Antimicrobial efficacy of a polyphenolic extract from olive oil by-product against "Fior di latte" cheese spoilage bacteria.

This study aimed to evaluate a polyphenol extract from olive oil by-product, to improve the preservation of "Fior di latte" cheese during storage. Nine batches of "Fior di latte" cheese were manufactured in a local dairy production plant: three batches treated with 250 μg/mL of phenols from olive oil by-products in the governing liquid; three batches treated with 500 μg/mL of phenols in the governing liquid, and three untreated batches as the control group. The phenols effectively retarded the growth of Pseudomonas fluorescens and Enterobacteriaceae, acting mainly on the lag phase of the microorganisms, resulting in the prolongation of the time needed to reach the acceptable microbial limit. The delay in the growth of the spoilage bacteria was considered to indirectly influence the sensorial acceptability threshold, recorded through survival analysis. The combination of the two above-mentioned factors promotes the extension of "Fior di latte" cheese shelf life. by >2 and 4 days, for PA and PB respectively.