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International Journal of Environmental... Apr 2024Using whey, a by-product of the cheese-making process, is important for maximizing resource efficiency and promoting sustainable practices in the food industry. Reusing...
Using whey, a by-product of the cheese-making process, is important for maximizing resource efficiency and promoting sustainable practices in the food industry. Reusing whey can help minimize environmental impact and produce bio-preservatives for foods with high bacterial loads, such as Mexican-style fresh cheeses. This research aims to evaluate the antimicrobial and physicochemical effect of CFS from 21/1 produced in a conventional culture medium (MRS broth) and another medium using whey (WB medium) when applied in Mexican-style fresh cheese inoculated with several indicator bacteria (, serovar Typhimurium, , and ). The CFSs (MRS or WB) were characterized for organic acids concentration, pH, and titratable acidity. By surface spreading, CFSs were tested on indicator bacteria inoculated in fresh cheese. Microbial counts were performed on inoculated cheeses during and after seven days of storage at 4 ± 1.0 °C. Moreover, pH and color were determined in cheeses with CFS treatment. Lactic and acetic acid were identified as the primary antimicrobial metabolites produced by the 21/1 fermentation in the food application. A longer storage time (7 days) led to significant reductions ( < 0.05) in the microbial population of the indicator bacteria inoculated in the cheese when it was treated with the CFSs (MRS or WB). serovar Typhimurium was the most sensitive bacteria, decreasing 1.60 ± 0.04 log CFU/g with MRS-CFS, whereas WB-CFS reduced the microbial population of to 1.67 log CFU/g. and were the most resistant at the end of storage. The cheese's pH with CFSs (MRS or WB) showed a significant reduction ( < 0.05) after CFS treatment, while the application of WB-CFS did not show greater differences in color (ΔE) compared with MRS-CFS. This study highlights the potential of CFS from 21/1 in the WB medium as an ecological bio-preservative for Mexican-style fresh cheese, aligning with the objectives of sustainable food production and guaranteeing food safety.
Topics: Cheese; Lacticaseibacillus casei; Whey; Food Microbiology; Hydrogen-Ion Concentration; Food Preservation; Mexico; Fermentation
PubMed: 38791776
DOI: 10.3390/ijerph21050560 -
Foods (Basel, Switzerland) May 2024In the context of climate change and depletion of natural resources, meeting the growing demand for animal feed and human food through sufficient, nutritious, safe, and...
In the context of climate change and depletion of natural resources, meeting the growing demand for animal feed and human food through sufficient, nutritious, safe, and affordable sources of protein is becoming a priority. The use of , the black soldier fly (BSF), has emerged as a strategy to enhance the circularity of the agri-food chain, but its microbiological safety remains a concern. The aim of the present study was to systematically review available data on the microbiological quality of BSF and to investigate the impact of using four different rearing substrates including classic options allowed by the EU regulation (cereals, fruits, vegetables) and options not allowed by EU regulations regarding vegetable agri-food (co-products, food at shelf life, and meat). A total of 13 studies were collected and synthesized, including 910 sample results, while 102 new sample results were collected from the present experiments in three farms. Both datasets combined revealed a high level of contamination of larvae, potentially transmitted through the substrate. The main pathogenic bacteria identified were , , spp., , spp., and coagulase-positive, while spp. and were not detected. Any of these four substrates were excluded for their use in insect rearing; however, safety concerns were confirmed and must be managed by the operators of the sector using microbial inactivation treatment after the harvest of the larvae in order to propose safe products for the market. The results obtained will guide the definition of the control criteria and optimize the following manufacturing steps.
PubMed: 38790886
DOI: 10.3390/foods13101587 -
Foods (Basel, Switzerland) May 2024The microbiological quality of dairy products from small-scale producers in Serbia was analysed. A total of 302 dairy products [raw ( = 111) and pasteurized milk cheeses...
The microbiological quality of dairy products from small-scale producers in Serbia was analysed. A total of 302 dairy products [raw ( = 111) and pasteurized milk cheeses ( = 79) and kajmak ( = 112)], were collected and tested for the presence of pathogens, and spp., and enumerated for Coagulase-positive staphylococci (CPS), , and yeasts and moulds. None of the samples tested positive for spp., while was recovered from one raw milk cheese and five kajmak samples. Raw milk cheese and kajmak also had higher levels of indicator microorganisms, namely and yeast and moulds. Molecular serotyping grouped isolates into serogroups 1 (1/2a and 3a) and 3 (1/2b, 3b, and 7). When exposed to eight antibiotics, isolates were mostly sensitive, with the exception of oxacillin and reduced susceptibility to clindamycin, penicillin G, and trimethoprim/sulfamethoxazole, emphasizing the importance of continuous surveillance for antimicrobial resistance. Samples that tested positive for spp. also had higher loads of indicator microorganisms, namely and yeast and moulds, suggesting lapses in hygiene practices during production. Collectively, these data emphasize the need for improved food safety and hygiene practices among small-scale dairy producers. This is crucial to reduce the microbial contamination and improve both the quality and safety of dairy products in the Serbian market.
