Occurrence of Brochothrix thermosphacta in meats of different species and the role of monosodium glutamate (MSG) in its spoilage potential in mortadella-type emulsified cooked sausage

When meats and meat products are vacuum-packed, aerobic Gram-negative psychrotrophic spoilage bacteria, especially Pseudomonas , are replaced by Gram-positive psychrotrophic bacteria, mainly Brochothrix and lactobacilli. Nowadays, there is a widespread use of monosodium glutamate (MSG) in meat formulations. This work aimed to investigate the role of MSG on the onset of defects related to B. thermosphacta growth in vacuum-packed raw meats as well as the effect of mortadella cooking process on Brochothrix and lactobacilli survival. B. thermosphacta showed greater growth in pork and lamb compared to beef, while the type of meat did not significantly influence lactobacilli growth. MSG did not influence growth of B. thermosphacta . The initial counts of B. thermosphacta and of Lactobacilli were similar, but showed a converse profile, with that of B. thermosphacta decreasing over storage. Brochothrix was not recovered from mortadella at post cooking stage. When cooked mortadella were inoculated with Brochothrix slime was detected after 20 days of storage.