FATE OF LISTERIA-MONOCYTOGENES AND PEDIOCOCCAL STARTER CULTURES DURING THE MANUFACTURE OF CHICKEN SUMMER SAUSAGE

Two formulations of chicken summer sausages [100% hand deboned chicken meat (HDCM) and 85% HDCM and 15% chicken hearts (HDCM-CH)] were prepa red with a nonpediocin-producing (PED-) Pediococcus acidilactici start er culture and inoculated with 10(4) or 10(7) cfu of a five-strain mix ture of Listeria monocytogenes/g of batter. Sausages were fermented to pH 5.0 (11 h), cooked to an internal temperature of 66.5 C, cold-show ered, and stored at 4 C (60 days) and 30 C (7 days). For both formulat ions and inoculation levels, L. monocytogenes populations decreased 1. 3 to 1.8 log10 cfu/g by the end of fermentation. No L. monocytogenes o rganisms were recovered from sausages (by enrichment) following the co ok and shower or storage at 4 or 30 C. In contrast, P. acidilactici in creased .7 to 1.2 log10 cfu/g during fermentation, and <10(2) cfu/g re mained after the cook and shower and storage at 4 and 30 C. In a secon d set of experiments, sausages (HDCM) were prepared with a PED- or a p ediocin-producing (PED+) P. acidilactici starter culture and challenge d with the L. monocytogenes mixture (10(7) cfu/g) The PED- culture red uced numbers of L. monocytogenes 1.2 log10 cfu/g during fermentation, whereas L. monocytogenes numbers declined 2.6 log10 cfu/g in the prese nce of the PED+ culture. Although acid production by both starter cult ures was equivalent, greater inhibition of L. monocytogenes by the PED + compared with the PED- starter culture was attributed to in situ pro duction of pediocin. Pediococcal starter cultures and proper cooking e liminated L. monocytogenes from sausages and established that PED+ cul tures provide an additional hurdle against poultry-related listeriosis .