Category Archives: Research

Research – Exploring Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Food-Producing Animals and Animal-Derived Foods

Posted on April 27, 2024 by | Leave a comment

MDPI

Abstract

Antimicrobials serve as crucial treatments in both veterinary and human medicine, aiding in the control and prevention of infectious diseases. However, their misuse or overuse has led to the emergence of antimicrobial resistance, posing a significant threat to public health. This review focuses on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in animals and their associated food products, which contribute to the proliferation of antimicrobial-resistant strains. Recent research has highlighted the presence of ESBL-producing E. coli in animals and animal-derived foods, with some studies indicating genetic similarities between these isolates and those found in human infections. This underscores the urgent need to address antimicrobial resistance as a pressing public health issue. More comprehensive studies are required to understand the evolving landscape of ESBLs and to develop strategic public health policies grounded in the One Health approach, aiming to control and mitigate their prevalence effectively.

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Posted in E.coli, ESBL, Extended Spectrum B Lactamase, Food Microbiology Research, Research

Research – Changes in the Quality and Microbial Communities of Precooked Seasoned Crayfish Tail Treated with Microwave and Biological Preservatives during Room Temperature Storage

Posted on April 27, 2024 by | Leave a comment

MDPI

Abstract

The qualities of precooked foods can be significantly changed by the microorganisms produced during room temperature storage. This work assessed the effects of different antibacterial treatments (CK, without any treatment; microwave treatment, MS; microwave treatment and biological preservatives, MSBP) on the physicochemical properties and microbial communities of precooked crayfish tails during room temperature storage. Only the combination of microwave sterilization and biological preservatives significantly inhibited spoilage, as evidenced by the total viable count (4.15 log CFU/g) after 3 days of room temperature storage, which satisfied the transit time of most logistics companies in China. Changes in pH and TVB-N were also significantly inhibited in the MSBP group compared with those in the CK and MS groups. More than 30 new volatile compounds were produced in the CK groups during room temperature storage. However, in the MSBP groups, the volatile compounds were almost unchanged. The correlations between the microbial composition and volatile compounds suggested that specific bacterial species with metabolic activities related to amino acid, energy, cofactor, and vitamin metabolism, as well as xenobiotics biodegradation and metabolism, were responsible for the changes in volatile compounds. These bacteria included Psychrobacter, Arthrobacter, Facklamia, Leucobacter, Corynebacterium, Erysipelothrix, Devosia, Dietzia, and Acidovorax. Overall, our findings provide a foundation for the development of strategies to inhibit spoilage in precooked crayfish tails stored at room temperature.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbial Spoilage, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research

Research – Temperature status of domestic refrigerators and its effect on the risk of listeriosis from ready-to-eat (RTE) cooked meat products.

Posted on April 25, 2024 by | Leave a comment

Science Direct

Abstract

Inadequate domestic refrigeration is frequently cited as a factor that contributes to foodborne poisoning and infection, and consumer behaviour in this regard can vary largely. This study provides insight into the temperature profiles of domestic refrigerators in the Netherlands and the impact on the number of listeriosis cases related to ready-to-eat (RTE) cooked meat products. A survey was conducted among Dutch consumers (n = 1020) to assess their knowledge and behaviour related to refrigerators. Out of these participants, 534 measured their refrigerator’s temperature, revealing an average temperature of 5.7 °C (standard deviation (SD) of 2.2 °C) with a maximum of 17 °C. Elderly people (65 years and older) had refrigerators with temperatures that were on average 0.6 °C higher than those of younger people (35 years or younger). The 24-hour temperature profiles of an additional set of actively surveyed refrigerators (n = 50) showed that the temperature measured on the upper shelf was significantly higher (mean 7.7 °C, SD 2.7 °C) than the temperature measured on the bottom shelf (5.7 °C, SD 2.1 °C). Quantitative Microbiological Risk Assessment (QMRA) predicted that the primary factors contributing to the risk of listeriosis were the initial concentration and the time and temperature during household storage. Scenario analysis revealed that storing opened RTE cooked meat products at home for either <7 days or at temperatures <7 °C resulted in a significant reduction of over 80 % in predicted illness cases. Among all illness cases, the elderly represented nearly 90 %. When assessing the impact of the disease in terms of Years of Life Lost (YLL), the contribution of the elderly was 59 %. Targeted communication, particularly directed towards the elderly, on the importance of storing RTE cooked meat products at the recommended temperature on the bottom or middle shelf as well as consuming within two to three days after opening, holds the potential to significantly reduce the number of cases.

