyse and its ability to reduce E. coli O157:H7 on the hides of beef cattle, as prevalence on the hides was low.

Reduction of Pathogens in Feces and Lymph Nodes Collected from Beef Cattle Fed Lactobacillus salivarius (L28), Lactobacillus acidophilus (NP51) and Propionibacterium freudenreichii (NP28), Commercially Available Direct-Fed Microbials.

The purpose of the study was to evaluate the prevalence and concentration of foodborne pathogens in the feces and peripheral lymph nodes (PLNs) of beef cattle when supplemented with direct-fed microbials (DFMs) in feedlots. Fecal samples were collected from the pen floors over a 5-month period at three different feedlots in a similar geographical location in Nebraska, where each feed yard represented a treatment group: (i.) control: no supplement, (ii.) Bovamine Defend: supplemented with NP51 and NP24 at a target dose of 9 log10CFU/g/head/day, and (iii.) Probicon: supplemented with L28 at a target dose of 6 log10CFU/g/head/day. Each fecal sample was tested for the prevalence of E. coli O157:H7 and Salmonella, and concentration of E. coli O157:H7, Enterobacteriaceae and Clostridium perfringens. Cattle were harvested and PLNs were collected on the harvest floor. Real-time Salmonella PCR assays were performed for each PLN sample to determine Salmonella presence. The cattle supplemented with both DFMs had reduced foodborne pathogens in fecal samples, but feces collected from the pens housing the cattle supplemented with Probicon consistently had significantly less E. coli O157:H7 and Salmonella prevalence as well as a lower C. perfringens concentration. While DFMs do not eliminate foodborne pathogens in fecal shedding and PLNs, the use of DFMs as a pre-harvest intervention allows for an effective way to target multiple pathogens reducing the public health risks and environmental dissemination from cattle.

Quantitative Bio-Mapping of Salmonella and Indicator Organisms at Different Stages in a Commercial Pork Processing Facility.

The purpose of this study was to develop a quantitative baseline of indicator organisms and Salmonella by bio-mapping throughout the processing chain from harvest to final product stages within a commercial conventional design pork processing establishment. Swab samples were taken on the harvest floor at different processing steps, gambrel table, after polisher, before final rinse, after the final rinse, post snap chill, and after peroxyacetic acid (PAA) application, while 2-pound product samples were collected for trim and ground samples. The samples were subjected to analysis for indicator microorganism enumeration, Aerobic Count (AC), Enterobacteriaceae (EB), and generic Escherichia coli (EC), with the BioMérieux TEMPO®. Salmonella prevalence and enumeration was evaluated using the BAX® System Real-Time Salmonella and the SalQuant™ methodology. Microbial counts were converted to Log Colony-forming units (CFU) on a per mL, per g or per sample basis, presented as LogCFU/mL, LogCFU/g and LogCFU/sample, prior to statistical analysis. All indicator microorganisms were significantly reduced at the harvest floor (p-value < 0.001), from gambrel table to after PAA cabinet location. The reduction at harvest was 2.27, 2.46 and 2.24 LogCFU/mL for AC, EB and EC, respectively. Trim sample values fluctuated based on cut, with the highest average AC count found at neck trim (2.83 LogCFU/g). Further process samples showed the highest AC count in sausage with a mean of 5.28 LogCFU/g. EB counts in sausage (3.19 LogCFU/g) showed an evident increase, compared to the reduction observed at the end of harvest and throughout trim processing. EC counts showed a similar trend to EB counts with the highest value found in sausage links (1.60 LogCFU/g). Statistical microbial process control (SPC) parameters were also developed for each of the indicator microorganisms, using the overall mean count (X=), the Lower control limit (LCL) and Upper control limit (UCL) at each sampling location. For Salmonella prevalence, a total of 125/650 samples were found positive (19%). From those positive samples, 47 samples (38%) were suitable for enumeration using the BAX® System SalQuant™, the majority detected at the gambrel table location. From those enumerable samples, 60% were estimated to be between 0.97 and 1.97 LogCFU/sample, while the rest (40%) were higher within the 2.00−4.02 LogCFU/sample range. This study provides evidence for the application of indicator and pathogen quantification methodologies for food safety management in commercial pork processing operations.

