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.

Survival of Escherichia coli O157:H7 after application of lactic acid bacteria.

BACKGROUND: Establishing novel preharvest intervention strategies for leafy green growers is of critical need with the rise in foodborne outbreaks associated with these products. Recent studies have shown that lactic acid bacteria (LAB) are able to reduce the presence of Escherichia coli O157:H7 in various food matrices. Electrostatic application of organic acids has been shown to be effective as a postharvest safety intervention to reduce E.coli O157:H7 on leafy greens. The effect of LAB electrostatically applied and sprinkler irrigated once over a 4 week growth cycle was evaluated against E. coli O157:H7 on spinach. RESULTS: The results indicated that E. coli O157:H7 when applied once during the 4 week growth cycle will survive in the soil and spinach leaves at harvest. LAB applied electrostatically and by sprinkler irrigation water on the soil and/or leaf surface within the first 4 weeks of the growing cycle resulted in a significant reduction (almost a 3 log10 reduction) of E. coli O157:H7 both on the leaf and in the soil at harvest, regardless of the application time (P < 0.01). CONCLUSION: LAB surface treatments have the potential to improve the safety of leafy green plants as a preharvest food safety intervention when combined with good agricultural practices. © 2018 Society of Chemical Industry.

Corn-Based Distillers' Grains in Diets for Feedlot Cattle Are Associated with the Burden of Escherichia coli O157 in Feces.

Inclusion of distillers' grains (DGs) has been associated with increased prevalence of Escherichia coli O157:H7 in cattle housed in research settings. Our objective was to quantify the relationship between inclusion of DGs in commercial feedlot rations and the burden of E. coli O157. A convenience sample of 10 feedlots was enrolled based on DG use in finishing diets; 1 cohort included 5 feedlots in which DGs were greater than 15% of the dietary dry matter and the other cohort consisted of 5 feedlots at a concentration less than 8%. Sampling occurred at each feedlot on four occasions at ∼6-week intervals. At each feedlot visit, 4 pens of cattle within 3 weeks of slaughter were selected and 24 freshly voided fecal pats were sampled. Ten-gram samples were enriched in 90 mL of modified tryptic soy broth with novobiocin (20 mg/L) for 14 h at 42°C. Enrichments were subjected to immunomagnetic separation, plating onto chromogenic agar with novobiocin (5 mg/L) and potassium tellurite (2.5 mg/L), incubation for 18 h at 37°C, and latex agglutination of morphologically typical colonies. E. coli O157 was recovered from 16.7% of 3840 samples. Adjusted prevalence was 14.3% after controlling for within-feedlot and within-pen clustering. Prevalence during each sampling period was 19.9% (round 1), 21.0% (round 2), 14.1% (round 3), and 11.7% (round 4). Prevalence varied between cohorts, but this difference varied over time (p = 0.06). Among those with greater than 15% of the diet as DGs, prevalence was greater than those with less than 8% inclusion for all rounds of sampling (p < 0.01). Averaged across time, prevalence was 23.9% and 9.4% for those with greater than 15% and those with less than 8% of DGs, respectively. While observational, these data provide real-world support of reports of increased E. coli O157:H7 burden associated with DG use in cattle diets.

Host responses to the pathogen Mycobacterium avium subsp. paratuberculosis and beneficial microbes exhibit host sex specificity.

