Escherichia coli O157:H7 strains that persist in feedlot cattle are genetically related and demonstrate an enhanced ability to adhere to intestinal epithelial cells.

A longitudinal study was conducted to investigate the nature of Escherichia coli O157:H7 colonization of feedlot cattle over the final 100 to 110 days of finishing. Rectal fecal grab samples were collected from an initial sample population of 788 steers every 20 to 22 days and microbiologically analyzed to detect E. coli O157:H7.

Manual squeezing as an alternative to mechanical stomaching in preparing beef carcass sponge samples for microbiological analysis.

The U.S. Department of Agriculture (USDA) requires beef abattoir operators to periodically analyze beef carcass sponge samples for levels of Escherichia coli.

Use of Enterobacteriaceae analysis results for predicting absence of Salmonella serovars on beef carcasses.

Previous work using a large data set (no. 1, n = 5355) of carcass sponge samples from three large-volume beef abattoirs highlighted the potential use of binary (present or absent) Enterobacteriaceae results for predicting the absence of Salmonella on carcasses. Specifically, the absence of Enterobacteriaceae was associated with the absence of Salmonella.

Evaluation of potential for inhibition of growth of Escherichia coli O157:H7 and multidrug-resistant Salmonella serovars in raw beef by addition of a presumptive Lactobacillus sakei ground beef isolate.

The efficacy of adding presumptive Lactobacillus sakei (LS) strain 10-EGR-a, the most inhibitory from among 12 ground beef Lactobacillus isolates, to inhibit growth by Escherichia coli O157:H7 and multidrug-resistant (MDR) Salmonella (serovars Newport and Typhimurium) was evaluated in a beef-derived broth medium at 10 degrees C and in fresh raw ground beef at 10 and 5 degrees C. Pathogen inhibition was observed in the broth medium at both high (10(8):10(5) to 10(7):10(5)) and low (10(6):10(5) to 10(5):10(5)) LS:pathogen ratios. After 9 days at 10 degrees C, in broth medium with high LS:pathogen ratios, growth of E.

Using indicator bacteria and Salmonella test results from three large-scale beef abattoirs over an 18-month period to evaluate intervention system efficacy and plan carcass testing for Salmonella.

To develop a process for predicting the likelihood of Salmonella contamination on beef carcasses, we evaluated the influence of several possible causative factors (i.e., year, abattoir, day of week, month, and intervention system components) on the risk of Salmonella and indicator organism contamination.