The effect of reduced sodium chloride content on the microbiological and biochemical properties of a soft surface-ripened cheese

Many health authorities have targeted salt reduction in food products as a means to reduce dietary sodium intake due to the harmful effects associated with its excessive consumption. In the present work, we evaluated the effect of reducing sodium chloride (NaCl) content on the microbiological and biochemical characteristics of an experimental surface-ripened cheese. A control cheese (1.8% NaCl) and a cheese with a reduced NaCl content (1.3% NaCl) were sampled weekly over a period of 27 d. Reducing NaCl content induced microbial perturbations such as the lesser development of the yeast Debaryomyces hansenii and the greater development of the gram-negative bacterium Hafnia alvei. This was accompanied by changes in proteolytic kinetics and in profiles of volatile aroma compounds and biogenic amine production. Finally, the development of the spoilage microorganism Pseudomonas fragi was significantly higher in the cheese with a reduced salt content

Structure–Function Relationships of Microbial Communities

International audienceMicrobial community structure is the result of environmental conditions that vary significantly and frequently. In laboratory conditions, associations from two microorganisms to complex microbial communities are used to mimic real ecosystems and their functions. Nevertheless, the composition of individual members of complex ecosystems and their relationships, as well the environmental conditions needed to re-create microcosms and their associated activities, are hard to reproduce. The present chapter gives a laboratory-based methodological approach to study structure-function relationships. The results obtained from a systematic study of various ecosystems and the extent of environmental conditions that dictate the structure of communities and the link with ecosystem function are discussed. We also comment on, to what extent the results obtained in laboratory conditions are transposable to natural ecosystems. Finally, three specific case-studies related to cheese ripening are developed to illustrate how microbial ecology can be integrated into food microbiology for better quality and safety of smear cheeses