Differences between microbial pathogenesis in male and female hosts are well characterized in disease conditions connected to sexual transmission. However, limited biological insight is available on variances attributed to sex specificity in host-microbe interactions, and it is most often a minimized variable outside these transmission events. In this work, we studied two gut microbes-a pathogen, Mycobacterium avium subsp. paratuberculosis, and a probiotic, Lactobacillus animalis NP-51-and the interaction between each agent and the male and female gastrointestinal systems. This trial was conducted in BALB/c mice (n=5 per experimental group and per sex at a given time point), with analysis at four time points over 180 days. Host responses to M.avium subsp. paratuberculosis and L. animalis were sensitive to sex. Cytokines that were significantly different (P ≤ 0.05) betweenthe sexes included interleukin-1α/ß (IL-1α/ß), IL-17, IL-6, IL-10, IL-12, and gamma interferon (IFN-) and were dependent on experimental conditions. However, granulocyte-macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF), and IL-13/23 showed no sex specificity. A metabolomics study indicated a 0.5- to 2.0-fold (log2 scale) increase in short-chain fatty acids (butyrate and acetate) in males and greater increases in o-phosphocholine or histidine from female colon tissues; variances distinct to each sex were observed with age or long-term probiotic consumption. Two genera, Staphylococcus and Roseburia, were consistently overrepresented in females compared to males; other species were specific to one sex but fluctuated depending on experimental conditions. The differences observed suggest that male and female gut tissues and microbiota respond to newly introduced microorganisms differently and that gut-associated microorganisms with host immune system responses and metabolic activity are supported by biology distinct to the host sex.

Influence of casein hydrolysates on exopolysaccharide synthesis by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus.

BACKGROUND: A lot of interesting research has been undertaken to enhance the yield of exopolysaccharides (EPS) produced by lactic acid bacteria (LAB). The objective of this study was to determine the influence of casein hydrolysates (CH) with molecular weight less than 3 kDa on cell viability, EPS synthesis and the enzyme activity involved in EPS synthesis during the co-culturing of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in MRS broth for 72 h at 37 ± 0.1 °C. RESULTS: The highest EPS yield (150.1 mg L⁻¹) was obtained on CH prepared with papain (CHP) at 48 h. At 24 h, EPS were composed of galactose, glucose and rhamnose in a molar ratio of 1.0:2.4:1.5. The monosaccharide composition changed with extension of the fermentation time. The activities of α-phosphoglucomutase, uridine 5'-diphosphate (UDP)-glucose pyrophosphorylase and UDP-galactose 4-epimerase were associated with EPS synthesis. Moreover, the activities of ß-phosphoglucomutase and deoxythymadine 5'-diphosphate (dTDP)-glucose pyrophosphorylase involved in rhamnose synthesis were very low at the exponential growth phase and could not be detected during other given periods. CONCLUSION: The influence of different CH (<3 kDa) on LAB viability, EPS production, EPS monomeric composition and activity levels of key metabolic enzymes was distinct. Besides, their influence was related to the distribution of amino acids.

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.

Salmonella Prevalence and Quantification in Market Hog Lymph Nodes and Tonsils in Several Regions and Seasons of the United States.

Market hog lymph nodes (LNs) can contaminate carcasses with Salmonella, as well as ground and comminuted pork products. The objective of this study was to perform a qualitative and quantitative analysis of LNs from several regions and seasons in the United States to establish a Salmonella prevalence and concentration baseline. Six types of LNs (axillary, mesenteric, subiliac, tracheobronchial, superficial inguinal, prescapular), and tonsils were sampled from market hog carcasses from different regions (east, central, and west) and seasons (winter, spring, and summer/fall). Salmonella was detected and enumerated using BAX®-System-SalQuant® methods and the BAX®-System Real-Time Salmonella Assay. Salmonella prevalence (N = 4,132) was 36% for tonsils, 35% for mesenteric LN, and less than 10% for the other LN types. Of the 601 carcasses tested, 62% were positive for Salmonella, with the highest prevalence occurring during spring in the east (90.9%), and the lowest prevalence occurring during spring in the central region (26.0%). Tonsil prevalence was greatest in the eastern region during spring. Mesenteric LN prevalence was high (>20%) regardless of season or region. Salmonella prevalence in tracheobronchial, subiliac, axillary, and superficial inguinal LNs was generally greatest during the spring or fall and in the eastern region. The median SalQuant® Salmonella concentration was 2.18 log10Salmonella cells/sample. Median SalQuant® concentration for all other sample types fell below the limit of quantification (1 log10Salmonella cells/sample). This longitudinal study can be used by the pork industry for risk assessments and risk-based decision-making.

