Listeria monocytogenes is an important foodborne pathogen, markedly persistent even in harsh environments and responsible for high hospitalization and mortality rates. The aim of the present study was to detect the strains circulating in Sicily over a five-year period and characterize their antimicrobial resistance profiles. The key element of this study was the sharing of data among various entities involved in food control and clinical surveillance of listeriosis in order to develop an integrated approach for this pathogen. A total of 128 isolates were analyzed, including 87 food-source strains and 41 clinical specimens. Whole-genome sequencing (WGS) was performed for sequence type (ST) and clonal complex (CC) identification through multilocus sequence typing (MLST) analysis. Antimicrobial resistance was assessed using the Kirby–Bauer method. The majority of strains belonged to serotype IVb (34/41 and 53/87 of clinical and food-source isolates, respectively) and were subtyped as CC2-ST2 (28/34 and 41/53 of clinical and food-source isolates respectively). Most of the isolates were susceptible to the main antimicrobials recommended for treatment of listeriosis. Resistance (R) and intermediate resistance (I) percentages worthy of attention were found against oxacillin (R: 85.9%) and clindamycin (I: 34.6%) in the food-source isolates and trimethoprim/sulfamethoxazole (R: 29.23%) in the clinical isolates. Also, 7.7% of the food-source isolates were multidrug resistant. Our results highlight how the punctual comparison between food and clinical strains is an essential tool for effectively tracking and preventing foodborne outbreaks.

Antimicrobial resistance (AMR) poses a growing threat to global health, and its spread through the food chain is gaining increasing attention. While AMR in food of animal origin has been extensively studied, less is known about its prevalence in plant-based foods, particularly fresh and ready-to-eat (RTE) vegetables. This study investigated the occurrence of antimicrobial-resistant bacteria in fresh and RTE vegetables. Isolates were subjected to antimicrobial susceptibility testing and molecular analyses for the characterization of antimicrobial resistance genes (ARGs). A significant proportion of samples were found to harbor antimicrobial-resistant bacteria, including multidrug-resistant strains. Several ARGs, including those encoding extended-spectrum β-lactamases (ESBLs) and resistance to critically important antimicrobials, were detected. The findings point to environmental contamination—potentially originating from wastewater reuse and agricultural practices—as a likely contributor to AMR dissemination in vegetables. The presence of antimicrobial-resistant bacteria and ARGs in fresh produce raises concerns about food safety and public health. The current regulatory framework lacks specific criteria for monitoring AMR in vegetables, highlighting the urgent need for surveillance programs and risk mitigation strategies. This study contributes to a better understanding of AMR in the plant-based food sector and supports the implementation of a One Health approach to address this issue.

Foodborne diseases result from the consumption of foods contaminated with pathogens or their toxins and represent a serious public health problem worldwide. This study aimed to assess the presence of Rotavirus (RoV), Adenovirus (AdV), Norovirus (NoV), Hepatitis A and Hepatitis E viruses (HAV and HEV, respectively), Toxoplasma gondii, Coxiella burnetii and Leptospira spp. across various food matrices in Sicily. The analysis concerned 504 samples, including mussels, farmed meat, game meat, vegetables and bulk milk. Following appropriate pre-treatment, acid nucleic extraction was carried out and amplification of pathogen nucleic acids was carried out by molecular methods. The mussels tested positive for NoVs (3/51, 5.9%) and farm meat resulted positive for T. gondii (1/34, 2.9%). The game offal samples tested positive for HEV, which was detected in 17 out of 222 samples (7.7%), and T. gondii (18/318, 5.7%) and Leptospira spp. (2/318, 0.6%). The milk samples tested positive for C. burnetii (15/85, 17.6%), T. gondii (2/85, 2.4%) and Leptospira spp. (1/85, 1.2%). This study highlights the variability in the risk of contamination of different food matrices, confirming the importance of vigilance in the consumption of potentially contaminated food products.

