Italian Journal of Food Safety最新文献

L. monocytogenes is a foodborne pathogen responsible for a serious disease with a high mortality rate, particularly in vulnerable consumers. Recently, the scientific community has shown increasing attention to the search for new natural molecules with antimicrobial activity, aimed at preventing the spread of foodborne diseases. Extremophilic microorganisms, typical of extreme temperature environments, are a valuable source of these molecules. The present work aimed to study the antibacterial activity of four pure compounds derived from a molecule, the pentadecanal, produced by the Antarctic bacterium Pseudoalteromonas haloplanktis, against two different pathotypes of L. monocytogenes. Growth assays were performed in 96-well polystyrene plates with serial dilutions of the tested compounds at different concentrations (0.6, 0.3, 0.15, 0.07 mg/mL). The plates were incubated at 37°C for 24 h, with a spectrophotometric reading at OD 600 nm. Preliminary results of this study showed that pentadecanal inhibits the growth of L. monocytogenes, with a MIC (Minimum Inhibitory Concentration) of 0.6 mg/mL. Acetal, carboxylic acid, and ester did not demonstrate antibacterial activity at the concentrations tested. These findings suggest the possibility of using pentadecanal as a natural antibacterial to improve safety standards along the food supply chain.

"Grottone" is a pasta filata hard cheese produced in Campania region from cow's milk and characterized by holes formation due to CO² development by Propionic Acid Bacteria. The contamination of raw milk with butyric acid-producing spore-forming clostridia represent a major concern for cheese producers since clostridia outgrowth may lead to the cheese late blowing defect during ripening. Detection of clostridial endospores in milk before processing and the use of antimicrobial compounds may represent an important control strategy. The present study is aimed to point out the most suitable procedure for the determination of clostridial spores in dairy samples, and to assess the inhibitory activity of several antimicrobial compounds against Cl. sporogenes. Based on results, MPN counts on Bryant and Burkey medium and CFU on RCM proved to be the most suitable protocols for routine testing. By using these procedures clostridial spores were detected in 10 out 13 milk samples and in all cheeses with late blowing defect. Within antimicrobial compounds, sodium nitrate is still the best choice for preventing late blowing, nevertheless a protective culture of Lacticaseibacillus casei proved to be a promising alternative. Nevertheless, the use of this protective culture in six Grottone cheese productions carried out at farm level, led to unsatisfactory results. Holes' development was hampered likely for an inhibition of the PAB starter and the expected 'Grouviera-type' taste was not perceived by panellists. Based on results, the use of protective cultures needs to be contextualized and interactions with starters needs to be evaluated case by case.

The present study aimed at assessing the occurrence of microbiological hazards (Listeria monocytogenes, Staphylococcus aureus, Salmonella spp. and Escherichia coli O157) in an artisanal soft cheese produced in northern Italy. In the same product total bacterial count, lactic acid bacteria and Enterobacteriaceae were enumerated, and pH and water activity measured in two batches sampled in summer and winter. Samples of raw materials, environmental swabs from the production processes and cheese during 15 days of storage at 2 and 8°C as well as dynamic temperature of 2°C for 5 days and 8°C for 10 days were collected and tested. The load of total bacterial count was significantly higher in the winter batch in comparison to the summer one, with a significant increase at the end of the storage period also noticed for lactic acid bacteria. Statistical higher values of pH were registered in raw materials and end of storage in winter batch. S. aureus was confirmed only in the winter batch within samples (n=4) of stored cheese. On plates used for E. coli O157 detection, colonies of Klebsiella pneumoniae and Klebsiella oxytoca were isolated. The results suggest that the highest bacterial population in the winter batch was associated to a higher pH in stored cheese and a higher number of biological hazards identified. Their isolation started in the maturation room suggesting this step as relevant for possible cheese contamination.

