MICROBIAL-FLORA IN HARD AND SOFT CHEESES PACKAGED IN FLEXIBLE PLASTICFILMS

Microbial flora on Port Salut Argentino cheese (soft type) and on Regg ianito Argentino cheese (hard type) was analyzed during ripening in fl exible plastic films with controlled gaseous permeabilities. Reggianit o cheese forms were ripened both by the traditional method and by vacu um-packing in plastic film after initial pre-packing periods of 30 (E3 0) and 45 (E45) days. Lactic acid bacteria, microorganisms growing in MRS, Lee and M17 agar, Enterobacteriaceae, moulds and yeasts, Staphylo coccus aureus, and sulfite-reducing Clostridium were analyzed. In Port Salut cheese Streptococcus spp. predominated over Lactobacillus spp. during the ripening period. In Reggianito cheese, the lactic acid bact eria level which was about 10(7) CFU/g initially, decreased during che ese ripening and reached values close to 10(4) CFU/g or lower. Statist ical analysis showed no significant differences between E30, E45 and n on-packed (Traditional ripened) cheeses with regard to microorganisms growing in M17, Lee and MRS agar.