Effects of natural compounds on food-related microorganisms

The aim was to identify natural compounds, alternative to antimicrobial chemical additives used in the fermented meat industry, able to inhibit spoilage microorganisms without affecting the growth of useful ones. Moreover, the effect of natural compounds on protein expression of different foodrelated bacteria was studied. The antimicrobial activity produced by natural compounds was detected by the agar well diffusion assay. The effectiveness of natural compounds in different concentrations was detected evaluating the microbial growth in meat broth medium. The effect of natural compounds on the protein expression of food related microorganisms was evaluated by electrophoresis with microfuidic techniques. The results evidenced that three natural compounds (Rosmarinus officinalis, Citrus compositum and Malpighia punicipholia) were the most effective in order to inhibit spoilage microorganisms such as Clostridium sporogenes, Brochothrix thermosphacta and Pseudomonas fluorescens, without affect the growth of Lactobacillus sakei, Staphylococcus xylosus and Kocuria varians, used as starter in fermented meat products. Electrophoresis evidenced that natural compounds are also able to affect the expression of the microbial protein pattern. The research produced promising results on the possibility to obtain innovative fermented meat products without chemical additives or with their reduction. Moreover, the results highlighted a relationship between the sensitivity/resistance of microorganisms to natural compounds and their whole-cell protein expression.