Liver abscess etiology in feedlot steers involves the escape of bacteria from the digestive tract to form a polymicrobial abscess within or on the external surface of the liver. However, little is known about the effects of feedlot finishing systems on the microbial composition of the liver abscess purulent material. Liver abscesses were collected at the time of harvest from steers originating from a single feedlot managed in either a traditional program (which included tylosin phosphate supplementation) or a natural program (without tylosin phosphate supplementation). The purulent material of liver abscesses from traditionally managed steers (N = 53 abscesses) and that of naturally managed steers (N = 62 abscesses) was characterized using the V4 region of the 16S rRNA gene. Two phyla and three genera were found in greater than 1% relative abundance across all abscesses. The genus Fusobacterium was identified in all liver abscess samples and accounted for 64% of sequencing reads. Bacteroides and Porphyromonas genera accounted for 33% and 1% of reads, respectively. Trueperella was more likely to be found in the liver abscesses of naturally managed steers than traditionally managed steers (P = 0.022). Over 99% of the genus-level bacterial sequences observed across all liver abscesses belonged to Gram-negative genera. Bacteria known to colonize both the rumen and hindgut were identified within liver abscesses. No differences in alpha diversity or beta diversity were detected between liver abscess communities (between the two management programs or individual pens) when tested as richness, Shannon Diversity Index, or weighted UniFrac distances (P > 0.05). These results were consistent with previous identification of Fusobacterium necrophorum as the primary bacteriologic agent within liver abscesses and emphasized the relationship between the gastrointestinal microbiota and liver abscess formation. Though the microbiota of the liver abscess purulent material was similar between steers fed an antibiotic-free diet and those fed an antibiotic-containing diet from the same feedlot, divergence was detected in liver abscess communities with some being dominated by Fusobacterium and others being dominated by Bacteroides. As feedlot cattle consume grain, the rumen becomes more acidic. If the lining of the digestive tract is damaged, bacteria that normally remain in the digestive tract can enter the body. Certain bacteria like Fusobacterium necrophorum are involved in the formation of liver abscesses. Feedlot cattle are commonly fed an antibiotic (tylosin phosphate) to reduce the occurrence of liver abscesses, but increasing scrutiny is placed on the antibiotic use. However, the effect of eliminating the antibiotic used to prevent liver abscesses on the bacterial communities involved in liver abscess formation is unknown. This study compared the bacteria found within liver abscesses of cattle fed tylosin phosphate with that of cattle not fed tylosin phosphate. All liver abscesses contained F. necrophorum, and Bacteroides was the second most commonly identified bacterium. Trace amounts of bacteria known to colonize the mouth and digestive tract were observed. Trueperella, a bacteria targeted by tylosin phosphate, was found more frequently in liver abscesses from cattle that received no antibiotic. While the core bacterial composition of the liver abscess was unaffected by antibiotic supplementation to feedlot steers, reduced Trueperella in liver abscesses from cattle-fed tylosin phosphate could be related to a reduction in liver abscess prevalence.

African swine fever is a high-consequence foreign animal disease endemic to sub-Saharan Africa and the island of Sardinia. The U.S. is the world’s third largest pork producer, and ASF introduction would severely disrupt the pork supply chain, emphasizing the need to protect market access for U.S. proteins. However, niche producers raising swine intended for exhibition may not follow stringent biosecurity protocols, and livestock show circuits may promote untracked animal movement across the country, potentially exacerbating virus’ spread in the event of ASF incursion into the U.S. Youth membership in state or national swine organizations offers a route for outreach and educational activities to enhance foreign animal disease preparedness, and adult presence at swine exhibitions allows a wide variety of programming for all ages to better serve all levels of understanding.

The United States’ large-scale poultry meat industry is energy and water intensive, and opportunities may exist to improve sustainability during the broiler chilling process. By USDA regulation, after harvest the internal temperature of the chicken must be reduced to 40°F or less within 16 h to inhibit bacterial growth that would otherwise compromise the safety of the product. This step is accomplished most commonly by water immersion chilling in the United States, while air chilling methods dominate other global markets. A comprehensive understanding of the differences between these chilling methods is lacking. Therefore, we assessed the meat quality, shelf-life, microbial ecology, and techno-economic impacts of chilling methods on chicken broilers in a university meat laboratory setting. We discovered that air chilling methods resulted in superior chicken odor and shelf-life, especially prior to 14 days of dark storage. Moreover, we demonstrated that air chilling resulted in a more diverse microbiome that we hypothesize may delay the dominance of the spoilage organism Pseudomonas. Finally, a techno-economic analysis highlighted potential economic advantages to air chilling compared to water chilling in facility locations where water costs are a more significant factor than energy costs. IMPORTANCE As the poultry industry works to become more sustainable and to reduce the volume of food waste, it is critical to consider points in the processing system that can be altered to make the process more efficient. In this study, we demonstrate that the method used during chilling (air versus water chilling) influences the final product microbial community, quality, and physiochemistry. Notably, the use of air chilling appears to delay the bloom of Pseudomonas spp. that are the primary spoilers in packaged meat products. By using air chilling to reduce carcass temperatures instead of water chilling, producers may extend the time until spoilage of the products and, depending on the cost of water in the area, may have economic and sustainability advantages. As a next step, a similar experiment should be done in an industrial setting to confirm these results generated in a small-scale university lab facility.

Validated surrogates are a useful tool for studying the response of pathogens to food safety interventions, but better surrogates are needed for studies using high pressure processing. Ground beef (85% lean, 15% fat) was inoculated separately with mixed cultures of Escherichia coli O157, non-O157 Shiga toxin–producing E. coli, nontyphoidal Salmonella, and nonpathogenic E. coli surrogate bacteria. The inoculated ground beef was subjected to high hydrostatic pressures of 200, 400, and 600 MPa for 4, 6, and 8 min at each pressure. High pressure processing at 200 MPa reduced the inoculated populations of the pathogenic bacteria by 0.9 to 1.8 log CFU/g, 400 MPa reduced the inoculated populations by 2.5 to 3.6 log CFU/g, and 600 MPa reduced the inoculated populations by 4.5 to 5.6 log CFU/g. The nonpathogenic E. coli surrogates were more resistant to the effects of high pressure processing than were the inoculated pathogen populations. This finding suggests that the nonpathogenic E. coli surrogates cou...

The objective of this study was to assess the presence and characteristics of Salmonella enterica found in the synovial fluid of broiler carcasses. The synovial fluid of three individual joints from 500 broiler carcasses was individually sampled from five broiler processing facilities located in the Southeast and West regions of the United States (1,500 total samples). The external surface of broiler carcass was decontaminated before sampling of the shoulder, coxofemoral, and tibiofemoral joints. Individual samples were enriched, composited, and subjected to rapid PCR-based detection of Salmonella. Individual samples from any positive composites were also enriched before determination of Salmonella presence in the same manner. Positive individual samples were subjected to secondary enrichment before plating onto selective agar for isolation of Salmonella. Salmonella isolates were serotyped before determination of antimicrobial susceptibility. Overall, 1.00% (5 of 500 broiler carcasses) of composi...