Utilisation d’un ferment producteur de monoxyde d’azote comme alternative aux sels nitrites ?

Staphylococcus xylosus, a coagulase-negative Staphylococcus is usually used as a starter culture in meat products. It contributes to the reduction of nitrate to nitrite through its nitrate reductase activity that is crucial for color development. Nitrite is reduced to nitric oxide (NO), which binds to the meat pigment metmyoglobin to form the stable red nitrosomyoglobin. However, the safety of the use of nitrite regarding human health has been questioned. Therefore, alternatives to substitute nitrite are under investigation. The aim was to evaluate the ability of S. xylosus nitric oxide synthase (NOS) to produce NO, based on an assay in which metmyoglobin is converted to nitrosomyoglobin. A mutant strain deleted for nos (Δnos) has been generated. The ability of the Δnos mutant to form nitrosomyoglobin was sharply decreased compared to the wild-type and the nos complemented mutant, demonstrating the contribution of S. xylosus NOS in the production of NO. The NOS pathway needs to be further understood and could constitute a natural solution to substitute nitrite in meat products.