Sodium benzoate and sodium bisulfate as preservatives in apple juice and alternative sanitizers for washing cherry tomatoes.

Unpasteurized apple ciders and fresh produce have been linked to multistate outbreaks due to contamination by foodborne pathogens. Organic acids such as benzoic acid are effective antimicrobials, and acidified sodium benzoate (NaB) has been reported to be effective in reducing pathogens inoculated on cherry tomatoes and preventing cross-contamination. Sodium bisulfate (SBS) is a powerful acidulant but has not been studied in combination with NaB. The objective of the present study was to characterize the antibacterial activity of SBS and its combination with NaB in tryptic soy broth (TSB) and apple juice, as well as washing cherry tomatoes. The minimum inhibitory concentration and minimum bactericidal concentration of SBS were all 0.5% w/v (corresponding to TSB medium pH of 4.30) and 1.0% w/v (corresponding to TSB medium pH of 2.88), respectively, for Escherichia coli O157:H7 ATCC 43895, Salmonella Enteritidis ATCC 13076, and Listeria monocytogenes Scott A. In TSB, the triple combination of 1.0% w/v SBS, 0.1% w/v NaB, and 0.02% w/v oregano oil (OO) showed the faster inactivation rate of the three bacteria than treatments with one or two antimicrobials; the activity of double combinations followed the order of 0.1% w/v NaB +1.0% w/v SBS > 0.1% w/v NaB +0.5% w/v SBS + 0.02% w/v OO > 0.1% w/v NaB +0.5% w/v SBS. pH was a critical factor in the activity of antimicrobial combinations in TSB, and L. monocytogenes was more resistant than Gram-negative E. coli O157:H7 and S. Enteritis. In apple juice added with 0.05% w/v NaB, 0.25% w/v SBS, and 0.01% w/v OO alone or in combinations, 5 log CFU/mL or greater reductions in 72 h were observed for E. coli O157:H7 and S. Enteritidis in double and triple combinations, while only the triple combination and the SBS-OO combination resulted in the same effect for L. monocytogenes. For cherry tomatoes inoculated with 6.8 log CFU/g E. coli O157:H7, complete decontamination (>6 log CFU/g) was achieved after soaking for 1 min in solutions containing 0.5-1.5% w/v SBS and 0.1% w/v NaB or 1.5% w/v SBS alone, and no pathogens were detected in all wash solutions containing 0.5-1.5% w/v SBS with and without NaB. The lower pH of wash solutions with a higher amount of SBS was a dominant factor in decontamination and prevention of cross-contamination. The present study showed the potential of SBS and its combination with NaB to enhance the safety of apple juice and cherry tomatoes.

Bio-Mapping of Microbial Indicators to Establish Statistical Process Control Parameters in a Commercial Beef Processing Facility.

The objective was to conduct a bio-mapping of microbial indicators to determine statistical process control (SPC) parameters at a beef processing plant to establish microbiological baselines and process control parameters to support food safety management decisions. EZ-ReachTM swabs were used to collect 100 cm2 area samples at seven different locations throughout the beef processing line at four different regions on the carcass. Each of the eight sampling days evaluated included three samples collected per sampling location/carcass region for a total of 84 samples per day. Enumeration of total aerobic bacteria, Enterobacteriaceae, and Escherichia coli was performed on each sample. Microbial SPC parameters were estimated for each sampling point. Statistical differences between sampling points for all carcass locations (p < 0.001) followed an overall trend with higher values at pre- and post-evisceration with a continuous decrease until final interventions with a slight increase in counts during the chilling process and a final increase after fabrication. Variability at sampling points is the result of the nature of the process and highlights open opportunities for improvement of the food safety system. Microbial baselines and SPC parameters will help support decision making for continuous process improvement, validation of intervention schemes, and corrective action implementation for food safety management.

The Effects of Castration, Implant Protocol, and Supplementation of Bos indicus-Influenced Beef Cattle under Tropical Savanna Conditions on Growth Performance, Carcass Characteristics, and Meat Quality.

