Positive effects of growth at suboptimal temperature and high salt concentration on long-term survival of Lactobacillus sakei

Abstract

Lactobacillus sakei is a lactic acid bacterium commonly found on fresh meat and represents the predominant flora of vacuum-packed meat. In the present article, we studied the behavior of L. sakei in a chemically defined medium under various growth conditions relative to temperature or NaCl concentration. Growth occurred at each temperature, but growth rate and final cell density decreased at low temperature and survival was enhanced. In the presence of NaCl, we also observed a longer doubling time and a lower final cell density together with an enhanced long-term survival. When both conditions were combined, the long-term survival was greatly increased to about 28 weeks. Differences in cell morphology were observed under electron microscopy when cells were grown at low temperature in the presence of salt. We speculate that these are due to modifications in membrane structure. These results show that L. sakei is able to adapt to these environmental conditions and that slow growth is clearly associated with enhanced long-term survival.