Italy is the third largest producer of Opuntia fruits in the world after Mexico and the United States, and 97.72% of these fruits produced by Italy are grown in Sicily. The use of prickly pear fruits or juice leads to a high production of by-products. In this study, ensiling was chosen to preserve prickly pear peels (PPPs) and “pastazzo” (PPS) mixed with 12% wheat bran. PPP silage presented a lower DM than PPS silage (20.03 vs. 41.37%; p < 0.01), as well as aNDFom (25.31 vs. 66.66% DM; p < 0.01), but had the best protein content (12.02 vs. 9.55% DM; p < 0.01). For both by-products, fermentation proceeded rapidly with increasing temperature, with the temperature for PPS (38 °C) being higher than that for the PPP (30 °C). Mesophilic LAB (lactic acid bacteria) were detected at higher levels than thermophilic LAB, and rod counts were higher than cocci counts. The detected organic acids and silage pH indicate an optimal fermentation process for these by-products. PPP silage had a higher polyphenol content than PPS silage (30.24 vs. 24.22 mg GAE/g DM; p < 0.01) and, consequently, also higher antioxidant activity. The results of this study on the mineral composition and macro- and micro-nutrients in silage highlight that these by-products are sources of minerals, with high levels of potassium, calcium, and magnesium.

Notification of foodborne outbreaks has been mandatory in Europe since 2005, and surveillance is carried out along the entire food chain. Here we report the results obtained from laboratory investigations about four cases of foodborne outbreaks that occurred in Sicily between 2009 and 2016, deemed to be related to staphylococcal enterotoxins (SEs) and coagulase-positive Staphylococci (CPS) by the Local Public Health Authority. Primosale cheese samples were processed by culture methods for enumeration of CPS and immunoenzymatic assays for detection and differentiation of the SEs possibly contained in food samples. In all cases, the mistrusted foods were found to be contaminated by CPS at bacterial loads between 5 and 8 log CFU/g and contained SE type C (SEC). The reported data confirm the risk of staphylococcal food poisoning associated with the consumption of raw milk cheese. The SEC is the most commonly occurring SE in goat milk and dairy products and the most represented enterotoxin in Sicilian dairy products. Our results highlighted the need for improving the current monitoring efficiency and implementing the available laboratory methods to collect more faithful epidemiological data on the current prevalence of staphylococcal toxins in the food chain, including SEs currently not detectable by validated analytical methods.

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.

Antioxidants are the most popular active ingredients in anti-aging cosmetics as they can restore the physiological radical balance and counteract the photoaging process. Instead of adding pure compounds into the formulations, some “precious” vegetable oils could be used due to their content of tocopherols, phenols, vitamins, etc., constituting a powerful antioxidant unsaponifiable fraction. Here, electron paramagnetic resonance (EPR) spectroscopy coupled with spin trapping was proven to provide a valid method for evaluating the antioxidant properties and the oxidative resistance of vegetable oils which, following UV irradiation, produce highly reactive radical species although hardly detectable. Extra virgin olive oil, sweet almond oil, apricot kernel oil, and jojoba oil were then evaluated by using N-t-butyl-α-phenylnitrone as a spin trapper and testing different UV irradiation times followed by incubation for 5 to 180 min at 70 °C. The EPR spectra were manipulated to obtain quantitative information useful for comparing the different tested samples. As a result, the knowledge acquired via the EPR analyses demonstrated jojoba oil as the best of the four considered oils in terms of both starting antioxidant ability and oxidative stability overtime. The obtained results confirmed the usefulness of the EPR spin trapping technique for the main proposed purpose.

Seafood can vehiculate foodborne illnesses from water to humans. Climate changes, increasing water contamination and coastlines anthropization, favor the global spread of Vibrio spp. and the occurrence of antibiotic-resistant isolates. The aim of this study was to evaluate the spread of potentially pathogenic Vibrio spp. in fishery products collected in Sicily and to assess their antibiotic resistance. Bacteriological and molecular methods were applied to 603 seafood samples to detect V. parahaemolyticus, V. cholerae, V. vulnificus, and Vibrio alginolyticus in order to assess their pathogenicity and antimicrobial resistance. About 30% of bivalves and 20% of other fishery products were contaminated by Vibrio spp.; V. parahaemolyticus accounted for 43/165 isolates, 3 of which were carrying either tdh or trh; V. cholerae accounted for 12/165 isolates, all of them non-O1 non-O139 and none carrying virulence genes; and V. vulnificus accounted for 5/165 isolates. The highest rates of resistance were observed for ampicillin, but we also detected strains resistant to antibiotics currently included among the most efficient against Vibrio spp. In spite of their current low incidence, their rise might pose further issues in treating infections; hence, these results stress the need for a continuous monitoring of antimicrobial resistance among fishery products and an effective risk assessment.