Substantial within-animal diversity of Salmonella isolates from lymph nodes, feces, and hides of cattle at slaughter.

Lymph nodes (mandibular, mesenteric, mediastinal, and subiliac; n = 68) and fecal (n = 68) and hide (n = 35) samples were collected from beef carcasses harvested in an abattoir in Mexico. Samples were analyzed for Salmonella, and presumptive colonies were subjected to latex agglutination. Of the isolates recovered, a subset of 91 was characterized by serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility phenotyping. Salmonella was isolated from 100% (hide), 94.1% (feces), 91.2% (mesenteric), 76.5% (subiliac), 55.9% (mandibular), and 7.4% (mediastinal) of samples. From the 87 typeable isolates, eight Salmonella enterica serotypes, including Kentucky (32.2%), Anatum (29.9%), Reading (17.2%), Meleagridis (12.6%), Cerro (4.6%), Muenster (1.1%), Give (1.1%), and Mbandaka (1.1%), were identified. S. Meleagridis was more likely (P = 0.03) to be recovered from lymph nodes than from feces or hides, whereas S. Kentucky was more likely (P = 0.02) to be recovered from feces and hides than from lymph nodes. The majority (59.3%) of the Salmonella isolates were pansusceptible; however, multidrug resistance was observed in 13.2% of isolates. Typing by PFGE revealed that Salmonella strains generally clustered by serotype, but some serotypes (Anatum, Kentucky, Meleagridis, and Reading) were comprised of multiple PFGE subtypes. Indistinguishable PFGE subtypes and, therefore, serotypes were isolated from multiple sample types, and multiple PFGE subtypes were commonly observed within an animal. Given the overrepresentation of some serotypes within lymph nodes, we hypothesize that certain Salmonella strains may be better at entering the bovine host than other Salmonella strains or that some may be better adapted for survival within lymph nodes. Our data provide insight into the ecology of Salmonella within cohorts of cattle and offer direction for intervention opportunities.

Effects of the probiotic Lactobacillus animalis in murine Mycobacterium avium subspecies paratuberculosis infection.

BACKGROUND: MAP is a suspected zoonotic pathogen and the causative agent of Johne's Disease in cattle and other ruminant animals. With over $1 billion dollars in loss to the dairy industry due to Johne's Disease, efforts to eliminate or reduce MAP from cattle are of importance. The purpose of this study was to determine if daily intake of probiotics could eliminate or reduce Johne's Disease associated symptoms and pathogenesis by MAP. Post infection, animals are often asymptomatic carriers with limited shedding of the pathogen, proving early detection to be difficult. Disease and symptoms often appear 3-4 years after infection with antibiotic treatment proving ineffective. Symptoms include chronic gastrointestinal inflammation leading to severe weight-loss from poor feed and water intake cause a wasting disease. These symptoms are similar to those found in individuals with Crohn's Disease (CD); MAP has been implicated by not proven to be the causative agent of CD. Probiotics administered to livestock animals, including dairy and beef cattle have demonstrated improvements in cattle performance and health. Our objectives included determining the benefits of Lactobacillus animalis (strain name: NP-51) in MAP infected BALB/c mice by evaluating systemic and gastrointestinal response by the host and gut microbiota. Male and female animals were fed 1×106 CFU/g probiotics in sterile, powdered mouse chow daily and infected with 1 × 107 CFU/ml MAP and compared to controls. Animals were evaluated for 180 days to assess acute and chronic stages of disease, with sample collection from animals every 45 days. MAP concentrations from liver and intestinal tissues were examined using real time-PCR methods and the expression of key inflammatory markers were measured during MAP infection (interferon-gamma [IFN-Υ], Interleukin-1α, IL-12, IL-10, IL-6, and Tumor necrosis factor alpha [TNF-α]). RESULTS: Our results demonstrate administration of probiotics reduces production of IFN-Υ and IL-6 while increasing TNF-α and IL-17 in chronic disease; healthful immune responses that reduce chronic inflammation associated to MAP infection. CONCLUSIONS: We observed that the immune system's response in the presence of probiotics to MAP contributes towards host health by influencing the activity of the immune system and gut microbial populations.

