Survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella kentucky in Norwegian fermented, dry sausage
1998
Nissen, H. | Holck, A.
Raw, newly produced sausages containing a mixed starter culture of lactobacilli and micrococci were each inoculated at separate locations (using a syringe) with low (10(3)-10(4) cfu) and high (10(5)-10(7) cfu) numbers of either Escherichia coli O157:H7, Listeria monocytogenes or Salmonella kentucky. Three identically prepared sausages were analysed at each sampling day during fermentation, maturation and storage at 4 and 20 degrees C. In the low-inoculum samples, growth was observed initially (2 days) during fermentation for E. coli O157:H7 (3 log10 increase in cfu) and L. monocytogenes (five-fold increase in cfu) but not for S. kentucky which decreased below the detection limit (150 cfu sample-1). None of the pathogens was detected after 5.5 months, neither at 4 nor 20 degrees C. In the high-inoculum samples there was a decrease 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 O157:H7 survived at a low number (500 cfu sample-1) and S. kentucky disappeared below the detection limit. After 5.5-months storage at 20 degree C, all the pathogens had disappeared below the detection limit. These 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 results are obtained with other food pathogens.
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