The spread of multidrug resistant (MDR) Salmonella strains, along the poultry supply chain, can represent a relevant threat to human health. This study aimed to evaluate the prevalence and antimicrobial resistance of Salmonella spp. isolated from poultry meat for human consumption. Between 2019 and 2021, 145 samples were analyzed according to ISO 6579-1:2017. The strains isolated were identified by using biochemical-enzymatic assays and serotyping, according to the Kauffmann-White-Le Minor scheme. The antibiotic susceptibility tests were determined using the Kirby-Bauer method. Forty Salmonella spp. strains were isolated and serotyping showed Salmonella Infantis to be predominant. 80% of the isolated strains were MDR and identified as S. Infantis. This study confirms the circulation of MDR Salmonella isolated from poultry meat and highlights the predominance of the S. Infantis serovar, which represents an emerging risk factor under the One Health holistic approach.

This preliminary study aimed to detect biological and chemical contaminants in vegetables sold in Sicily for human consumption, assess the spread of antimicrobial-resistant (AMR) strains in these foods, and characterize their antimicrobial-resistance genes. A total of 29 fresh and ready-to-eat samples were analyzed. Microbiological analyses were performed for the detection of Salmonella spp. and the enumeration of Enterococci, Enterobacteriaceae, and Escherichia coli. Antimicrobial resistance was assessed by the Kirby-Bauer method, according to the Clinical and Laboratory Standards Institute guidelines. Pesticides were detected by high-performance liquid chromatography and gas chromatography coupled with mass spectrometry. No samples were contaminated by Salmonella spp., E. coli was detected in 1 sample of fresh lettuce at a low bacterial count (2 log cfu/g). 17.24% of vegetables were contaminated by Enterococci and 65.5% by Enterobacteriaceae (bacterial counts between 1.56 log cfu/g and 5.93 log cfu/g and between 1.6 log cfu/g and 5.48 log cfu/g respectively). From 86.2% of vegetables, 53 AMR strains were isolated, and 10/53 isolates were multidrug resistant. Molecular analysis showed that the blaTEM gene was detected in 12/38 β-lactam-resistant/intermediate-resistant isolates. Genes conferring tetracycline resistance (tetA, tetB, tetC, tetD, tetW) were detected in 7/10 isolates. The qnrS gene was detected in 1/5 quinolone-resistant isolates, the sulI gene was detected in 1/4 sulfonamide- resistant/intermediate-resistant isolates and the sulIII gene was never detected. Pesticides were detected in 27.3% of samples, all of which were leafy vegetables. Despite the satisfactory hygienic status of samples, the high percentage of AMR bacteria detected stresses the need for an effective monitoring of these foods as well as adequate strategies to counteract the spread of AMR bacteria along the agricultural chain. Also, the chemical contamination of vegetables should not be underestimated, especially considering that leafy vegetables are commonly consumed raw and that no official guidelines about maximum residue limits of pesticides in ready-to-eat vegetables are available.

Salmonella spp. are among the most frequent causes of foodborne diseases, and the increasing occurrence of MDR strains is an additional cause for concern. In the three-year period 2019–2021, we collected Salmonella spp. strains isolated from different food categories analysed in the context of Regulation (EC) No 2073/2005 in order to assess their antibiotic susceptibility profiles and ESBL production. To determine the susceptibility profiles and identify MDR strains, we used the Kirby–Bauer method to test 17 antibiotics. Double-disc and PCR testing then allowed us to assess the production of ESBLs and the presence of beta-lactamase resistance genes. Phenotypic tests showed that 36 out of 67 strains were MDR and 52.7% of these were ESBL producers. Finally, molecular investigations conducted on ESBL-producing strains revealed the presence of blaSHV, blaCTX-M and blaTEM genes. Our results confirmed the prevalence of S. Infantis, an MDR strain and ESBL producer, in chicken meat. This suggests that further research on the prevalence of antibiotic resistance genes (ARGs) in foodborne strains is needed, especially from a One Health perspective.

