Microbiological characteristics of Parmigiano Reggiano cheese during the cheesemaking and the first months of the ripening

Abstract

-The aim of this work was to gain a comprehensive view of the microbiological characteristics of milk, natural whey starter, and cheese during the first months of ageing of Parmigiano Reggiano. A significant presence of different microbial groups in raw milk from the initial moments of production was rapidly substituted by various lactic acid bacteria. Natural whey starter contained a large number of thermophilic lactic acid bacteria (Lactobacillus helveticus, L. delbrueckii ssp. lactis, L. delbrueckii ssp. bulgaricus) and some facultatively heterofermentative lactic acid bacteria belonging to L. rhamnosus. Thermophilic lactic acid bacteria disappeared within 30 d. Rod-shaped mesophilic facultatively heterofermentative lactic acid microflora, consisting of L. casei, L. paracasei ssp. paracasei, L. paracasei ssp. tolerans, L. rhamnosus and pediococci, progressively increased up to the fifth month of ageing. Results showed that thermophilic lactobacilli were derived from natural whey starter whereas Streptococcus thermophilus originated from raw milk. Further, natural whey starter was the source of L. rhamnosus which was present throughout the entire period of the cheese ageing. The other components of non-starter lactic acid microflora derived from raw milk.

Antibiotic susceptibility of Lactobacillus rhamnosus strains isolated from Parmigiano Reggiano cheese

“…The findings of strains isolated from the same sample of Parmigiano Reggiano cheese with very dissimilar profiles of RAPD-PCR bands testify the importance of the use of natural whey starter in this type of cheese as a source of a strong biodiversity [16]. On the other hand, the similarity in the profiles of RAPD-PCR bands for strains isolated from different samples of Parmigiano Reggiano cheese evidenced the influence of the raw milk, obtained from pastures of the same, defined geographic area, used in the manufacture of this kind of cheese.…”

“…A total of 63 strains of Lactobacillus rhamnosus, isolated from different samples of Parmigiano Reggiano cheese (from 4 different dairy plants located in various areas of production) at the end of the ripening (24 months) [15,16,32], were used in the present study (Tab. I).…”

“…Within the context of a large-scale research project aimed at isolating and characterising lactic acid bacteria in food, this study examined the antibiotic resistance of Lactobacillus rhamnosus strains of potentially probiotic interest isolated from Parmigiano Reggiano cheese, a hard cooked Italian cheese produced with partly skimmed raw cow milk to which natural whey starter is added and which is then ripened for 12-24 months [15,16,32].…”

Article

“…This approach was first applied to mesophilic lactobacilli isolated from one culture medium and from two commercial Comté cheeses, manufactured at the same time in two different factories but ripened under the same conditions [3]. In the present study the same approach was extended to LAB isolated from four culture media usually used to track a wide range of starter and non-starter LAB in different cooked and ripened cheese varieties [7,15,16,19,22] and was applied to LAB isolated from two other commercial Comté cheeses manufactured 18 months later than the cheeses studied in [3]. The cheeses originated from two different factories, one of them being the same as in the former study, chaque fromage.…”

“…In this type of cheese the internal part represents the major part and the microflora of this group of cheese have been described during cheese-making and/or ripening in various varieties [5,7,15,22]. Lactic acid bacteria and propionibacteria were the two major groups of microflora detected in Comté cheese [16].…”