Anti-infective properties of the protective culture Hafnia alvei B16 in food and intestinal models against multi-drug resistant Salmonella.

Salmonella enterica is a ubiquitous and multi-host pathogen that causes significant morbidity and mortality worldwide. Outbreaks of foodborne salmonellosis continue to occur, highlighting the need for additional interventions. The present study investigated the potential for the commercial protective culture Hafnia alvei B16 to provide enhanced protection against multi-drug resistant strains of S. enterica serovars Typhimurium and Newport by attenuating their virulence when cocultured in milk (as a model food) and broth, and by protecting intestinal epithelial cells from pathogen infection in vitro. Exposure to HA in milk inhibited the subsequent adhesion of S. Typhimurium by 95.23%, whereas the invasion capacity of both serovars was reduced when cocultured with HA in broth and milk. The inhibition of invasion by S. Typhimurium and S. Newport was greater when cocultured in milk (86.95% and 86.58%, respectively) compared to broth (51.64% and 79.88%, respectively). Exposure to HA in both media decreased the expression of virulence genes in S. Typhimurium and S. Newport. Pre-treatment of Caco-2 cells with HA reduced invasion of S. Newport by 89.68% compared to control. These data demonstrate the potential for HA to enhance food safety by attenuating Salmonella virulence and protecting against pathogen invasion of intestinal epithelial cells.

The effect of protective cultures on Staphylococcus aureus growth and enterotoxin production.

Staphylococcus aureus is the causative agent of staphylococcal food poisoning and is a common contaminant in milk. Despite efforts to control S. aureus, recalls and outbreaks continue to occur, highlighting the need for additional interventions. This study determined the potential for protective cultures (PC) that are commercially available to producers to control S. aureus growth in raw milk and attenuate virulence by impeding staphylococcal enterotoxin (SE) production in raw milk and laboratory medium. Cultures of Hafnia alvei and Lactococcus lactis effectively inhibited S. aureus growth in raw milk to counts ~5 log CFU/mL lower than control when cocultured following a cheesemaking time and temperature profile; two cultures of Lactobacillus plantarum inhibited growth to ~1.5 log CFU/mL less than control. Cocultures of S. aureus with Lc. lactis, H. alvei and Lb. plantarum in raw milk reduced SE levels by 24.9%, 62.4%, and 76%, respectively. Lc. lactis also decreased SE production in raw milk in the absence of PC-mediated growth inhibition. Significant reductions in SE production in the absence of pathogen growth inhibition were also achieved in laboratory medium. Together, these results demonstrate the potential for PCs to inhibit S. aureus growth and impede SE production in the absence of growth inhibition.

Short communication: A countrywide survey of antimicrobial-resistant indicator bacteria in Kosovo's dairy farms.

The World Health Organization recently recognized the Republic of Kosovo as one of the highest consumers per capita of antibiotics for human use among non-European Union Eastern European countries; however, data are limited regarding antimicrobial usage and antimicrobial resistance in the livestock sector for this recently formed country. The objective of this study was to conduct the first nationwide survey of antimicrobial resistance phenotypes in indicator bacteria collected from dairy farms in Kosovo. Composite fecal samples were collected from 52 farms located within all 7 administrative districts of Kosovo in the summer of 2014. Isolation and characterization of the indicator bacteria Escherichia coli (n = 165) and Enterococcus spp. (n = 153) from these samples was achieved by culturing on selective/differential media with and without select antibiotics, followed by MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry-based identification and antimicrobial susceptibility testing using the disk diffusion method. When no selective pressure was applied in culture-based isolation, the majority of E. coli and Enterococcus spp. collected were resistant to ≤1 of 16 and ≤2 of 12 antibiotics tested, respectively. In contrast, E. coli and Enterococcus spp. isolated using sub-minimum inhibitory concentrations of cefoxitin, ciprofloxacin, or erythromycin were typically resistant to at least one and often multiple antibiotic types, which primarily consisted of certain ß-lactams, quinolones, sulfonamides, phenicols, and tetracyclines for E. coli isolates and macrolides, tetracyclines, and rifamycins for enterococci isolates.

Food safety knowledge and practices among food handlers and consumers in Gulf countries: An integrative review.

Foodborne illnesses result from inadequate food handling practices, but prevention is possible through implementing food safety principles by handlers and consumers. This paper presents an overview of food safety knowledge and practices among food handlers and consumers in the Gulf countries, identifies factors affecting knowledge and practice, and offers recommendations for promoting food safety among handlers and consumers. A literature search was conducted using an integrative review method. Various combinations of the following descriptors were used: (food safety, food hygiene), (knowledge, practice), and (Saudi Arabia, Qatar, UAE, Bahrain, Oman, and Kuwait). Out of 164 studies screened, 37 met the eligibility criteria. Food handler studies reported insufficient food safety knowledge, with poor translation of existing knowledge into practice. Consumer studies showed varying levels of food safety knowledge, and the translation of existing knowledge into practice was also found to be inconsistent. Training and educational level were the primary factors positively affecting food safety knowledge and practices. Overall, significant gaps in knowledge and practices were identified among food handlers and consumers in the Gulf. These gaps require urgent attention from the Gulf regulatory bodies to develop targeted food safety training and education programs to enhance awareness and implementation of food safety principles.