The effects of castration, supplementation, and implant protocol (IP) on growth, carcass characteristics, and meat quality of grass-fed cattle were evaluated. Two experiments followed a two-way ANOVA and a 2 × 2 factorial arrangement. Experiment-I, 99 bulls were evaluated for: (a) supplementation (mineral (MS) or strategic protein-energy supplementation (SS), and (b) IP (repeated (day-0 and day-90) Zeranol-72 mg implantation (Zeranol-Zeranol) or Trenbolone Acetate-140 mg/Estradiol-20 mg (day-0) followed by Zeranol-72 mg (day-90) (TBA/E2-Zeranol). Experiment II, 50 animals were evaluated for: (a) IP (like Experiment-I), and (b) male class (steers vs. bulls). In Experiment-I, SS bulls had greater growth rate, carcass yield, and yield of high-valued boneless lean cuts than MS bulls, while decreasing (p < 0.05) time to harvest. Steaks from SS-bulls on TBA/E2-Zeranol IP were more (p = 0.05) tender than SS/Zeranol-Zeranol counterparts. Experiment-II bulls had greater growth than steers, but decreased (p < 0.05) carcass quality aspects. Zeranol-Zeranol increased (p < 0.01) meat tenderness of steers. Interactions (p < 0.05) affected cutability (Experiment-II) and meat sensory traits (Experiment-I/II). The SS improved growth, carcass yield, and shortened days until harvest of bulls, while TBA/E2-Zeranol IP positively affected tenderness in bull meat only. Castration improved carcass quality while the implant effects on cutability and tenderness were male-class dependent.

Effects of Sex Class, a Combined Androgen and Estrogen Implant, and Pasture Supplementation on Growth and Carcass Performance and Meat Quality of Zebu-Type Grass-Fed Cattle.

Forty-seven Zebu calves were used to determine the effects of class (bull or steer), supplementation (SUPPL, a poultry litter-based supplement or mineral supplementation), and implant (20 mg estradiol combined with 120 mg of trenbolone acetate or no implant) on growth and carcass performance and beef eating quality. The average daily gain (ADG) of implanted cattle significantly increased for steers, but not for bulls. The SUPPL treatment increased ADG by 8.63% from day 0 to end, and shortened in 73.3 d the time to reach 480 kg BW (p < 0.01). Compared to bulls, the steer carcasses exhibited more desirable maturity and finish scores, thicker back fat (p < 0.05), and yielded greater (p < 0.01) percentages of high-value boneless subprimals (HVBLS) (+1.64%) and total cuts (1.35%). The SUPPL bulls dressed 2.63 and 1.63% greater than non-supplemented bulls and SUPPL steers, respectively (p < 0.05). Meat sensory quality was subtly affected (p < 0.05) by sex class or supplementation. The implant did not affect (p > 0.05) shear force or sensory ratings. The supplementation improved key growth performance traits while it adversely affected tenderness-related sensory traits. The implant enhanced the rate of gain of steers only, without improving cut-out yields or inducing adverse effects on palatability traits in both steers and bulls.

In-Plant Intervention Validation of a Novel Ozone Generation Technology (Bio-Safe) Compared to Lactic Acid in Variety Meats.

The objective of this experiment was to compare the antimicrobial efficacy of an aqueous ozone intervention and a lactic acid solution on natural microbiota of variety meats in a commercial beef processing plant. EZ-Reach™ swabs were used to collect 100 cm2 area samples before and after ozone and lactic acid intervention application for three different offals (head, heart, and liver). Each repetition included 54 samples per variety meat and antimicrobial for a total of 162 samples per repetition. Enumeration of total aerobic bacteria (APC) and Escherichia coli (EC) was performed on each sample. Microbial counts for both microorganisms evaluated were significantly reduced (p < 0.001) after lactic acid immersion (2-5%) and ozone intervention for all variety meats, with the exception of ozone intervention in EC counts of the heart samples. APC after lactic acid intervention was reduced on average by 1.73, 1.66, and 1.50 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 1.66, 0.52, and 1.20 Log CFU/sample. EC counts after lactic acid intervention were reduced on average by 0.96, 0.79, and 1.00 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 0.75, 0.62, and 1.25 Log CFU/sample. The aqueous ozone antimicrobial scheme proved to be a promising intervention for the in-plant reduction of indicator levels in variety meats, specifically heads, hearts, and livers.

