Antibacterials and Natural Antifungals

Project entitled:

Exploiting the Antibacterial and Antifungal Properties of Whey Protein Hydrolysates

Summary

The development of new natural antimicrobials that may reduce the incidence of pathogens in food and prolong its shelf life remains an urgent issue in the food industry, including the dairy sector. The goal of this project is to identify, characterize and exploit new food antimicrobials for long-term dairy product conservation, replacing conventional additives. Various peptide fractions were obtained either by enzymatic hydrolysis of whey protein or by aqueous extraction from various cheese matrices. Analyzing the biological activity of these fractions showed significant inhibitory bactericidal or bacteriostatic activity against Listeria and Escherichia coli. Bacterial reductions of up to 5 logs were achieved, particularly with mozzarella and Gouda cheese extracts. The most active fractions were subjected to physicochemical and molecular characterization. In addition, a pilot process of fractionation and concentration through nanofiltration was developed for the large-scale preparation of a peptide fraction with strong inhibitory activity. The antimicrobial activity of the product obtained was validated in a model curd against L. monocytogenes. New high added-value products were thus developed and can be used as bioconservation agents in the dairy industry. This approach is not only an insurance policy for consumers, but also a proof of quality that would enhance the reputation of Canadian dairy products and therefore their profitability.