H. Nissen et A. Holck, SURVIVAL OF ESCHERICHIA-COLI O157-H7, LISTERIA-MONOCYTOGENES AND SALMONELLA KENTUCKY IN NORWEGIAN FERMENTED, DRY SAUSAGE, Food microbiology (Print), 15(3), 1998, pp. 273-279
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.