Biomapping of Microbial Indicators on Beef Subprimals Subjected to Spray or Dry Chilling over Prolonged Refrigerated Storage.

As the global meat market moves to never frozen alternatives, meat processors seek opportunities for increasing the shelf life of fresh meats by combinations of proper cold chain management, barrier technologies, and antimicrobial interventions. The objective of this study was to determine the impact of spray and dry chilling combined with hot water carcass treatments on the levels of microbial indicator organisms during the long-term refrigerated storage of beef cuts. Samples were taken using EZ-Reach™ sponge samplers with 25 mL buffered peptone water over a 100 cm2 area of the striploin. Sample collection was conducted before the hot carcass wash, after wash, and after the 24 h carcass chilling. Chilled striploins were cut into four sections, individually vacuum packaged, and stored to be sampled at 0, 45, 70, and 135 days (n = 200) of refrigerated storage and distribution. Aerobic plate counts, enterobacteria, Escherichia coli, coliforms, and psychrotroph counts were evaluated for each sample. Not enough evidence (p > 0.05) was found indicating the hot water wash intervention reduced bacterial concentration on the carcass surface. E. coli was below detection limits (<0.25 CFU/cm2) in most of the samples taken. No significant difference (p > 0.05) was found between coliform counts throughout the sampling dates. Feed type did not seem to influence the (p > 0.25) microbial load of the treatments. Even though no immediate effect was seen when comparing spray or dry chilling of the samples at day 0, as the product aged, a significantly lower (p < 0.05) concentration of aerobic and psychrotrophic organisms in dry-chilled samples could be observed when compared to their spray-chilled counterparts. Data collected can be used to select alternative chilling systems to maximize shelf life in vacuum packaged beef kept over prolonged storage periods.

In-Plant Validation of Novel On-Site Ozone Generation Technology (Bio-Safe) Compared to Lactic Acid Beef Carcasses and Trim Using Natural Microbiota and Salmonella and E. coli O157:H7 Surrogate Enumeration.

The purpose of this study was to evaluate the antimicrobial efficacy of an aqueous ozone (Bio-Safe) treatment and lactic acid solutions on natural microbiota and E. coli O157:H7 and Salmonella surrogates on beef carcasses and trim in a commercial beef processing plant. For every repetition, 40 carcass and 40 trim swabs (500 cm2) were collected. Samples were taken using EZ-ReachTM swabs, and plated into aerobic plate count (APC), coliform, and E. coli PetrifilmTM for enumeration. In addition, a five-strain cocktail (MP-26) of E. coli surrogates was inoculated onto trim. For every trim surrogate repetition, 30 trim pieces were sampled after attachment and after ozone intervention. Samples were diluted and counts were determined using the TEMPO® system for E. coli enumeration. Ozone and lactic acid interventions significantly reduced (p < 0.003) bacterial counts in carcasses and trim samples. Moreover, lactic acid further reduced APC and coliforms in trim samples compared to ozone intervention (p < 0.009). In the surrogate trials, ozone significantly reduced (p < 0.001) surrogate concentration. Historical data from the plant revealed a reduction (p < 0.001) of presumptive E. coli O157:H7 in trim after a full year of ozone intervention implementation. The novel technology for ozone generation and application as an antimicrobial can become an alternative option that may also act synergistically with existing interventions, minimizing the risk of pathogens such as Salmonella and E. coli O157:H7.

Genotypic Characterization of Antimicrobial Resistant Salmonella spp. Strains from Three Poultry Processing Plants in Colombia.