Mycological evaluation of frozen meat with special reference to yeasts.

Background and Aim: Fungi can play beneficial and detrimental roles in meat products; however, the diversity and significance of fungi in meat products are poorly understood. This study aimed to isolate and characterize fungal species from frozen beef samples collected from retail stores in the Qena Governorate, Egypt. Materials and Methods: A total of 70 frozen beef samples were collected from retail stores in Qena, Egypt. All samples were subjected to mycological examination. Fungal colonies were identified using conventional approaches, as well as the VITEK 2 system and DNA sequencing of the internal transcribed spacer region. Analyses of enzymatic activity, biofilm formation ability, and the antimicrobial resistance profiles of the isolated yeasts were also conducted. Results: Molds and yeasts were isolated from 40% and 60% of meat samples, respectively. Mold isolates were dominated by Aspergillus, Penicillium, and Cladosporium spp., whereas yeast isolates were identified as Candida albicans, Candida parapsilosis, Yarrowia lipolytica, Saccharomyces cerevisiae, and Rhodotorula mucilaginosa. Compared to other yeast species, the highest production of lipase and protease was observed in Candida species. The strongest ability to form biofilms was observed in Candida spp., followed by S. cerevisiae, Y. lipolytica, and R. mucilaginosa. The results of antimicrobial susceptibility testing revealed that all yeast isolates showed notable resistance to fluconazole and itraconazole. Conclusion: A significant correlation between antimicrobial resistance and biofilm formation was observed in several species. This study highlights the importance of the dangers of yeasts in food products and the extent of their impact on public health.

Probiotic potential of commercial dairy-associated protective cultures: In vitro and in vivo protection against Listeria monocytogenes infection.

Protective bacterial cultures (PCs) are commercially available to producers to control undesirable microbes in foods, including foodborne pathogens such as Listeria monocytogenes. They are generally recognized as safe for consumption and many are capable of producing bacteriocins. Yet their potential to act as probiotics and confer a health benefit on the host is not known. This study investigated the ability of three commercial PCs to survive human gastrointestinal conditions and exert anti-infective properties against L. monocytogenes. Counts of two PCs of Lactiplantibacillus plantarum remained unchanged after exposure to simulated gastrointestinal conditions, whereas counts of the PC Lactococcus lactis subsp. lactis were reduced by 5.3 log CFU/mL. Cultures of Lactiplantibacillus plantarum and Lactococcus lactis subsp. lactis adhered to human Caco-2 epithelial cells at âˆ¼ 6 log CFU/mL. This pretreatment reduced subsequent L. monocytogenes adhesion and invasion by 1-1.6 log CFU/mL and 3.8-4.9 log CFU/mL, respectively, compared to control. L. monocytogenes-induced cytotoxicity was also reduced from 29.1% in untreated monolayers to âˆ¼ 8% in those treated with PCs. Pretreatment of Caco-2 monolayers with Lactococcus lactis subsp. lactis and one PC of Lactiplantibacillus plantarum reduced L. monocytogenes translocation by ≥ 1.2 log CFU/mL compared to control (≥ 94.5% inhibition). All PCs significantly reduced DextranFITC permeability through Caco-2 monolayers to approximately half that of control. Pretreatment with PCs also reduced L. monocytogenes-induced mortality in Caenorhabditis elegans. These findings demonstrate the potential for commercially produced PCs to exert probiotic effects in the host through protection against L. monocytogenes infection, thus providing an additional benefit to food safety beyond inhibiting pathogen growth, survival, and virulence in foods.

Compatibility of Commercially Produced Protective Cultures with Common Cheesemaking Cultures and Their Antagonistic Effect on Foodborne Pathogens.

ABSTRACT: The documented survival of pathogenic bacteria, including Listeria monocytogenes (LM), Shiga toxin-producing Escherichia coli (STEC), and Salmonella during the manufacture and aging of some cheeses highlights the need for additional interventions to enhance food safety. Unfortunately, few interventions are compliant with the Standards of Identity for cheese. Protective bacterial cultures (PCs) represent actionable, natural interventions. However, supportive data for commercially produced PCs regarding their efficacy against pathogens and potential antagonism with each other and cheesemaking cultures are scant, thereby impeding their potential use by the cheese industry. The overall objective of this study was to identify commercially produced PCs that exert antimicrobial activity toward pathogens with minimal impact on beneficial cheese microbes. Direct antagonism and agar well diffusion assays were used to determine the impact of 10 commercially produced PCs on the growth of starter cultures and cultures of ripening bacteria and fungi. Deferred antagonism was used to evaluate the potential for antimicrobial effects against LM, STEC, and Salmonella. PCs and starter cultures were cocultured in ultrahigh-temperature-processed milk to determine the effects of coculture on starter acidification profiles when incubated according to a simulated cheesemaking temperature profile (4 h at 35°C followed by 20 h at 20°C). Compatibility assays suggest that PC antagonism is microbe and strain specific. Only one PC negatively impacted the acidification of the starters tested. PC antagonism of ripening bacteria and fungi growth varied but was consistent within species. All PCs displayed deferred inhibition of LM, STEC, and Salmonella growth, but to varying degrees. These data identify commercial PCs with potential for the control of pathogens and characterize their compatibility with cheesemaking cultures for future use by cheesemakers and investigations of their efficacy in the production of cheese.