This study shows the frequency of seeds samples contaminated by Salmonella spp. collected randomly from local markets; on 30 black pepper sample no contaminated sample was found while Salmonella spp. was detected in 3 of 36 (8.3%) analyzed sesame samples; three different serotypes were identified: S. Montevideo, S. Stanleyville e S. Tilene. The efficacy of gamma irradiation to inactivate Salmonella Montevideo in black pepper and sesame irradiated between 1 and 5 kGy was evaluated. 3 kGy is sufficient to reduce of 3-4 log CFU/g; whereas 5 kGy have been need to reduce 5.5-6 log CFU/g for samples of black pepper and sesame. No statistically significant differences were found between black pepper and sesame.

Arcobacter spp. are emerging waterborne and foodborne zoonotic pathogens responsible for gastroenteritis in humans. In this work, we evaluated the occurrence and the antimicrobial resistance profile of Arcobacter isolates recovered from different aquatic sources. Besides, we searched for Arcobacter spp. in seaweeds and the corresponding seawater samples. Bacteriological and molecular methods applied to 100 samples led to the isolation of 28 Arcobacter isolates from 27 samples. The highest prevalence was detected in rivers followed by artificial ponds, streams, well waters, and spring waters. Seaweeds contained a higher percentage of Arcobacter than the corresponding seawater samples. The isolates were identified as Arcobacter butzleri (96.4%) and Arcobacter cryaerophilus (3.6%). All the isolates showed a multi-drug resistance profile, being resistant to at least three different classes of antibiotics. Molecular analysis of genetic determinants responsible for tetracycline resistance in nine randomly chosen isolates revealed the presence of tetO and/or tetW. This work confirms the occurrence and the continuous emergence of antibiotic-resistant Arcobacter strains in environmental samples; also, the presence of quinolone-resistant Arcobacter spp. in aquatic sources used for water supply and irrigation represents a potential risk for human health.

In Sicily, the current increasing cultivation of Opuntia ficus-indica corresponds to an availability of prickly pear by-product (PPB) that results from fruit processing for juice extraction. This investigation aims to evaluate the nutritional traits of PPB for ruminant feeding and its stability during a 21-day outdoor storage, using potassium metabisulfite (PMB) as a preservative agent, added to the PPB mass at different doses (0, 50, 100, and 150 g/kg). The fractioning of PPB showed that it included 28% of peel and pulp and 72% of seeds on a dry matter (DM) basis. On the whole, this by-product was low in crude protein (5.32% DM), high in fiber content (51.38%, 41.15% and 14.64% DM for NDFom, ADFom and ADL respectively), non-fiber carbohydrates (NFC, 29.68% DM), and soluble sugars (13.3% DM), with a moderate level of net energy for lactation (4.59 MJ/kg DM). Storage was the main factor of alteration of PPB chemical composition with the exception of ether extract. A decline of NFC and soluble sugars, due to microbial fermentation, was observed with all PMB treatments, especially during the first week of storage, probably due to evolution of both coccus (M17) and rod LAB (MRS), which increased their loads at the seventh day of storage.

This study aimed to verify the applicability of the EN 1787 method for the detection of irradiation in herbal ingredients used in Plant Food Supplements (PFSs). In matrices such as herbs and spices the main limit of the method is the presence of intrinsic radicals responsible for spurious signals leading to complex ESR spectra. To overcome this limit, before ESR measurement a treatment with alcohol has been proposed (Delincee and Soika, 2002; Ahn et al., 2012, 2014). As reported in the literature, this treatment is expected to reduce/eliminate the confounding signals so that the samples may be correctly classified. In this study the efficacy of the pre-treatment was tested on raw herbal ingredients largely used for PFSs, namely Camellia sinensis, Cinnamomum verum, Curcuma longa, Ginkgo biloba, Silybum marianum, Vaccinium myrtillus and Zingiber officinale. Non-irradiated and irradiated (5, 10 kGy) samples were analysed before and after pre-treatment. The results showed a general decrement of signal intensity. In some cases, this was associated with the elimination of some spurious signals, which, however, did not always ensue in an easier interpretation of the ESR spectra. Only for two matrices (Camellia sinensis and Vaccinium myrtillus) was alcoholic extraction crucial for the correct classification of the samples.

