Variability in chemical and microbiological profiles of long-ripened Caciocavallo cheeses

摘要

Five protected designation of origin (PDO) Caciocavallo Silano and 6 non-PDO Caciocavallo cheeses, ripened for 6 mo and collected in the 5 Italian regions of the PDO area (Apulia, Basilicata, Calabria, Campania, and Molise, Italy), were studied to assess their physico-chemical (pH, acidity, moisture, fat, ash, protein, and free amino acid composition) and microbiological profiles. Analyses evidenced a certain fluctuation of previous parameters among samples regardless of the kind of cheese evaluated (PDO and non-PDO). The PCR-denaturing gradient gel electrophoresis analysis performed on the DNA directly extracted from cheeses gave different results, but a low number of bands was always observed. Only one band, corresponding to the species Streptococcus thermophilus, was detectable in 1 PDO and in 2 non-PDO cheese samples, whose free ami-no acid content was the lowest. Analyses were repeated on experimental Caciocavallo cheeses. Specifically, 2 productions were made, one mimicking the industrial technology (pasteurized milk and selected starter culture) and one the artisanal technology (raw milk and natural whey starter). Results obtained on experimental cheeses at 6 mo of ripening showed that industrial samples had lower amounts of total free amino acids then the artisanal ones (1,188.2 vs. 7,523.67 mg/100 g of dry matter). Moreover, the PCR-denaturing gradient gel electrophoresis analysis evidenced the sole presence of S. thermophilus in the case of the industrial technology. These data sustain the hypothesis that, out of 11 cheeses analyzed previously, 1 PDO Caciocavallo Silano and 2 non-PDO Caciocavallo cheeses were obtained with the industrial technology. These results could be of help in the discrimination of PDO products, taking into account that the PDO production regulation does not allow the milk pasteurization, nor the use of selected starters.