Microbial formation of nitrite-cured pigment, nitrosylmyoglobin, from metmyoglobin in model systems and smoked fermented sausages by Lactobacillus fermentum strains and a commercial starter culture

Abstract

Two Lactobacillus fermentum strains (JCM1173 and IFO3956) were evaluated for their ability to generate nitrosylated derivatives of myoglobin either in broth media or fermented sausages. For comparison, a commercial starter culture was also included. All bacteria species investigated converted brown metmyoglobin into red myoglobin derivatives when incubated separately in broth, but only the two lactobacilli showed a signal for nitrosylmyoglobin as measured by electron spin resonance spectroscopy. In smoked sausages with added bacteria culture the highest amount of nitrosylmyoglobin was observed in the centre of sausage with added L. fermentum, but colour formation in sausages with 60 ppm of nitrite added was more pronounced. An outer peripheral zone of all fermented sausages contained levels of nitrosylmyoglobin comparable to nitrite-cured sausages. Nitrogenous gasses from smoke may, however, cause this zone to be formed. Depending on a further optimisation of the processing parameters, the bacteria's ability to generate NO could form the basis for production of cured meat products without the use of nitrite/nitrate.