AIMS: To study the evolution of rind microbial communities in Fontina PDO cheese. METHODS AND RESULTS: Four batches were examined for their surface microflora during ripening, carried out in two different maturing caves, at Ollomont and Pré-Saint-Didier, Aosta Valley region, Northwest of Italy. Culture-dependent methodologies were combined with culture-independent analysis (PCR-DGGE). Yeasts were found to increase from 10(3) to 10(6) CFU cm(-2) in 28 days, with consequent rise of surface pH, which allowed the growth of salt-tolerant bacteria, in particular coryneforms which reached 10(9) CFU cm(-2) at the end of 3 months. Coagulase-negative cocci and lactic acid bacteria reached 10(7) CFU cm(-2) in the same period. Debaryomyces hansenii and Candida sake were the species more constantly present throughout the whole maturing process. As early as after 1 day since manufacture, Lactococcus lactis subsp. lactis and Streptococcus thermophilus were detected on cheese rinds. Arthrobacter nicotianae, Brevibacterium casei and Corynebacterium glutamicum were found after 7-28 days. CONCLUSIONS: According to cluster analysis of DGGE profiles, the maturing environment seemed to influence the dynamics of microbial groups on Fontina surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: These results represent a first picture of micro-organisms colonizing Fontina PDO rinds. Further studies are in progress to better understand the origin of this surface microflora and to formulate surface starters.
AIMS: To study the evolution of rind microbial communities in Fontina PDO cheese. METHODS AND RESULTS: Four batches were examined for their surface microflora during ripening, carried out in two different maturing caves, at Ollomont and Pré-Saint-Didier, Aosta Valley region, Northwest of Italy. Culture-dependent methodologies were combined with culture-independent analysis (PCR-DGGE). Yeasts were found to increase from 10(3) to 10(6) CFU cm(-2) in 28 days, with consequent rise of surface pH, which allowed the growth of salt-tolerant bacteria, in particular coryneforms which reached 10(9) CFU cm(-2) at the end of 3 months. Coagulase-negative cocci and lactic acid bacteria reached 10(7) CFU cm(-2) in the same period. Debaryomyces hansenii and Candida sake were the species more constantly present throughout the whole maturing process. As early as after 1 day since manufacture, Lactococcus lactis subsp. lactis and Streptococcus thermophilus were detected on cheese rinds. Arthrobacter nicotianae, Brevibacterium casei and Corynebacterium glutamicum were found after 7-28 days. CONCLUSIONS: According to cluster analysis of DGGE profiles, the maturing environment seemed to influence the dynamics of microbial groups on Fontina surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: These results represent a first picture of micro-organisms colonizing Fontina PDO rinds. Further studies are in progress to better understand the origin of this surface microflora and to formulate surface starters.