In-depth investigation of the safety of wooden shelves used for traditional cheese ripening

9openInternationalItalian coauthor/editorThe main goal of this research was to characterize the bacterial diversity of the wooden boards used for aging traditional Sicilian cheeses and to evaluate whether pathogenic bacteria are associated with these surfaces. Eighteen cheese dairy factories producing three traditional cheese typologies (PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano) were selected within the region of Sicily. The wooden shelf surfaces were sampled by a destructive method to detach wood splinters as well as by a nondestructive brushing to collect microbial cells. Scanning electron microscopy showed the presence of almost continuous bacterial formations on the majority of the shelves analyzed. Yeasts and fungal hyphae were also visualized, indicating the complexity of the plank communities. The amplicon library of the 16S rRNA gene V3-V4 region was paired-end sequenced using the Illumina MiSeq system, allowing the identification of 14 phyla, 32 classes, 52 orders, 93 families, and 137 genera. Staphylococcus equorum was identified from all wooden surfaces, with a maximum abundance of 64.75%. Among cheese-surface-ripening bacteria, Brevibacterium and Corynebacterium were detected in almost all samples. Several halophilic (Halomonas, Tetragenococcus halophilus, Chromohalobacter, Salimicrobium, Marinococcus, Salegentibacter, Haererehalobacter, Marinobacter, and Idiomarinaceae) and moderately halophilic (Salinicoccus, Psychrobacter, and Salinisphaera) bacteria were frequently identified. Lactic acid bacteria (LAB) were present at low percentages in the genera Leuconostoc, Lactococcus, Lactobacillus, Pediococcus, and Streptococcus. The levels of viable microorganisms on the wooden shelves ranged between 2.4 and 7.8 log CFU/cm2. In some cases, LAB were counted at very high levels (8.2 log CFU/cm2). Members of the Enterobacteriaceae family were detected in a viable state for only six samples. Coagulase-positive staphylococci, Salmonella spp., and Listeria monocytogenes were not detected. Seventy-five strains belonged to the genera Leuconostoc, Lactococcus, Pediococcus, Enterococcus, Lactobacillus, and Weissella.openSettanni, Luca; Busetta, Gabriele; Puccio, Valeria; Licitra, Giuseppe; Franciosi, Elena; Botta, Luigi; Di Gerlando, Rosalia; Todaro, Massimo; Gaglio, RaimondoSettanni, L.; Busetta, G.; Puccio, V.; Licitra, G.; Franciosi, E.; Botta, L.; Di Gerlando, R.; Todaro, M.; Gaglio, R

The wooden shelf surface and cheese rind mutually exchange microbiota during the traditional ripening process

The rind acts as a protective barrier for internally-bacterial ripened cheeses. Unlike surface-inoculated smear cheeses, centripetal maturation is not assumed to occur in these cheeses. This research was aimed to evaluate the microbial diversity of the wooden shelves used for the ripening of Protected Denomination of Origin (PDO) Pecorino di Filiano and Protected Geographical Indication (PGI) Canestrato di Moliterno cheeses. The microorganisms associated with the rind of these cheeses were also investigated. Both wooden shelf surfaces and cheese rinds were sampled by brushing method to collect their biofilms. Wooden shelves showed levels of total mesophilic microorganisms (TMM) between 5.6 and 7.2 log CFU/cm2, while cheese rinds between 6.1 and 7.8 log CFU/cm2. The major dairy pathogens (Salmonella spp., Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus) were never detected, while mesophilic and thermophilic bacteria dominated the surfaces of all wooden shelves and cheese rinds. LAB community was represented by Enterococcus spp., Leuconostoc spp., and Marinilactibacillus spp. Among yeasts, Debaryomyces spp., Candida spp., were identified, while Aspergillus spp., and Penicillium spp., dominated the community of filamentous fungi. MiSeq Illumina analysis identified 15 phyla, 13 classes, 28 orders, 54 families, and 56 genera among bacteria. Staphylococcus spp. was identified from all wooden surfaces, with a maximum abundance of 71 %. Brevibacterium, Corynebacterium and halophilic bacteria were detected in almost all samples. Regarding fungi, wooden shelves mainly hosted Aspergillus, Penicillium and Debaryomyces hansenii, while cheese rinds especially Penicillium and D. hansenii. Alpha diversity confirmed a strict correlation between the microbiota of wooden shelves and that of cheese rinds for the majority of factories. This study confirmed that the wooden shelves used for cheese ripening are microbiologically active and represent safe systems. Furthermore, the results of this work clarified the transfer flow between wooden shelves and PDO Pecorino di Filiano and PGI Canestrato di Moliterno cheese surfaces: smear-active microorganisms are mainly transferred from wooden shelves to cheese rind, which potentially contribute to the development of the final organoleptic characteristics; meanwhile, cheeses transfer LAB that are potentially involved in defining the safety aspects of the shelve

