Natural glycolipids as a surface treatment prevent fungal spoilage of fermented sausages during ripening

Abstract

Raw fermented sausages are susceptible to fungal contamination during their production, which involves fermentation and ripening in controlled environments. Commonly used preservatives, such as sorbate and natamycin, raise concerns regarding potential health impact and cross resistance development, respectively. This study investigated the efficacy of natural microbial glycolipids as surface treatment for controlling fungal growth on fermented sausages in fiber and collagen casings. A 0.1 % (w/v) glycolipid solution performed similarly to a solution of natamycin at the same concentration in terms of suppression of fungal counts in both types of casings. The addition of 2.5 % (v/v) lactic acid to the 0.1 % (w/v) glycolipids solution tended to further delay the development of fungal growth. Furthermore, glycolipids prevented the visible growth of any contaminants on the surface of the casings. In contrast, heavy growth was observed on natamycin treated and on untreated sausages. Metagenomic analysis of the casing surface microbiota showed no difference in the fungal profile between treatments but higher abundance of staphylococci on the natamycin treated casings compared to the glycolipid treated ones. Staphylococcus xylosus was identified as the dominant organism exclusively on natamycin treated sausages, probably stemming from the starter culture. These results suggest that natural glycolipids, especially in combination with lactic acid, are an alternative to natamycin for controlling surface microbial contamination during ripening of raw fermented sausages.