Cross-sectional study examining Salmonella enterica carriage in subiliac lymph nodes of cull and feedlot cattle at harvest.

Bovine peripheral lymph nodes (LNs), including subiliac LNs, have been identified as a potential source of human exposure to Salmonella enterica, when adipose trim containing these nodes is incorporated into ground beef. In order to gain a better understanding of the burden of S. enterica in peripheral LNs of feedlot and cull cattle, a cross-sectional study was undertaken in which 3327 subiliac LNs were collected from cattle at harvest in seven plants, located in three geographically distinct regions of the United States. Samples were collected in three seasons: Fall 2010, Winter/Spring 2011, and Summer/Fall 2011. A convenience sample of 76 LNs per day, 2 days per season (approximately 1 month apart), was collected per plant, from carcasses held in the cooler for no less than 24 h. Every 10(th) carcass half on a rail was sampled, in an attempt to avoid oversampling any single cohort of cattle. Median point estimates of S. enterica contamination were generally low (1.3%); however, median Salmonella prevalence was found to be greater in subiliac LNs of feedlot cattle (11.8%) compared to those of cull cattle (0.65%). Enumeration analysis of a subset of 618 feedlot cattle LNs showed that 67% of those harboring S. enterica (97 of 144) did so at concentrations ranging from <0.1 to 1.8 log10 CFU/g, while 33% carried a higher burden of S. enterica, with levels ranging from 1.9 to >3.8 log10 CFU/g. Serotyping of S. enterica isolated identified 24 serotypes, with the majority being Montevideo (44.0%) and Anatum (24.8%). Antimicrobial susceptibility phenotypes were determined for all isolates, and the majority (86.1%) were pansusceptible; however, multidrug-resistant isolates (8.3%) were also occasionally observed. As Salmonella contained within LNs are protected from carcass interventions, research is needed to define opportunities for mitigating the risk of Salmonella contamination in LNs of apparently healthy cattle.

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.

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.

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.

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.

Salmonella diversity and burden in cows on and culled from dairy farms in the Texas High Plains.

The objective of this study was to characterize the epidemiology of Salmonella carried by dairy cows culled from herds in the Texas High Plains. Feces were collected from a convenience sample of 706 animals culled from nine dairy farms. In addition, individually paired fecal and hide samples were collected from 70 healthy milking cows on three of the dairies. Samples were cultured for Salmonella using routine methods; isolates were serotyped and subjected to a panel of antimicrobial drugs to determine susceptibility. Salmonella was recovered from 32.6% of culled cows. Whole-herd use of a vaccine containing siderophore receptors and porin proteins was associated (p=0.05) with reduced Salmonella prevalence in that the prevalence among herds that practiced whole-herd vaccination was 8.0% compared to 36.8% among herds that did not use this vaccine. The majority (88.6%) of isolates were pansusceptible or resistant to one drug. Of the 3.1% of isolates resistant to more than four drugs, all were Salmonella Newport and were recovered from one dairy. Various serotypes were recovered from individual fecal and hide samples. Salmonella Montevideo was recovered more frequently (p<0.01) from hide samples, whereas Salmonella Cerro was recovered more frequently (p<0.01) from feces. Salmonella was recovered from at least one cow on all dairies. While our study was not a priori designed to address herd-level factors, we found evidence that the whole-herd use of a siderophore receptor and porin protein-containing vaccine might be a useful aid in the control of Salmonella in groups of cattle. As this is a nonrandomized evaluation of an intervention, other herd-level factors that may be correlated with vaccine use, such as biosecurity, might have been responsible for the observed association.

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.

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.

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.

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.