SURVIVAL OF ESCHERICHIA-COLI O157-H7, LISTERIA-MONOCYTOGENES AND SALMONELLA KENTUCKY IN NORWEGIAN FERMENTED, DRY SAUSAGE

Raw, newly produced sausages containing a mixed starter culture of lac tobacilli and micrococci were each inoculated at separate locations (u sing a syringe) with low (10(3)-10(4) cfu) and high ( 10(4)-10(7) cfu) numbers of either Escherichia coli 0157:H7, Listeria monocytogenes or Salmonella kentucky. Three identically prepared sausages were analyse d at each sampling day during fermentation, maturation and storage at 4 and 20 degrees C. In the low-inoculum samples, growth was observed i nitially (2 days) during fermentation for E. coli 0157:H7 (3 log(10) i ncrease in cfu) and L. monocytogenes (five-fold increase in cfu) but n ot for S. kentucky which decreased below the detection limit (150 cfu sample(-1)). None of the pathogens was detected after 5.5 months, neit her at 4 nor 20 degrees C. In the high-inoculum samples there was a de crease during fermentation and maturation for all the pathogens. After 5.5-months storage at 4 degrees C, there was only about 90% reduction of the original inoculate of L. monocytogenes, whereas E. coli 0157:H 7 survived at a low number (500 cfu sample(-1)) and S. kentucky disapp eared below the detection limit. After 5.5-months storage at 20 degree s C, all the pathogens had disappeared below the detection limit. Thes e results indicate that, from a safety point of view, it may be better to store these kinds of sausages at room temperature than in the cold , provided that the sensory qualities are retained and that similar re sults are obtained with other food pathogens. (C) 1998 Academic Press.