VALIDATION OF THE EFFECT OF INTERVENTIONS AND PROCESSES ON PERSISTENCE OF PATHOGENS ON FOODS
Location: Food Safety and Intervention Technologies
Title: Behavior of foodborne pathogens in Teewurst raw spreadable sausage
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 2007
Publication Date: September 16, 2007
Citation: Dourou, D., Porto Fett, A.C., Shoyer, B.A., Luchansky, J.B. 2007. Behavior of foodborne pathogens in Teewurst raw spreadable sausage. Meeting Abstract. PB3.
Teewurst is a traditional raw spreadable sausage of Germanic origin that is widely consumed in different countries worldwide including the United States. According to the USDA/FSIS Food Standards and Labeling Policy Book teewurst is an uncooked product processed with or without curing that is cold smoked for two to five days. It is characterized by a soft spreadable texture. Teewurst is typically made of pork, beef, pork bellies and bacon. Consumption of teewurst should be accompanied by thorough cooking according to USDA/FSIS regulations and policies. Consumers’ unawareness about the need to cook the product has led to foodborne illnesses. In this study, different multifactorial experiments were set up to assess the behavior of three different foodborne pathogens in teewurst. Five-strain cocktails of Salmonella typhimurium or Listeria monocytogenes and a three-strain cocktail of Escherichia coli 0157:H7 (ca. 5 log10 cfu/g each cocktail) were used to inoculate teewurst. Two sets of experiments were performed in triplicate by inoculating either the batter prior to stuffing or the surface of slices (ca. 20g each) of the finished product. Inoculated samples were stored at 1.5 degree, 4 degree, 10 degree and 21 degree C for up to 21 days. Additionally, the effect of nisin (5.5 and 6.93 ppm) added to teewurst batter on L. monocytogenes or E. coli (ca. 6 log10 CFU/g each) was also studied during storage at 4 degree and 10 degree C. In experiments where the pathogens were applied to the surface of finished product, the results for all four temperatures showed a decrease of ca. 0.9 to 1.4, 1.5 to 2.0, and 2.4 to 3.0 log10 CFU/g over the course of 21 days for E. coli, S. typhimurium, and L. monocytogenes, respectively. In experiments in which the pathogens were inoculated into the batter prior to stuffing, levels decreased ca. 3.3 to 4.5 log10 CFU/g for E. coli, 4.5 log10 CFU/g for Salmonella, and 2.6 to 4.6 log10 CFU/g for L. monocytogenes. There was no apparent difference in the extent of pathogen reduction with respect to storage temperature, regardless of inoculation method or pathogen. As expected, there was some variation in the level of reduction among replicates. The addition of nisin resulted in an initial 1.7 log10 CFU/g decrease of L. monocytogenes levels, but thereafter pathogen levels increased by 0.2 to 0.8 log10 CFU/g after nine days of storage at 4 degrees and 10 degrees C. In contrast, there was no appreciable change in E. coli levels, regardless of nisin concentration or temperature, after nine days of storage. Chemical analyses revealed significant differences in the salt, nitrite, fat, and carbohydrate levels in teewurst among product tested from 6 manufacturers. These results indicate that addition of nisin does result in an initial, albeit transient, decrease in levels of L. moncytogenes during storage at 4 degree and 10 degree C. These data also show that teewurst does not provide a favorable environment for E. coli O157:H7, Salmonella spp., or L. monoctyogenes inoculated in or on the product.