The aim of this survey was to examine the prevalence and the antimicrobial resistance (AMR) of Salmonella spp. isolated from swine food chain. A total of 435 samples were collected: 360 from slaughterhouse (150 carcasses, 30 cecal samples, 180 environmental samples) and 75 from Italian traditional pork dry sausages. Thirty-six Salmonella were isolated and identified by Polymerase Chain Reaction (PCR): 13,3% (4/30) in fecal samples, 5,5% (10/180) in environmental samples, 7,3% (11/150) in carcasses, and 14,6% (11/75) in Italian traditional dry sausages. Salmonella serotypes were: S. Typhimurium (44,4%), S. Typhimurium monophasic variant (8,3%), S. Typhi (2,8%), S. Enteritidis (22,2%), S. Rissen (16,6%) and S. Derby (5,5%). Phenotypic and genotypic characterization of AMR Salmonella spp. isolates was executed through automatic system (VITEK 2, bioMèrieux) and PCR assays. Salmonella spp. showed phonotypical and genotypical resistance to at least one or more classes of antibiotic. All Salmonella spp. were resistant to aminoglycoside (amikacin and tobramycin) and gentamicin, 86,1% strains were resistant to tetracycline, 55,5% strains were resistant to ampicillin and piperacillin, 25% strains to trimethoprim, 5,5% strains to chloramphenicol, 2,8% strains to amoxicillin/ clavulanic acid, and nitrofurantoin. Among Salmonella isolates, the most detected AMR genes were catA for chloramphenicol (94,4%), nitrofuran nfsA (77.7%), nfsB (86,1%) and, for fluoroquinolone par C (100%) and gyrA (94,4%). This study reported epidemiological data regarding Salmonella spp. and AMR's circulation in the swine food chain. This phenomenon (AMR) has critical repercussions on the final consumer health; therefore, it represents a crucial One-Health issue.

Although Helicobacter pylori (H. pylori) is one of the most common bacterial pathogens of human, its natural reservoirs are still unclear. There is an increasing number of reports that document the occurrence of H. pylori in various foods. This study aimed at isolation of H. pylori from chicken meat sampled. Two hundred and sixty samples were collected randomly from slaughterhouses and markets in Dhamar Governorate, Yemen. Samples were enriched in Brain-Heart Infusion broth in microaerophilic conditions before inoculating the Camp-Blood agar and EYE agar plates. Results showed that 13.8% of samples were contaminated evidenced by H. pylori growth via traditional culture method on agar media. No significant differences between sample types (thighs and breast muscles) (p=0.353) or the sampling source (p=0.816) were observed. Autumn season was associated with increased occurrence of H. pylori. The source of H. pylori in food is still not identified. Proper cooking and good sanitation practices are highly recommended to avoid the infection. Further studies addressing the potential sources of H. pylori are highly suggested.

Bacteria belonging to the genus Pseudomonas are ubiquitous and characterized by a high adaptation capability to different environmental conditions and wide range of temperatures. They may colonize food, sometimes causing alteration. Quite recently, a blue pigmentation due to Pseudomonas fluorescens has been widely reported in mozzarella cheese. In this report, we describe a blue coloration occurred on rabbit meat stored in the refrigeration cell of a slaughterhouse. The alteration was observed after about 72 hours of storage at 4-6°C. Bacteriological analyses were performed, and a microorganism included in the Pseudomonas fluorescens group was identified. The experimental contamination was planned, using a bacterial suspension with 1×10⁸ UFC/ml load to spread on rabbit carcasses. The blue pigmentation appeared after 24 hours of storage in a cell with the same conditions of temperature. The bacterium was reisolated and identified as responsible for the alteration on meat. These findings highlight the importance of considering the members of the genus Pseudomonas and, more specifically, of the P. fluorescens group when the microbiological quality of food is to be ascertained. In fact, even if these bacteria are not considered a public health problem, their presence should be monitored by food industry operators in self-control plans because they may cause alteration in food. In fact, any altered product should be withdrawn from the market in agreement with Regulation (EC) No 178/2002 of the European Parliament and of the Council.

