Growth and Biocontrol of in Greek Anthotyros Whey Cheese without or with a Crude Enterocin A-B-P Extract: Interactive Effects of the Native Spoilage Microbiota during Vacuum-Packed Storage at 4 °C.

Effective biopreservation measures are needed to control the growth of postprocess contamination in fresh whey cheeses stored under refrigeration. This study assessed growth and biocontrol of inoculated (3 log CFU/g) in vacuum-packed, fresh (1-day-old) or 'aged' (15-day-old) Anthotyros whey cheeses, without or with 5% of a crude enterocin A-B-P extract (CEntE), during storage at 4 °C. Regardless of CEntE addition, the pathogen increased by an average of 2.0 log CFU/g in fresh cheeses on day 15. Gram-negative spoilage bacteria also increased by an average of 2.5 log CFU/g. However, from day 15 to the sell-by date (days 35-40), growth ceased, and progressively, the populations of the pathogen declined in most cheeses. This was due to an unmonitored, batch-dependent natural acidification by spoilage lactic acid bacteria, predominantly , which reduced the cheese pH to 5.5, and finally to ≤5.0. The pH reductions and associated declines in pathogen viability were greater in the CEntE-treated samples within each batch. failed to grow in cheeses previously 'aged' in retail for 15 days. Overall, high population levels (>7.5 log CFU/g) of psychrotrophic , particularly , were associated with an extended growth and increased survival of during storage.