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In this study, 327 presumptive lactic acid bacteria (LAB) were isolated from goats' milk acid curds produced at a Sicilian dairy farm with the aim to identify potential starter cultures for traditional cheeses. All isolates were first processed by randomly amplified polymorphic DNA (RAPD)-PCR analysis. This approach identified 63 distinct strains which were evaluated for their acidifying capacity. Only 15 strains specifically stood out for their acidification capacity and were identified through 16S rRNA gene sequencing as Lactococcus lactis (11 strains) Enterococcus faecalis (three strains), and Ligilactobacillus animalis (one strain). Notably, all 15 LAB isolates produced bacteriocin-like inhibitory substances and anti-biofilm compounds, against both planktonic and biofilm forms of Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli, and Staphylococcus aureus, albeit at varying levels. Among these 15 LAB, En. faecalis RGM25 and Lc. lactis RGM55, susceptible to five antibiotics tested, were put in contact with wooden vat prototypes, because all equipment used in traditional cheese production in Sicily are made of wood. Scanning electron microscopy and bacterial plate counts of the wooden vat prototypes showed the development of biofilms at levels of approximately 6.0 log CFU/cm 2 . Overall, this study contributes to establishing a custom-made LAB starter cultures with bio-preservatives properties for Sicilian cheese productions., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest for this research., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Mead is a beverage produced by alcoholic fermentation of honey-must. The starter yeasts that are commonly used for the alcoholic fermentation of honey-must are oenological Saccharomyces cerevisiae strains. The objective of the present work was, for the first time, to apply yeasts of honey by-products origin to evaluate the influences the taste-olfactory attributes of mead. For this purpose, three experimental productions were set up, which included: (i) single inoculation of S. cerevisiae; (ii) single inoculation of Hanseniaspora uvarum; (iii) sequential inoculation of H. uvarum/S. cerevisiae. Two control trials were performed, using a commercial strain of S. cerevisiae of oenological origin and a spontaneous fermentation. The results of the chemical parameters showed differences between the trials in terms of residual sugars, acetic acid, glycerol, ethanol and volatile organic compounds. Sensorial analysis also showed a high heterogeneity among trials. The attributes of sweetness, honey and floral were found in mead fermented with H. uvarum, whereas all meads obtained with S. cerevisiae were dry, balanced and without off-odors and off-flavours. The results obtained showed that the controlled application of conventional and non-conventional yeast strains isolated from honey by-products origin could be a promising approach to improve the quality of meads., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Catarratto is one of the most common non-aromatic white grape varieties cultivated in Sicily (Southern Italy). In order to improve the aromatic expression of Catarratto wines a trial was undertaken to investigate the effect of yeast strain, nutrition and reduced glutathione. Variables included two Saccharomyces cerevisiae strains, an oenological strain (GR1) and one isolated from honey by-products (SPF52), three different nutrition regimes (Stimula Sauvignon Blanc™ (SS), Stimula Chardonnay™ (SC) and classic nutrition practice), and a specific inactivated yeast rich in reduced glutathione to prevent oxidative processes [Glutastar™ (GIY)] ensuing in ten treatments (T1-T10). Microbiological and chemical parameters demonstrated the aptitude of strain SPF52 to successfully conduct alcoholic fermentation. During fermentation, the Saccharomyces yeast populations ranged from 7 to 8 logarithmic CFU/mL. All wines had a final ethanol content ranging between 12.91 and 13.85% (v/v). The dominance of the two starter strains over native yeast populations was higher than 97% as estimated by interdelta analysis. The addition of nutrients SS or SC increased the aromatic complexity of the wines as reflected by volatile organic compounds (VOCs) composition and sensory profiles. In particular, 32 VOCs were identified; alcohols (62.46-81.1%), thiols (0.27-0.87%), ethers (0.09-0.16%), aldehydes (0-1.21%), ketones (0-2.28%), carboxylic acids (4.21-12.32%), esters (0-10.85%), lactones (0.9-1.49%) and other compounds (0.77-6.9%). Sensory analysis demonstrated a significant impact on wine aroma in relation to yeast starter strain used, the type of nutrition (SS, SC or classic nutrition) and the presence/absence of GIY. The wines produced with GR1 yeast strain and SS (T2), SPF52 with SC (T9) both in presence of GIY showed higher overall quality. Trials T2 and T9 showed the highest scores for 13 and 18 attributes, respectively. The different nutrition, addition of GIY and the yeast starter strains diversified and enhanced sensory expression of Catarratto wines., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The 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/cm 2 . In some cases, LAB were counted at very high levels (8.2 log CFU/cm 2 ). 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 . IMPORTANCE This study provides evidence for the lack of pathogenic bacteria on the wooden shelves used to ripen internal bacterially ripened semihard and hard cheeses produced in Sicily. These three cheeses are not inoculated on their surfaces, and surface ripening is not considered to occur or, at least, does not occur at the same extent as surface-inoculated smear cheeses. Several bacterial groups identified from the wooden shelves are typically associated with smear cheeses, strongly suggesting that PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano cheese rind contributes to their final organoleptic profiles.

