Foodborne Gastroenteritis Caused by Vibrio, Yersinia, and Campylobacter Species. Modern Food Microbiology. Boston: Springer US; 1996. pp. 544-65. [DOI: 10.1007/978-1-4615-7473-6_25]

Resistance of cold- and starvation-stressed Vibrio vulnificus to heat and freeze-thaw exposure

The effects of cold storage and starvation on the subsequent heat resistance and freeze-thaw resistance of Vibrio vulnificus were studied. Three strains of V. vulnificus were evaluated. Cold stress had no effect on freeze-thaw resistance (P > 0.05). Starvation enhanced freeze-thaw resistance for one strain compared to controls (P < 0.05). V. vulnificus was not heat resistant; control populations were inactivated within 12 min at 47 degrees C. Starvation increased heat tolerance for one strain, but differences were small from a processing perspective (P < 0.05). Cold stress had no effect on heat resistance (P > 0.05). Cold adaptation (holding 4 h at 15 degrees C) enhanced cold temperature (5 degrees C) tolerance. This information will be helpful in the development of methods to minimize V. vulnificus risk.

Extent of microbial contamination in United States pork retail products

To determine the extent of microbiological contamination of U.S. pork, 384 samples of retail pork were collected from 24 stores in six cities, including (i) whole-muscle, store-packaged pork; (ii) fresh, store-packaged ground pork and/or pork sausage; (iii) prepackaged ground pork and/or pork sausage; and (iv) whole-muscle, enhanced (injected or marinated; 60% store-packaged, 40% prepackaged) pork. Additional samples (n = 120) of freshly ground pork and/or pork sausage were collected from two hot-boning sow/boar sausage plants, two slaughter and fabrication plants, and two further-processing plants. Samples were analyzed for aerobic plate counts (APC), total coliform counts (TCC), Escherichia coli counts (ECC), and incidences of Salmonella spp., Listeria monocytogenes, Campylobacter jejuni, Campylobacter coli, and Yersinia enterocolitica. Mean log APC and TCC were highest (P < 0.05) for store-ground pork, while whole-muscle, enhanced products and prepackaged ground products had the lowest (P < 0.05) APC. Mean log APC and TCC were higher (P < 0.05) in samples from the slaughter and fabrication plants than in samples from hot-boning and further processing plants. Mean log ECC were lower (P < 0.05) in samples from further-processing plants compared to slaughter and fabrication plants and hot-boning, sow and boar sausage plants. L. monocytogenes was detected in 26.7% of plant samples and 19.8% of retail samples and was present more frequently in ground products. Y. enterocolitica was detected most often in whole-muscle, store-packaged cuts (19.8%) and in store-ground product (11.5%). Salmonella spp. were found in 9.6% of retail samples and 5.8% of plant samples, while C. jejuni and C. coli were found in 1.3% of retail samples and 6.7% of plant samples. Pork products exposed to the most handling and processing appeared to be of the poorest microbiological quality. These results should be useful in risk assessments that are directed at the identification of actions that could enhance food safety.