Effect of natamycin-containing coating on the evolution of biochemical and microbiological parameters during the ripening and storage of ovine hard-Gruyère-type cheese

The effect of a coating containing natamycin on the ripening course of the hard-Gruyère-type cheese Graviera Kritis was assessed. A single treatment at an early stage of ripening was carried out; samples from natamycin-treated (NT) and control cheeses (CTR) were then taken throughout a 12 month ripening and storage period. Coating gave a statistically significant reduction in the yeasts and moulds counts in the cheese rind. It did not influence the counts and the evolution of the thermophilic bacteria related to starter or of the propionic acid bacteria, nor did it affect the associated aminopeptidase activities. Gross composition of NT cheeses did not differ significantly from that of the control cheeses; the same was also true for proteolysis. Natamycin in the cheese rind after the removal of coating was lower than 0.1 mg dm−2 at all stages of ripening and no migration to the cheese interior was observed.