The poultry industry in Colombia has implemented several changes and measures in chicken processing to improve sanitary operations and control pathogens' prevalence. However, there is no official in-plant microbial profile reference data currently available throughout the processing value chains. Hence, this research aimed to study the microbial profiles and the antimicrobial resistance of Salmonella isolates in three plants. In total, 300 samples were collected in seven processing sites. Prevalence of Salmonella spp. and levels of Enterobacteriaceae were assessed. Additionally, whole-genome sequencing was conducted to characterize the isolated strains genotypically. Overall, the prevalence of Salmonella spp. in each establishment was 77%, 58% and 80% for plant A, B, and C. The mean levels of Enterobacteriaceae in the chicken rinsates were 5.03, 5.74, and 6.41 log CFU/mL for plant A, B, and C. Significant reductions were identified in the counts of post-chilling rinsate samples; however, increased levels were found in chicken parts. There were six distinct Salmonella spp. clusters with the predominant sequence types ST32 and ST28. The serotypes Infantis (54%) and Paratyphi B (25%) were the most commonly identified within the processing plants with a high abundance of antimicrobial resistance genes.

Multiple Interventions for Improving Food Safety Practices in 2 Small Beef Abattoirs of Honduras and Associated Impacts on Risk-Mitigation Management.

Mitigation of risk for Shiga toxin-producing Escherichia coli (STEC) and Salmonella contamination was evaluated after a multiple-intervention approach (comprising food safety education and training, implementation of customized food safety practices and programs, and environmental monitoring programs with audits and corrective actions) in 2 small Honduran beef abattoirs. Previously, neither abattoir had food safety programs in place nor were they subjected to strict food safety regulatory surveillance. Abattoirs A and B were sampled on 4 nonconsecutive months each. Swab samples of abattoir A (n = 160, 40 samples per sampling date) and abattoir B (n = 78, 16-22 samples per sampling date) were taken from direct and indirect food contact surfaces, screened by BAX real-time polymerase chain reaction (PCR) assays and confirmed using immunomagnetic separation, selective media, and latex agglutination. In abattoir A, Salmonella presence was negligible, whereas presumptive STECs were present in 10%, 12.5%, 0%, and 5% of the environmental samples respective to each sampling month, indicating a reduction of STEC (P = .06) by the third and fourth sampling months. Conversely, presumptive STEC presence was negligible in abattoir B, whereas Salmonella presence for each sampling month was of 5.6%, 6.3%, 27.3%, and 0.0%, respectively. Upon the increased pathogen presence detected on the third sampling month, additional actions were taken to reinforce the implementation of food safety practices and programs, which resulted in a Salmonella reduction to 0% by the fourth sampling month (P = .013). The satisfactory results strongly suggest that a multiple-intervention approach is crucial to improve food safety in this type of premises.

Phenotypic and Genotypic Characterization of Antimicrobial Resistance in Salmonella Strains Isolated from Chicken Carcasses and Parts Collected at Different Stages during Processing.

Chicken carcass and parts rinsate samples and fecal samples were collected at different stages in a commercial poultry processing facility. Microbiological analysis was conducted to determine the levels of multiple indicator microorganisms and prevalence of Salmonella. Antibiotic susceptibility testing was conducted on Salmonella isolates to determine antimicrobial resistance profiles. Whole genome sequencing was performed for tracing isolates in the processing chain, serotyping, and determining genetic features associated with virulence and antimicrobial resistance in the bacterial genome. The overall contamination rate was 55% for Salmonella. Prevalence increased by 80% in chicken parts compared with the previous processing site (postchill carcasses), suggesting possible cross-contamination during the cutting and deboning processes. The levels of indicator organisms were reduced significantly from the prescalding to the parts processing sites, by 3.22 log CFU/mL for aerobic plate count, 3.92 log CFU/mL for E. coli, 3.70 log CFU/mL for coliforms, and 3.40 log CFU/mL for Enterobacteriaceae. The most frequent resistance in Salmonella was associated with tetracycline (49 of 50, 98%) and streptomycin (43 of 50, 86%). Some Salmonella isolates featured resistance to the cephems class of antibiotics (up to 15%). Whole genome sequencing analysis of Salmonella isolates identified nine different clonal populations distributed throughout the samples taken at different stages; serotype Kentucky was the most commonly isolated. This study provides insights into microbial profiling and antibiotic-resistant strains of chicken rinsate samples during poultry processing.

