Proteolytic and lipolytic changes in beef inoculated with spoilage microorganisms and bioprotective lactic acid bacteria

Abstract

The use of a controlled lactic fermentation has been studied by several authors as a means to extend meat shelf-life without notably altering its sensory quality. Growth and metabolite production by spoilage microorganisms as well as by bioprotective strains are influenced by storage conditions. The objective of this work was to study the effect of temperature and storage time upon the growth and metabolite production of four spoilage bacteria and three bioprotective lactic acid strains in vacuum packaged, finely cut beef. Lipolysis was mainly due to the presence of Brochothrix thermosphacta at 4°C and at 20°C, whereas proteolysis was mainly caused by pseudomonads. Presence of Lactobacillus minor, a heterofermentative strain, did not promote proteolysis nor lipolysis at either temperature. No considerable lipolysis was observed until day 8 of storage in samples inoculated with bioprotective strains, but increased at day 12 when stored at 20°C; no proteolysis was observed at any storage temperature.