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Posted in Food Microbiology Research, Listeria, Listeria monocytogenes, Research

Research – Photothermal pasteurization of paprika powder by ultra-high irradiance blue (405 nm) light: Impact on Salmonella inactivation and quality attributes

Posted on April 23, 2024 by | Leave a comment

Science Direct

Abstract

This study aimed to evaluate the inactivation efficacy of ultra-high irradiance blue (405 nm) LED treatments against Salmonella spp. in paprika powder and develop an alternative Weibull model to describe the inactivation kinetics. Paprika samples were inoculated with a Salmonella cocktail at a ratio of 1 mL/100 g (∼8.7 log CFU/g), acclimated for 7 days at 22 °C, and irradiated with blue LED at a fixed distance (5 cm) using different irradiances (548, 697, and 842 mW/cm2) and exposure times (60, 120, 180, and 240 s). Sterilization-like temperatures of up to 131.7 °C were observed in paprika after 240 s at 842 mW/cm2. Reduction levels in Salmonella counts ranged from 2.1 to 7.8 logs after 240 s. A modified Weibull model satisfactorily described the Salmonella inactivation kinetics (𝑅adj2 > 0.98). Compared to control samples, a significant decrease in redness (a* values) and higher DPPH scavenging activity were observed in treated paprika powders.

Industrial relevance: The obtained results indicated that UHI LED technology could serve as an alternative dry pasteurization method to improve the microbiological safety of spices. This would open further possibilities, including the use of this technology to disinfect food-contact surfaces in dry operations. These findings are thus important in supporting the development and optimization of LED technology for food safety applications in the food industry. Blue light has a shorter penetration depth, which may limit the size and shape of products that can be pasteurized with UHI blue LED technology.

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Posted in Food Microbiology Research, Research, Salmonella, ultra-high irradiance blue (405 nm) light

Research – Food Safety News Publisher’s Platform: What you need to know about Botulism

Posted on April 22, 2024 by | Leave a comment

Food Safety News

Botulism is a rare, life-threatening paralytic illness caused by neurotoxins produced by an anaerobic, gram-positive, spore-forming bacterium, Clostridium botulinum.[1] Unlike Clostridium perfringens, which requires the ingestion of large numbers of viable cells to cause symptoms, the symptoms of botulism are caused by the ingestion of highly toxic, soluble exotoxins produced by C. botulinum while growing in foods.[2] These rod-shaped bacteria grow best under anaerobic (or, low oxygen), low-salt, and low-acid conditions.[3] Bacterial growth is inhibited by refrigeration below 4° C., heating above 121° C, and high water-activity or acidity.[4] And although the toxin is destroyed by heating to 85° C. for at least five minutes, the spores formed by the bacteria are not inactivated unless the food is heated under high pressure to 121° C. for at least twenty minutes.[5] C. botulinum bacteria and spores are widely distributed in nature, because they are indigenous to soils and waters.[6] They occur in both cultivated and forest soils, bottom sediment of streams, lakes, and coastal waters, in the intestinal tracts of fish and mammals, and in the gills and viscera of crabs and other shellfish.[7]

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Posted in Clostridium, Clostridium botulinum, Food Microbiology Research, Research

England – Salmonella infections return to pre-pandemic levels in England

Posted on April 22, 2024 by | Leave a comment

Food Safety News

The number of Salmonella cases in England has returned to pre-COVID-19 pandemic levels and 11 outbreaks were reported in 2022.

Salmonella Enteritidis went back to being the most frequently reported serovar and Salmonella Typhimurium infections also increased, said the UK Health Security Agency (UKHSA).

In 2022, there were 8,125 Salmonella cases in England, compared to 5,033 in 2021, 4,712 in 2020 and 8,398 in 2019.

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Posted in food bourne outbreak, Food Illness, Food Microbiology Research, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, outbreak, Research, Salmonella

Research – Onsite Detection of Multiple Foodborne Bacteria Achieved Within One Hour Using Handheld Device

Posted on April 21, 2024 by | Leave a comment

Food Safety.com

Researchers from Osaka Metropolitan University have achieved rapid, simultaneous detection of multiple foodborne bacteria with a handheld electrochemical device, which sends results to a smartphone app for convenient interpretation of results.

The biosensor-based technology was able to detect Escherichia coli and Staphylococcus aureus in real-world samples, onsite and within an hour. Time-wise, the new device offers a vast improvement over traditional, culture-based methods conducted in a laboratory, which can take days to produce results.