A Systematic Approach to Identify and Characterize the Effectiveness and Safety of Novel Probiotic Strains to Control Foodborne Pathogens.

A total of 44 lactic acid bacteria (LAB) strains originally isolated from cattle feces and different food sources were screened for their potential probiotic features. The antimicrobial activity of all isolates was tested by well-diffusion assay and competitive exclusion on broth against Salmonella Montevideo, Escherichia coli O157:H7 and Listeria monocytogenes strain N1-002. Thirty-eight LAB strains showed antagonistic effect against at least one of the pathogens tested in this study. Improved inhibitory effect was observed against L. monocytogenes with zones of inhibition up to 24 mm when LAB overnight cultures were used, and up to 21 mm when cell-free filtrates were used. For E. coli O157:H7 and Salmonella maximum inhibitions of 12 and 11.5 mm were observed, respectively. On broth, 43 strains reduced L. monocytogenes up to 9.06 log10 CFU/ml, 41 reduced E. coli O157:H7 up to 0.84 log10 CFU/ml, and 32 reduced Salmonella up to 0.94 log10 CFU/ml 24 h after co-inoculation. Twenty-eight LAB isolates that exhibited the highest inhibitory effect among pathogens were further analyzed to determine their antimicrobial resistance profile, adhesion potential, and cytotoxicity to Caco-2 cells. All LAB strains tested were susceptible to ampicillin, linezolid, and penicillin. Twenty-six were able to adhere to Caco-2 cells, five were classified as highly adhesive with > 40 bacterial cells/Caco-2 cells. Low cytotoxicity percentages were observed for the candidate LAB strains with values ranging from -5 to 8%. Genotypic identification by whole genome sequencing confirmed all as members of the LAB group; Enterococcus was the genus most frequently isolated with 21 isolates, followed by Pediococcus with 4, and Lactobacillus with 3. In this study, a systematic approach was used for the improved identification of novel LAB strains able to exert antagonistic effect against important foodborne pathogens. Our findings suggest that the selected panel of LAB probiotic strains can be used as biocontrol cultures to inhibit and/or reduce the growth of L. monocytogenes, Salmonella, and E. coli O157:H7 in different matrices, and environments.

In-Plant Validation Study of Harvest Process Controls in Two Beef Processing Plants in Honduras.

Imported meat in the United States can become a food safety hazard if proper food safety programs are not fully implemented in foreign meat processing plants. Thus, exporting countries' food safety inspection systems must be equivalent to the U.S. federal inspection system to become eligible to export meat to the United States. The objective of this study was to validate the beef harvest Hazard Analysis and Critical Control Points and food safety programs of two beef processing plants in Honduras operating under U.S. equivalency standards by evaluating the presence of Salmonella (plant A) and Shiga toxin-producing Escherichia coli (STEC; plant B) on hides. Additionally, evaluating pathogen transfer from hides to carcasses, as detected by preevisceration sampling, and the mitigation of transferred pathogens, by application of carcass spray interventions and determination of Salmonella presence in lymph nodes, was also conducted. In plant A, the presence of Salmonella on hides ( n = 30 of 687; 4.4%) was significantly greater ( P < 0.10) than on carcasses swabbed at preevisceration ( n = 7 of 687; 1.0%), after intervention ( n = 13 of 678; 1.9%), and in lymph nodes ( n = 14 of 691; 2.0%). In plant B, Salmonella was not detected on hide samples; therefore, data could not be used for validation of the harvest Hazard Analysis and Critical Control Points program. Alternatively, STEC presence on hides ( n = 21 of 85; 24.7%) was greater ( P < 0.10) than on carcasses at preevisceration ( n = 3 of 85; 3.5%) and after intervention ( n = 1 of 85; 1.2%). Pathogen presence in plant B did not differ ( P = 0.306) between carcasses in preevisceration and postintervention stages; both, however, were substantially low. Both plants' controls effectively reduced Salmonella and STEC presence in postintervention carcasses.