This paper reports the results of a study carried out to verify the applicability of the EN 1787 method, which uses the Electron Spin Resonance (ESR) technique for the identification of irradiated plant-origin foods with health benefits. The method was tested on samples of herbal ingredients of Plant Food Supplements (PFSs), nuts and fresh blueberries. Untreated and irradiated samples of Camellia sinensis (leaves) Ginkgo biloba (leaves), Glycine max (seeds), Silybum marianum (fruits), Vaccinium myrtillus (fruits), almonds, hazelnuts, peanuts, pistachios, walnuts and fresh blueberries were analysed. The work includes an inter-laboratory blind test involving five Italian laboratories that perform routine analyses for the official control of irradiated food. A total of 180 untreated and irradiated samples of PFS ingredients, nuts and fresh blueberries were analysed. The analyses on the irradiated samples were replicated even a long time after irradiation (up to two years depending on the matrix) to test the reliability of the method throughout the shelf life of the products. The results were matrix-dependent: all the 5 kGy irradiated nuts and the 1 kGy-irradiated blueberries were correctly classified, whereas herbal ingredients showed complex ESR spectra with spurious signals which often prevented the correct classification of the sample.

Background: Consumption of raw cheese may be associated with different diseases. This study aimed to evaluate behavior of four pathogenic bacteria during manufacture and ripening of Protected Designation of Origin (PDO) Pecorino Siciliano cheese. Methods: The experimental cheese groups were inoculated with pathogenic bacteria, including Escherichia coli O157, Listeria monocytogenes, Salmonella Enteritidis, and Staphylococcus aureus. The cheese making processes were monitored from milk curdling until 3 months ripened cheeses and the levels of Lactic Acid Bacteria (LAB) and the four dairy pathogens were evaluated by plate counts. Randomly Amplified Polymorphic DNA (RAPD)-Polymerase Chain Reaction (PCR) analysis was applied to confirm that the colonies isolated during the several steps of production were the same strains added in milk. Statistical analysis was done using XLStat software. Results: The levels of mesophilic and thermophilic coccus and rod LAB in curd were comparable in both trials and reached values between 8-9 log10 Colony Forming Unit (CFU)/g in cheeses at 90 days of ripening. The four pathogenic bacteria were found in experimental curd at levels higher than those inoculated in milk and completely disappeared after 60 days of ripening. The RAPD analysis clearly demonstrated the presence of the added strain during production and confirmed the results of plate counts. Conclusion: This work showed that the production conditions of PDO Pecorino Siciliano cheese decreased growth of E. coli O157, L. monocytogenes, S. Enteritidis, and S. aureus

The physicochemical characteristics and sensory traits of Cinisara bresaola were investigated, to explore a new commercial opportunity for autochthonous dairy cattle farms. Semimembranosus, Semitendinosus and Biceps brachii muscles, from adult cows (AC) and grazing (GB) or housed (HB) young bulls of Cinisara breed, were processed to made bresaola. Differences due to animal category and muscle type were observed. Bresaola from AC was richer in fat and volatile organic compounds. The bresaola from Semitendinosus showed higher colorimetric parameters, fat and, when from grazing animals, Warner-Bratzler shear force than those made from other muscles. In general, all bresaola were well appreciated. The principal component analysis performed using selected physicochemical and sensory traits was able to discriminate bresaola produced from different animal categories, effect of muscle type was relevant only for AC. These results evidenced the possibility to obtain bresaola from the meat of different animal categories, comparable for sensory properties and appreciable by consumers.