26/01/2017

ELENA DALZINI^1,3, ELISA GALUPPINI², DANIELA MERIGO², PAOLO-FELICE BUIZZA², MARINA-NADIA LOSIO², BARBARA BERTASI² and GIORGIO VARISCO¹

¹National Reference Centre for Emerging Risk in Food Safety, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini,"  Brescia, Italy
²Department of Food Microbiology, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini," Brescia, Italy

 

Journal of Food Processing and Preservation ISSN 1745-4549

 

© 2016 Wiley Periodicals, Inc. The aims of this study were to (1) study the optimal growth condition for two Lactococcus lactis strains to produce the anti-listeria compounds and (2) evaluate the effect of films activated with a twofold concentrated cell-free supernatant of La. lactis to inhibit Listeria monocytogenes. For the growth conditions, skimmed milk added to either Ml7 or MRS provided the highest levels of anti-listeria activity assayed (800 arbitrary unit per milliliter) for both La. lactis strains. A significant decrease of Li. monocytogenes counts was observed in cheese packed in films treated with an average decrease of 2.12 log colony-forming unit per gram after 15 days of storage. Practical Applications: The antimicrobial film for food packaging can be used for the preservation of perishable foods such as the sliced cheese. This film developed in our study inhibits Listeria monocytogenes growth in sliced cheese, and does not have an adverse effect on the lactic microbiota, contributing to the preservation of the quality of the product. Thus, it could be a useful tool for the control of the development of pathogens in foods during storage of dairy products.