Selective effect of the product type and the packaging conditions on the species of lactic acid bacteria dominating the spoilage microbial association of cooked meats at 4°C

The product type was shown to strongly affect the growth rate and the composition of the spoilage lactic flora during refrigerated (4 degrees C) storage of cooked, cured meats, sharing their processing plant environment, day of production and film packaging conditions. Growth of lactic acid bacteria (LAB) under vacuum was more prolific on the product in the order: ham > turkey breast fillet > smoked pork loin > pariza > mortadella > bacon, and ham > frankfurters, manufactured in two industrial meat plants A and B, respectively. The Lactobacillus sakei/curvatus group prevailed in all products, except the non-smoked, boiled whole-meats, i.e. cooked ham and turkey breast fillet, where Leuconostoc mesenteroides subsp. mesenteroides predominated. Lactobacillus sakei was by far the most prevalent species in smoked whole-meats, i e pork loin and bacon. Emulsion sausages, i e. pariza, mortadella and frankfurters, contained a more diverse lactic flora. Leuconostoc carnosum and Lc. citreum occurred in boiled, whole-meats and emulsion sausages, respectively. Weissella viridescens was isolated from smoked meat products only. A very good correlation between the LAB growth and types and important intrinsic factors, such as the product pH, moisture, salt (brine) concentration and cooking method could be observed. When ham and frankfurters from plant B were stored in air, yeasts and mainly Brochothrix thermosphacta became important members of the spoilage association Growth of LAB was faster in air. The presence of oxygen resulted in a replacement of Lc. mesenteroides subsp. mesenteroides by other Leuconostoc spp in ham, and in a shift of the spoilage flora from homo- to heterofermentative LAB species in frankfurters. (C) 2000 Academic Press.