A survey of the microbial and chemical composition of seven semi-ripened Provola dei Nebrodi Sicilian cheeses

Abstract

Aims: The microbial and chemical composition of seven different semi‐ripened (45 days) Provola dei Nebrodi Sicilian cheese samples were assessed in order to investigate the diversity of the microbial population in cheese made from different geographical areas throughout Sicily. Methods and Results: The samples, which were obtained from seven different Provola dei Nebrodi manufacturers, were assessed using selective media. Interestingly, concentrations of presumptive lactobacilli represented over 90% of the total microbial population. In total, 105 presumptive Lactobacillus isolates were characterized to determine the relatedness of the isolates between the seven different cheeses. Randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis of the 105 presumptive lactobacilli indicated the presence of 22 distinct isolates. Further investigation of the isolates using pulsed field gel electrophoresis (PFGE) following restriction with the enzyme ApaI revealed the presence of 19 distinct macrorestriction patterns and the presence of between one and four distinct isolates per cheese sample (out of a total of 15 isolates per cheese randomly taken from Lactobacillus selective media plates). Analysis of the 16S rDNA sequence of each genetically distinct isolate demonstrated the dominance of the Lactobacillus casei species in all cheese samples assessed. Lactobacillus delbrueckii and Pediococcus pentosaceus species were also detected. The concentration of free amino acids, used to estimate the extent of proteolysis in each cheese, ranged from 59 to 433 mg 100 g−1 cheese. Conclusions: Microbiological assessment of the cheeses demonstrated the dominance of Lactobacillus species after 45 days of ripening with levels ranging from 8·3 to 9·4 log CFU g−1. Significance and Impact of the Study: This study provides new information on the diversity of lactobacilli within an artisanal Sicilian cheese, enabling the identification of 17 strains of Lact. casei, one strain of Lact. delbrueckii and Ped. pentosaceus through the combined use of RAPD PCR, PFGE and 16S rDNA sequencing.

Recent developments in cheese cultures with protective and probiotic functionalities

“…Recently developed molecular tools such as pulsed field gel electrophoresis (PFGE), which is a culturedependent method, temporal temperature gel electrophoresis (TTGE), denaturing gradient gel electrophoresis (DGGE), single strand conformation polymorphism (SSCP), and terminal restriction fragment length polymorphism-(TRFLP-) or length heterogeneity-(LH-) PCR have been successfully used to explore diversity and dynamics of cheese microflora [30,35,49,80,103,113,114]. Throughout cheese manufacturing and ripening, the development of the microflora is influenced by negative interactions between the different microbial populations, such as competition for nutrients, as well as stimulating interactions, such as pH increase and production of growth factors [96].…”

Effect of adjuncts on microbiological and chemical properties of Scamorza cheese

“…Although some cheeses have a protected designation of origin (e.g., fresh cheeses such as Mozzarella di Bufala Campana, and semi-hard or hard cheeses such as Provolone Valpadana, Caciocavallo Silano, Provolone del Monaco, Ragusano; http://ec.europa.eu/ agriculture/quality/door/list.html) according to standards of identity that require the use of raw milk and natural starter cultures or no added starter (Randazzo et al, 2002;Piraino et al, 2005;Aponte et al, 2008;Ercolini et al, 2008;De Angelis and Gobbetti, 2011;De Filippis et al, 2014), several others, including several fresh, semi-hard, and hard varieties, are produced using either direct acid addition or defined starter cultures composed of Streptococcus thermophilus alone or in combination with thermophilic lactobacilli (De Angelis and Gobbetti, 2011). Scamorza and Provola are 2 shortripened varieties that have evolved from traditional cheeses produced throughout southern Italy Cronin et al, 2007); they are similar in texture to low-moisture Mozzarella cheese (Kindstedt, 2004;Kindstedt et al, 2004) and are used as table cheese or pizza topping. Due to their short ripening time (<30 d), these cheeses cannot undergo significant proteolysis compared with cheeses with longer ripening times (such as Caciocavallo and Provolone; Gobbetti et al, 2002;Piraino et al, 2005).…”

Nutritional and therapeutic value of fermented caprine milk

“…Some of the semi‐ripened Sicilian cheeses from goats also must to be mentioned. One of these is Provola dei Nebrodi, with a predominance of the probiotic strain L. casei in its composition (Cronin et al. 2007).…”