Antibacterial and antifungal activity of water-soluble extracts from Mozzarella, Gouda, Swiss, and Cheddar commercial cheeses produced in Canada

Abstract

The aim of this study was to evaluate the antibacterial and antifungal activities of water-soluble extracts (WSEs) from different types of cheeses against several food-borne pathogens. A total of five commercial cheeses manufactured in Canada were selected namely Mozzarella, Gouda, Swiss, and old and medium Cheddar. WSEs were ultrafiltrated through 10 kDa cutoff membranes and desalted using Sep-Pak cleanup column. Resulting peptide fractions were subject to physicochemical characterization and assessment for their antimicrobial activity against bacteria (Listeria ivanovii, Listeria monocytogenes, Escherichia coli MC4100, and E. coli O157:H7) and filamentous fungi (Aspergillus, Mucor, Fusarium, and Penicillium). Mozzarella and Gouda WSEs were the most active and inhibited with L. monocytogenes significantly, with respective reductions of 3.83 ± 0.15 and 2.93 ± 0.33 log. After desalting and organic acids removal, Mozzarella and Gouda WSEs produced 3-log reductions of L. ivanovii and E. coli MC4100, with minimal inhibitory concentration (MIC) values ranging 8.5–17 mg.mL−1. At a concentration of 34 mg.mL−1, all cheese peptidic WSEs induced a delay in spore germination. All WSEs were equally active against Fusarium sp., with a minimal concentration of 17 mg.mL−1. Gouda, Mozzarella, and medium Cheddar WSE were the strongest inhibitors in the case of Aspergillus versicolor and Mucor racemosus (17 mg.mL−1), whereas these spores were less sensitive to old Cheddar and Swiss WSE (34 mg.mL−1). This study demonstrates that peptidic WSEs of commercial cheeses manufactured in Canada exhibit antibacterial and antifungal activities, which may offer a promising alternative for purposes of food preservation.