Polyphasic characterization of microbiota of “Mastredda”, a traditional wooden tool used during the production of PDO Provola dei Nebrodi cheese

11openInternationalItalian coauthor/editorThe biofilms of the wooden tables used for the acidification of the curd were investigated for PDO Provola dei Nebrodi cheese, a traditional stretched cheese made in eastern Sicily (southern Italy) from raw cows’ milk. To this purpose the wooden tables of four dairy facilities were analysed for their microbiota by scanning electron microscopy (SEM) analysis and a combined culture-independent and -dependent microbiological approach. SEM inspection showed an almost continuous biofilm formation. MiSeq Illumina analysis identified 8 phyla, 16 classes, 25 orders, 47 families and 50 genera. Corynebacterium, Bifidobacterium and lactic acid bacteria (LAB) were detected in all samples. In particular, the LAB genera detected on all wooden tables were Lactobacillus, Streptococcus and Lactococcus. LAB dominated the surfaces of all wooden tables with levels higher than 7.0 Log CFU/cm2. In particular, the LAB found at the highest levels were mesophilic cocci. Coagulase positive staphylococci, Salmonella spp., Listeria monocytogenes and Shiga-toxigenic Escherichia coli were never detected. Twenty-seven dominating LAB strains were identified within the genera Enterococcus, Lactobacillus, Lacticaseibacillus, Lactiplantibacillus, Levilactobacillus, Lactococcus, Leuconostoc, Pediococcus and Streptococcus. This work showed that the wooden table used during the production of PDO Provola dei Nebrodi cheese is a safe system and a microbiologically active toolopenBusetta, Gabriele; Garofalo, Giuliana; Mangione, Guido; Botta, Luigi; Franciosi, Elena; Di Gerlando, Rosalia; Todaro, Massimo; Licitra, Giuseppe; Scatassa, Maria Luisa; Gaglio, Raimondo; Settanni, LucaBusetta, G.; Garofalo, G.; Mangione, G.; Botta, L.; Franciosi, E.; Di Gerlando, R.; Todaro, M.; Licitra, G.; Scatassa, M.L.; Gaglio, R.; Settanni, L

Reduction of PDO Pecorino Siciliano cheese making duration: microbial dynamics and quality attributes deriving from replacing whey permeate with hot water during cooking

