A method of reducing the concentration of Gram-negative bacteria in a food product, comprising:
- adding to a food product a red wine extract produced from red wine by dealcoholization, concentration and drying, and a culture comprising at least one class IIa bacteriocin-producing lactic acid bacterial strain,
- ripening the food product, and
- storing the food product at a temperature of at most 15° C. until a concentration of Gram-negative bacteria of less than 1 CFU per 10 g food product is reached,
- wherein the Gram-negative bacteria are selected from Aeromonas caviae;
- Aeromonas hydrophila;
- Aeromonas sobria;
- Campylobacter jejuni;
- Citrobacter ssp.;
- Enterobacter ssp.;
- Escherichia coli enteroinvasive strains;
- Escherichia coli enteropathogenic strains;
- Escherichia coli enterotoxigenic strains;
- Escherichia coli O157:H7;
- Klebsiella ssp.;
- Plesiomonas shigelloides;
- Salmonella ssp.;
- Shigella ssp.;
- Vibrio cholerae;
- and Yersinia enterocolitica,
- wherein the method reduces the concentration of the Gram-negative bacteria in the food product to a greater extent than adding the class IIa bacteriocin-producing lactic acid bacterial culture and not the red wine extract.