PubMed: 38790756
DOI: 10.3390/foods13101456 -
Antioxidants (Basel, Switzerland) Apr 2024A commercial olive leaf extract (OL), effective against , , , and , was added to three different coating formulations (methylcellulose, MC; chitosan, CT; and alginate,...
A commercial olive leaf extract (OL), effective against , , , and , was added to three different coating formulations (methylcellulose, MC; chitosan, CT; and alginate, ALG) to produce active polylactic acid (PLA) coated films. Evaluation of these coated PLA films revealed significant inhibition of growth, particularly with the MC and CT formulations exhibiting the highest inhibition rates (99.7%). The coated films were then tested for food contact compatibility with three food simulants (A: 10% ethanol; B: 3% acetic acid; D2: olive oil), selected to assess their suitability for pre-cut hams and ready-to-eat vegetables in relation to overall migration. However, coated films with active functions exhibited migration values in simulants A and B above legal limits, while promising results were obtained for simulant D2, highlighting the need to deeply investigate these coatings' impact on a real food system. Untargeted metabolomics revealed that the type of coating influenced the selective release of certain phenolic classes based on the food simulant tested. The Oxitest analysis of simulant D2 demonstrated that the MC and ALG-coated PLA films slightly slowed down the oxidation of this food simulant, which is an edible vegetable oil.
PubMed: 38790624
DOI: 10.3390/antiox13050519 -
Antibiotics (Basel, Switzerland) May 2024, a foodborne pathogen, exhibits high adaptability to adverse environmental conditions and is common in the food industry, especially in ready-to-eat foods. strains...
, a foodborne pathogen, exhibits high adaptability to adverse environmental conditions and is common in the food industry, especially in ready-to-eat foods. strains pose food safety challenges due to their ability to form biofilms, increased resistance to disinfectants, and long-term persistence in the environment. The aim of this study was to evaluate the presence and genetic diversity of in food and related environmental products collected from 2014 to 2022 and assess antibiotic susceptibility and biofilm formation abilities. was identified in 13 out of the 227 (6%) of samples, 7 from food products (meat preparation, cheeses, and raw milk) and 6 from food-processing environments (slaughterhouse-floor and catering establishments). All isolates exhibited high biofilm-forming capacity and antibiotic susceptibility testing showed resistance to several classes of antibiotics, especially trimethoprim-sulfamethoxazole and erythromycin. Genotyping and core-genome clustering identified eight sequence types and a cluster of three very closely related ST3 isolates (all from food), suggesting a common contamination source. Whole-genome sequencing (WGS) analysis revealed resistance genes conferring resistance to fosfomycin (), lincosamides (), fluoroquinolones (), and tetracycline (). In addition, the gene was also detected, conferring resistance to disinfecting agents and antiseptics. Virulence gene profiling revealed the presence of 92 associated genes associated with pathogenicity, adherence, and persistence. These findings underscore the presence of strains in food products and food-associated environments, demonstrating a high virulence of these strains associated with resistance genes to antibiotics, but also to disinfectants and antiseptics. Moreover, they emphasize the need for continuous surveillance, effective risk assessment, and rigorous control measures to minimize the public health risks associated to severe infections, particularly listeriosis outbreaks. A better understanding of the complex dynamics of pathogens in food products and their associated environments can help improve overall food safety and develop more effective strategies to prevent severe health consequences and economic losses.
PubMed: 38786175
DOI: 10.3390/antibiotics13050447 -
Emerging Infectious Diseases Jun 2024Food irradiation can reduce foodborne illnesses but is rarely used in the United States. We determined whether outbreaks related to Campylobacter, Salmonella,...
Food irradiation can reduce foodborne illnesses but is rarely used in the United States. We determined whether outbreaks related to Campylobacter, Salmonella, Escherichia coli, and Listeria monocytogenes were linked to irradiation-eligible foods. Of 482 outbreaks, 155 (32.2%) were linked to an irradiation-eligible food, none of which were known to be irradiated.
Topics: Humans; Disease Outbreaks; United States; Foodborne Diseases; Food Microbiology; Food Irradiation; History, 21st Century
PubMed: 38781985
DOI: 10.3201/eid3006.230922 -
International Journal of Food... Jul 2024In 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...
Selection of starter lactic acid bacteria capable of forming biofilms on wooden vat prototypes for their future application in traditional Sicilian goat's milk cheese making.
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. Overall, this study contributes to establishing a custom-made LAB starter cultures with bio-preservatives properties for Sicilian cheese productions.