This work was carried out with the aim to reduce the transformation duration of Protected Designation of Origin (PDO) Pecorino Siciliano cheese. To this purpose, the cooking in hot water (experimental production, EXP) was compared to the traditional cheese cooking under whey permeate (control production, CTR). The microbiological composition of under rind (UR) and core (Co) section of CTR and EXP cheeses was determined by a combined culture-dependent and -independent approach. Total mesophilic microorganisms and lactic acid bacteria (LAB) present in raw ewes' milk (5.0 log CFU/mL) increased during cheese making and reached values of about 8.0 log CFU/g in both sections (UR and Co) of 5-month ripened cheeses of both productions (CTR and EXP) monitored. The identification of the viable LAB populations in ripened cheeses showed that Enterococcus, Lacticaseibacillus, Lactiplantibacillus, Levilactobacillus, Limosilactobacillus and Streptococcus dominated UR and Co sections of all cheeses. MiSeq Illumina analysis demonstrated that LAB populations (lactobacilli, lactococci and streptococci) dominated the bacterial community of cheeses at 95.63-98.41 % of relative abundance. The two different cooking operations did not influence the physicochemical characteristics of PDO Pecorino Siciliano cheeses. Sensory evaluation performed by artificial senses analysis and trained panelists confirmed that the modification of PDO Pecorino Siciliano cheese production protocol did not significantly affect product characteristics and overall acceptance. Thus, data of this work confirmed that cooking under hot water allowed to reduce transformation duration and safeguard typicality of PDO Pecorino Siciliano cheese

"Aging", sessualità e cinema nella cultura italiana del secondo dopoguerra

Special issue on "aging" and sexuality in the Italian culture

Anti-Listeria activity of citrus essential oils in a fresh ovine cheese

The aim of this study was to evaluate the anti-Listeria activity of essential oils (EOs) extracted from the peel of lemons, oranges and tangerines in a fresh cheese produced with pasteurized ewe’s milk. Four cheesemaking trials were performed at the pilot plant scale level, including one control production without the addition of EOs and three experimental productions obtained by the addition of 200 μL/L of each EOs to milk. Before the addition of EOs, the milk of all trials was inoculated with 107 CFU/mL of the starter cultures (Lactococcus lactis NT1 and NT5) and 104 CFU/mL of pathogenic bacteria (Listeria monocytogenes ATCC19114). Plate counts confirmed the dominance of the starter cultures and a significantly reduction of L. monocytogenes in experimental cheeses. This work indicated that the addition of citrus EOs to milk represents an effective natural alternative to synthetic substances to enhance the microbial safety of this fresh cheese

Effect of red wine soaking on the microbiological profile, total phenolic content and sensory aspects of an ovine pressed cheese

The aim of this study was to produce an ovine pressed cheese with high polyphenol content. To this purpose, fresh Primosale Pecorino cheese was soaked for seven days in Nero d’Avola wine (NDW) and was indicated as experimental cheese production (EP). The final cheese was characterized for its microbiological, chemical and sensory characteristics. Specifically, cheese making was performed with pasteurized ewes’ milk and a commercial starter culture. Control cheese production (CP) did not include the soaking phase in NDW. Plate counts confirmed the dominance of the commercial starter until 109 CFU/g in both CP and EP cheeses. The soaking in NDW increased cheese total phenolic compounds (TPC) of 0.36 g GAE/kg. Sensory evaluation indicated that EP cheese was mostly appreciated by the panelists. This work indicated that soaking in NDW represents a promising strategy to produce a fresh ovine cheese with a high TPC content well appreciated by consumers

Aloe-Based Edible Coating to Maintain Quality of Fresh-Cut Italian Pears (<i>Pyrus communis</i> L.) during Cold Storage

Pear fruits are known for their antioxidant and nutritional characteristics. However, they are very susceptible to rapid decay. Edible coating (EC) represents a good strategy to maintain postharvest quality. The effects of two EC in slowing down the senescence processes in fresh-cut ‘Coscia’ pears were investigated: EC1 (A. vera gel, hydroxypropyl-methylcellulose and pomegranate seeds oil (PSO), EC2 (A. vera gel and hydroxypropyl-methylcellulose). Weight loss, firmness and colour decrease more slowly in both EC-treated than in untreated (CTR) slices; soluble solid content increases faster in CTR, indicating a faster ripening process. The specific investigation of undesired microorganisms did not generate any colony in all analysed samples. Sensory analysis confirmed that the tasters preferred the EC2-treated samples, as they were the only ones that did not show undesirable flavours until the last day of storage