Impact of Nisin and Nisin-Producing ssp. on and Bacterial Ecosystem of Cheese Matrices.

spores survive milk pasteurization and cause late blowing of cheeses and significant economic loss. The effectiveness of nisin-producing ssp. 32 as a protective strain for control the growth in Cheddar cheese slurry was compared to that of encapsulated nisin-A. The encapsulated nisin was more effective, with 1.0 log reductions of viable spores after one week at 30 °C and 4 °C. Spores were not detected for three weeks at 4 °C in cheese slurry made with 1.3% salt, or during week 2 with 2% salt. Gas production was observed after one week at 30 °C only in the control slurry made with 1.3% salt. In slurry made with the protective strain, the reduction in count was 0.6 log in the second week at 4 °C with both salt concentration. At 4 °C, nisin production started in week 2 and reached 97 µg/g after four weeks. Metabarcoding analysis targeting the sequencing of 16S rRNA revealed that the genus dominated for four weeks at 4 °C. In cheese slurry made with 2% salt, the relative abundance of the genus decreased significantly in the presence of nisin or the protective strain. The results indicated that both strategies are able to control the growth of development in Cheddar cheese slurries.