This review article focuses on the technological aspects and microbiological critical points of pressed-cooked cheeses processed from raw ewe's milk without the inoculation of starter cultures, in particular "Pecorino" cheese typology produced in Italy. After showing the composition of the biofilms adhering to the surface of the traditional dairy equipment (mainly wooden vat used to collect milk) and the microbiological characteristics of PDO Pecorino Siciliano cheese manufactured throughout Sicily, this cheese is taken as a case study to develop a strategy to improve its hygienic and safety characteristics. Basically, the natural lactic acid bacterial populations of fresh and ripened cheeses were characterized to select an autochthonous starter and non-starter cultures to stabilize the microbial community of PDO Pecorino Siciliano cheese. These bacteria were applied at a small scale level to prove their in situ efficacy, and finally introduced within the consortium for protection and promotion of this cheese to disseminate their performances to all dairy factories. The innovation in PDO Pecorino Siciliano cheese production was proven to be respectful of the traditional protocol, the final cheeses preserved their typicality, and the general cheese safety was improved. An overview of the future research prospects is also reported.

The present study was carried out to produce Protected Denomination of Origin (PDO) Pecorino Siciliano cheese with a multi-species lactic acid bacteria (LAB) culture, composed of starter and non-starter strains in order to reduce the microbiological variability of the products derived without LAB inoculums. To this end, cheese samples produced in six factories located in five provinces (Agrigento, Catania, Enna, Palermo and Trapani) of Sicily, and previously characterised for physicochemical, microbiological and sensory aspects, have been investigated in this work for bacterial microbiome, fatty acid (FA) composition as well as volatile organic compound (VOC) profiles. Analysis of the cheese microbiomes indicated that streptococci (30.62-77.18% relative abundance) and lactobacilli (on average 25.90% relative abundance) dominated the bacterial communities of control cheeses, produced without exogenous inoculums, whereas the cheeses produced with the selected multi-strain culture saw the dominance of lactococci (in the range 6.49-14.92% relative abundance), streptococci and lactobacilli. After the addition of the selected mixed culture, Shannon index increased in all cheeses, but only the cheeses produced with the selected LAB mixed culture in the factory 2 showed Gini-Simpson diversity index (0.79) closer to the reference value (0.94) for a perfect even community. FA composition, mainly represented by saturated FA (on average 69.60% and 69.39% in control cheeses and experimental cheeses, respectively), was not affected by adding LAB culture. The presence of polyunsaturated FA ranged between 7.93 and 8.03% of FA. VOC profiles were different only for the content of butanoic acid, registered for the experimental cheeses at higher concentrations (on average 662.54 mg/kg) than control cheeses (barely 11.96 mg/kg). This study validated addition of the ad hoc starter/non-starter culture for PDO Pecorino cheese production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)