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Posted in E.coli, Food Microbiology Research, Food Technology, Research, Staphylococcal Toxin, Staphylococcus aureus, Technology

Research – Effect of food environment on the ability of microorganisms to form biofilms

Posted on April 21, 2024 by | Leave a comment

Wiley Online

Abstract

The aim of this study is to understand the effect of the food product’s, even in trace amounts, in the biofilm formation potential of Escherichia coli and Staphylococcus aureus. Bacterial adhesion was tested using three different food media, in which bacterial cells were adapted before determining how this would affect their adhesion score and biofilm formation potential: sterilized milk, mineral water, and pasteurized commercial orange juice. After characterization of the bacteria and the adhesion support by the contact angle, the adhesion score obtained by the theoretical mathematical model XDLVO developed by van Oss was compared to that obtained by the experimental approach, in order to examine the role of non-specific (thermodynamic) and specific (biological) interactions in adhesion. Changes in the membrane composition of bacteria, as a function of acclimation conditions, were evaluated by infrared spectroscopy. Results reveal variability in the spectral region between 900 and 1200 cm−1 specific to capsular polysaccharides (CPS) or lipopolysaccharides (LPS), and also in the range between 2800 and 3000 cm−1 characteristic of membrane lipids and phospholipids. Biofilm formation by S. aureus and E. coli was affected by commercial UHT milk. This led to increased hydrophobicity and total adhesion energy within the environment of these strains. However, no correlation was observed between the adhesion scores obtained through experimental and theoretical approaches. This underscores the necessity of considering the specific characteristics of individual food products in understanding the phenomenon of biofilm formation. Understanding, the mechanism, the variations in bacterial surface characteristics, and the conditions that favor or disadvantage the formation of biofilms, may have important implications, in the development of preventive and curative strategies, to control of food-borne infections.

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Posted in Biofilm, E.coli, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Staphylococcus aureus

Research – Assessment of the chemical profile and potential biocontrol of Amphora coffeaeformis against foodborne pathogens and Culex pipiens L. to ensure food safety

Posted on April 21, 2024 by | Leave a comment

Wiley Online

Abstract

The extensive use of synthetic antibiotics and insecticides in controlling microbes and insect spreads led to a build-up of resistance strains and caused negative impacts on human health through bioaccumulation in food and the environment. The present study assessed the antimicrobial activity of Amphora coffeaeformis (A. coffeaeformis) ethanolic extract against foodborne pathogenic microbes as well as assessed its ability to control Culex pipiens L. (C. pipiens) larvae. The gas chromatography–mass spectrum (GC/MS) and high-performance liquid chromatography (HPLC) analysis showed that A. coffeaeformis extract was rich with phenolic compounds, organosulfur compounds, carboxylic acids, amino acids, organic quinoline, dipeptide and monosaccharide. The extract of A. coffeaeformis showed antibacterial capability against all tested bacteria, with minimal inhibition concentration (MIC) values ranging from 20.2 to 66.7 g/mL, as well as antifungal effects against all tested mycotoxigenic fungi, with MIC values ranging from 113.62, 68.95 and 49.37 μg/mL mg/mL. Furthermore, the extract showed high larvicidal activity against C. pipiens larvae at 24, 48, and 72 h, respectively. LC50 values decreased gradually with the treatment period. Likewise, the adult emergence and growth index were significantly negatively related to increasing extract concentrations. Moreover, the extract exhibited a noteworthy depletion in the reproductive potential and increased sterility index of C. pipiens females developed of treated larvae. Besides a reduction in egg hatching percent, increase pupal malformations, increase and adult abnormalities. C. pipiens biochemical markers; glutathione-S-transferase, carboxylesterase, acetylcholinesterase, α-esterase and cytochrome P-450 showed significant alteration after the extract exposure. Overall, these findings promise the application possibility of A. coffeaeformis extract as a biopreservator against foodborne pathogens and as bioinsecticides for mosquito control as well.

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Posted in Emerging Pathogen, Food Microbiology Research, Food Pathogen, Pathogen, pathogenic, Research

Research – Non-O1/Non-O139 Vibrio cholerae—An Underestimated Foodborne Pathogen? An Overview of Its Virulence Genes and Regulatory Systems Involved in Pathogenesis

Posted on April 21, 2024 by | Leave a comment

MDPI

Abstract

In recent years, the number of foodborne infections with non-O1 and non-O139 Vibrio cholerae (NOVC) has increased worldwide. These have ranged from sporadic infection cases to localized outbreaks. The majority of case reports describe self-limiting gastroenteritis. However, severe gastroenteritis and even cholera-like symptoms have also been described. All reported diarrheal cases can be traced back to the consumption of contaminated seafood. As climate change alters the habitats and distribution patterns of aquatic bacteria, there is a possibility that the number of infections and outbreaks caused by Vibrio spp. will further increase, especially in countries where raw or undercooked seafood is consumed or clean drinking water is lacking. Against this background, this review article focuses on a possible infection pathway and how NOVC can survive in the human host after oral ingestion, colonize intestinal epithelial cells, express virulence factors causing diarrhea, and is excreted by the human host to return to the environment.

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Posted in Food Microbiology Research, Research, Vibrio, Vibrio cholera, vibrio cholerae