Hepatitis E virus (HEV) is a zoonotic pathogen, responsible for numerous cases of infection in humans. Transmission occurs through the orofecal route, and ingestion of contaminated foods represents an important risk factor for final consumer's health. Wild animal species, in particular wild boar (Sus scrofa), are the main virus reservoirs; liver is the target organ, from which, through the hematic diffusion, HEV reaches different tissues and organs, as muscular one. The hygienic-sanitary critical issues connected with game meat food chain in general, and particularly wild boar, with special regards to any geographical area where this animal species can be directly in contact with humans, domestic ones (i.e., domestic pig), and other wild reservoirs (i.e., wild ruminants), finds favorable environmental conditions, have induced us to conduce the present scientific investigation. During the hunting season 2019/2020, a total of 156 wild boar livers were collected from provided plucks at slaughterhouse in Ascoli Piceno. Nested RT-PCR was used for the viral RNA detection. Results demonstrated a positivity of 5.12% (8/156), and the circulation in the screened area of genotype 3 subtype c, which is frequently identified in Central Italy. HEV sanitary relevance and the emerging role of any food chains in its transmission impose further detailed studies. The molecular screening of hunted wild boars' livers can provide important information about virus's circulation in wild animal populations in a specific area.

Packaging is considered one of the most interesting technological aspects of food production and is a constantly evolving subject in food production. The type of packaging is important for the quality and safety of the product and for the visual appearance of the product to be immediately evaluated by consumers. The purpose of this study was to investigate the effect of four different types of modified atmosphere packaging (ATM) and vacuum packaging (VP) currently used by a company in central Italy, on the main qualitative characteristics of beef. For these two traditional and two new solutions with reduced environmental impact and compostable were evaluated. For each type of packaging, two different products were analyzed: steaks and hamburgers. The samples, immediately after production, were transported to the laboratory in refrigerated containers. Several parameters (color, pH, water holding capacity, drip loss, and microbiological characteristics) were evaluated at time 0 and after 7 (T7), 14 (T14) and 21 days (T21) of storage in the dark and at refrigeration temperature (+4°C ± 2°C). The results showed that the two types of packaging have very similar effects on the water-retaining capacity of the steaks. More noticeable differences were recorded by the colorimetric analysis: for both steaks and hamburgers, the products packaged in the traditional packaging appeared brighter and redder than those packaged in the new alternatives. The microbiological analysis of the steaks showed higher values in the "new" packaging. The formation of abundant ropy slime was observed in one of the samples in the "new" modified atmosphere package at T21. The results of this study showed that the technological characteristics (in particular, the color) and the microbiological characteristics of the steaks and hamburgers were better in "old" packaging, with a better appearance and a longer shelf life. The results obtained show how the research for eco-sustainable products for packaging must be addressed, taking into account the effect of the materials on the qualitative and hygienic- sanitary characteristics of the meat.

The European Food Safety Authority and European Centre of Disease Prevention and Control antimicrobial resistance report published in 2021 shows increasing levels of antimicrobial resistance in Salmonella against antibiotics of choice for human salmonellosis (s-lactams and fluoroquinolones). The aim of the study was to follow the evolution of resistance against some Critical Important Antimicrobials in Salmonella isolates from fresh pork collected in Emilia-Romagna region, northern Italy, over two decades. Emilia-Romagna region is characterized by production of well-known pork derived products, as Parma Ham. The samples were collected in three different periods, ranging from 2000 to 2003, 2012 to 2016 and 2018 to 2021. After serotyping, the isolates were phenotypically tested for resistance to three classes of antibiotics: s-lactams, fluoroquinolones and polymyxins. End-point polymerase chain reaction (PCR) and PCRReal Time were used for genotypical analyses. The phenotypical resistance to s-lactams and fluoroquinolones were clearly increasing when comparing the results obtained from isolates collected in the first period (16.7% and 16.7%, respectively) with those of the third period (29.7% and 32.4%, respectively). On the contrary, the resistance to colistin decreased from 33.3% to 5.4%. Genotypically, the 71.4% and 83.3% of the strains harboured s-lactams and fluoroquinolones genes, respectively, while colistin resistance genes were not detected in the phenotypically resistant strains.