BEHAVIOR OF LISTERIA-MONOCYTOGENES IN WIENER EXUDATES IN THE PRESENCE OF PEDIOCOCCUS-ACIDILACTICI-H OR PEDIOCIN-ACH DURING STORAGE AT 4-DEGREES-C OR 25-DEGREES-C

Exudative fluids were collected from packages of five brands of all-beef wieners and inoculated to contain 10(4) to 10(5) CFU of a three-strain (Scott A, V7, and 101M) mixture of Listeriae were inactivated (decrease of 0.61 to 3.8 log10 CFU/ml) in all five exudates held at 4-degrees-C for 29 days. L. monocytogenes grew (increase of 1.7 to 3.6 log10 CFU/ml) in two of five exudates held at 25-degrees-C for 6 days. Exudate was inoculated with a derivative of Pediococcus acidilactici H (designated JBL1095) or treated with pediocin AcH (a bacteriocin) as a novel approach to control the growth of L. monocytogenes in wiener exudates. Initially, pediocin AcH caused rapid death (decrease of 0.74 log10 CFU/ml in 2 h) of L. monocytogenes in exudate held at 4-degrees-C, but thereafter the inactivation was similar to that in control exudate (L. monocytogenes only) or exudate containing L. monocytogenes plus JBL1095. At 25-degrees-C, L. monocytogenes grew in the presence of JBL1095 during the first 64 h of incubation, but thereafter the numbers of the pathogen decreased appreciably (5.84 log10 CFU/ml in 3 days). In the presence of pediocin AcH, there was a gradual decrease in numbers of L. monocytogenes throughout the storage period of 25-degrees-C. These data indicate that added biopreservatives can potentiate and amplify the intrinsic listeriostatic or listericidal activity of wiener exudate.