Topics: Cheese; Animals; Biofilms; Goats; Milk; Wood; Food Microbiology; Sicily; Lactobacillales; RNA, Ribosomal, 16S; Anti-Bacterial Agents; Random Amplified Polymorphic DNA Technique; Listeria monocytogenes
PubMed: 38781647
DOI: 10.1016/j.ijfoodmicro.2024.110752 -
Biofilm Jun 2024is one of the leading causative agents of foodborne disease outbreaks worldwide. Herein, the antibiofilm effect and mechanism of Mannosylerythritol Lipid-A against...
is one of the leading causative agents of foodborne disease outbreaks worldwide. Herein, the antibiofilm effect and mechanism of Mannosylerythritol Lipid-A against EGD-e is reported for the first time. MEL-A effectively attenuated biofilm formation while reducing the viability and motility of bacteria within the biofilm in the early stage, and influenced bacterial adhesion by affecting the secretion of extracellular polysaccharides and eDNA. RT-qPCR revealed that MEL-A significantly suppressed the expression of genes involved in flagellar movement and virulence. Untargeted LC-MS metabolomics indicated that MEL-A affected the fluidity and permeability of cell membranes by significantly upregulating unsaturated fatty acids, lipids and glycoside metabolites, and affected protein biosynthesis, nucleotide metabolism and DNA synthesis and repair by significantly downregulating amino acid metabolism and nucleic acid metabolism. These pathways may constitute the key targets of biofilm formation inhibition by MEL-A. Furthermore, MEL-A showed good removal effects on mature biofilms under different temperatures, different materials and milk. Our data indicated that MEL-A could be used as a novel antibiofilm agent to improve food safety. Our study provides new insights into the possible inhibitory mechanism of MEL-A and the response of EGD-e to MEL-A.
PubMed: 38779407
DOI: 10.1016/j.bioflm.2024.100201 -
MSphere Jun 2024The placenta is a critical barrier against viral, bacterial, and eukaryotic pathogens. For most teratogenic pathogens, the precise molecular mechanisms of placental...
The placenta is a critical barrier against viral, bacterial, and eukaryotic pathogens. For most teratogenic pathogens, the precise molecular mechanisms of placental resistance are still being unraveled. Given the importance of understanding these mechanisms and challenges in replicating trophoblast-pathogen interactions using models, we tested an existing stem-cell-derived model of trophoblast development for its relevance to infection with . We grew human trophoblast stem cells (TS) under conditions leading to either syncytiotrophoblast (TS) or cytotrophoblast (TS) and infected them with . We evaluated proliferation and invasion, cell ultrastructure, as well as for transcriptome changes after infection. TS cells showed similar ultrastructure compared to primary cells and villous explants when analyzed by transmission electron microscopy and scanning electron microscopy (SEM), a resistance to adhesion could be visualized on the SEM level. Furthermore, TS were highly refractory to parasite adhesion and replication, while TS were not. RNA-seq data on mock-treated and infected cells identified differences between cell types as well as how they responded to infection. We also evaluated if TS-derived SYNs and CYTs had distinct resistance profiles to another vertically transmitted facultative intracellular pathogen, . We demonstrate that TS are highly resistant to , while TS are not. Like , TS resistance to was at the level of bacterial adhesion. Altogether, our data indicate that stem-cell-derived trophoblasts recapitulate resistance profiles of primary cells to and highlight the critical importance of the placental surface in cell-autonomous resistance to teratogens.IMPORTANCECongenital toxoplasmosis can cause a devastating consequence to the fetus. To reach the fetus's tissues, must cross the placenta barrier. However, how this parasite crosses the placenta and the precise molecular mechanisms of placental resistance to this parasite are still unknown. In this study, we aimed to characterize a new cellular model of human trophoblast stem cells to determine their resistance, susceptibility, and response to . Syncytiotrophoblast derived from trophoblast stem cells recapitulate the resistance profile similarly to placenta cells. We also showed that these cells are highly resistant to , at the level of bacterial adhesion. Our results suggest that resisting pathogen adhesion/attachment may be a generalized mechanism of syncytiotrophoblast resistance, and trophoblast stem cells represent a promising model to investigate cell-intrinsic mechanisms of resistance to pathogen adhesion and replication.
Topics: Trophoblasts; Toxoplasma; Humans; Listeria monocytogenes; Female; Pregnancy; Cell Adhesion; Placenta; Toxoplasmosis; Stem Cells
PubMed: 38771057
DOI: 10.1128/msphere.00748-23 -
Heliyon May 2024In the present study, growth potential of in steak tartare samples taken at retail and belonging to 13 brands marketed in Northern Italy was investigated. The samples...
In the present study, growth potential of in steak tartare samples taken at retail and belonging to 13 brands marketed in Northern Italy was investigated. The samples were submitted to microbiological and chemical-physical characterization. The data obtained were used as inputs for the application of the predictive microbiology software FSSP that allows the estimation of the growth of during the shelf-life. Lactic acid bacteria, the main component of the microflora, gave variable counts among the brands (from 3.38 to 6.24 log CFU/g). pH and a values were always higher than 5.3 and 0.96, respectively, thus they could not be considered as single efficient hurdles to prevent the growth of according to the EC Reg. 2073/2005; the same was observed for salt content (constantly <2 %) and nitrites (not quantifiable in all the samples, even if declared in some labels). Nevertheless, the combination of all the hurdles, evaluated by predictive microbiology using critical development factors, resulted in an estimated growth <0.5 log CFU/g throughout the shelf life; this output allowed us to consider all the steak tartare analysed as unfavourable substrate for growth. The information obtained could be useful for tartare producers as well as for competent authority to evaluate the effective risk concerning these typology of products.
PubMed: 38765030
DOI: 10.1016/j.heliyon.2024.e30883