Category Archives: Microbiology

Research – Bromine and Chlorine Disinfection of Cryptosporidium parvum Oocysts, Bacillus atrophaeus Spores, and MS2 Coliphage in Water

Posted on June 9, 2023 by | Leave a comment

Pubs Acs Org

Abstract

Abstract Image

Conventional water treatment practices utilizing chemical disinfection, especially chlorination, are considered generally effective in producing microbiologically safe drinking water. However, protozoan pathogens such as oocysts of Cryptosporidium parvum are very resistant to chlorine, which has led to consideration of alternative disinfectants for their control. Free bromine, HOBr, has not been evaluated extensively as an alternative halogen disinfectant for inactivation of Cryptosporidium parvum in drinking water or reclaimed water for non-potable uses. Bromine is a versatile disinfectant consisting of different chemical forms with persistent microbicidal efficacy under varied water quality conditions and is effective against a range of waterborne microbes of health concern. The objectives of this study are to (1) compare the efficacy of free bromine to free chlorine at similar concentrations (as milligrams per liter) for disinfection of Cryptosporidium parvum oocysts, Bacillus atrophaeus spores, and MS2 coliphage in a model buffered water and (2) evaluate the kinetics of inactivation of these microorganisms using appropriate disinfection models. Overall, at a target concentration of ∼5 mg/L, bromine averaged 0.6 log (73.8%) reductions of C. parvum oocyst infectivity after 300 min (CT: 1166 min·mg/L) and produced up to a 0.8 log reduction disinfectant activity. An ∼5.0 mg/L chlorine dose increased oocyst infectivity by only 0.4 log (64%) after 300 min (CT: 895 min·mg/L). Bacillus atrophaeus spores and MS2 coliphage treated with bromine and chlorine were reduced by 4 log10 (99.99%) for both disinfectants over the duration of the experiments.

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Posted in Bacillus, Contaminated water, Cryptosporidiosis, Cryptosporidium, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Water, water microbiology

Research – Bactericidal efficacy and mechanism of alkaline electrolyzed water co-action with acidic electrolyzed water on Pseudomonas aeruginosa biofilm

Posted on June 8, 2023 by | Leave a comment

Wiley Online

Abstract

Here, the bactericidal efficacy and mechanism of action of the combination of alkaline electrolyzed water (AlEW) and acidic electrolyzed water (AcEW) on Pseudomonas aeruginosa biofilm were investigated, in comparison with single AcEW or AlEW treatment. The mature P. aeruginosa biofilm was formed at 120 h of cultivation. The number of bacteria in the P. aeruginosa biofilm decreased by 7.87 and 2.51 Lg CFU/mL after single AcEW and single AlEW treatment for 8 min, while the sterilization rate reached 92.2% and 33.1%, respectively. The group of AcEW (7 min) co-action with AlEW (1 min) had a P. aeruginosa sterilization rate of 85%. The AlEW (3 min) co-action with AcEW (5 min) treatment showed the best bactericidal efficacy. With this treatment, the sterilization rate achieved 94.4%, and the extracellular protein, polysaccharide, and DNA were degraded with the ratios of 70.8%, 77.7%, and 70.5%, respectively. Thus, AlEW exhibited a major washing effect, which can destroy the biofilm structure of extracellular polymers to a certain extent, while AcEW displayed a significant bactericidal effect. These results suggest that the AlEW co-action with AcEW treatment may be a promising candidate suitable for bacterial biofilm sterilization.

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Posted in Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pseudomonas, Pseudomonas aeruginosa, Technology

Research – Flesh-Eating Bacteria Seem to Thrive on Plastic And Seaweed Blooms – Vibrio

Posted on June 7, 2023 by | Leave a comment

Science Alert

Vibrio bacteria are known to feast on marine plant and animal tissues on the coastline. When humans consume seafood or seawater infected with these pathogens, they can cause life-threatening illnesses like cholera. The species Vibrio vulnificus can even infect wounds, risking life-threatening destruction of surrounding tissue.

Finding a number of Vibrio species, some of which are undescribed, happily living their best life on waste is far from good news. It’s yet another potential vector for human disease that experts have not accounted for. Even worse, the floating habitat isn’t going anywhere. In fact, it seems to be expanding in size and washing up on our coastlines like never before.

The recent analysis from Florida Atlantic University included samples of ocean plastic collected in the Caribbean and Sargasso Seas in 2012 and 2013, as well as samples of brown seaweed, called Sargassum, eel larvae, and seawater.

In both the plastic and seaweed samples, the team found multiple species of Vibrio bacteria, some of which have never been seen before.

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

Research – Laboratory fishing expedition reels in a big catch: hidden pathogenic role of a housekeeping enzyme in Listeria

Posted on June 6, 2023 by | Leave a comment

Purdue Edu

Purdue University doctoral student Dongqi Liu has identified a previously unknown strategy that the foodborne bacterium Listeria monocytogenes uses to invade and infect humans and animals.

“Listeria is a huge problem in the food industry and for people who get infected,” said Arun Bhunia, a food microbiology professor in the Department of Food Science at Purdue. L. monocytogenes infects an estimated 1,600 each year in the U.S., resulting in about 260 deaths. At highest risk are pregnant women, unborn fetuses, immune-compromised and elderly people.

Bhunia’s previous research has shown that the Listeria adhesion protein (LAP) plays an important role in helping L. monocytogenes to pass through the gut barrier.

But a question lingered about the LAP. After the pathogen secretes LAP, the protein stays on the bacterium’s surface. How it does so remained a mystery. LAP must stay fastened to the bacterial surface for Listeria to cause infection.

Read the Link Above  to find out 🙂

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

Research – Prevalence and Characterisation of Clostridium perfringens Isolates in Food-Producing Animals in Romania

Posted on June 5, 2023 by | Leave a comment

MDPI

Abstract

The aim of the current study was to investigate the prevalence of Clostridium perfringens (C. perfringens) recovered from animal faeces, as well as to determine the antimicrobial susceptibility of such isolates. A total of 14 (14/100; 14%) C. perfringens isolates were isolated from the 100 analysed samples (twelve recovered from faecal samples collected from pigs and two from veal calves’ faecal samples). The preponderant genotype was type A, with all isolates being cpa-positive. The most potent antimicrobial agents against C. perfringens proved to be vancomycin, rifampicin and lincomycin. A strong resistance to tetracycline (71.4%), penicillin (64.2%), erythromycin (42.8%) and enrofloxacin (35.7%) was also observed. To the best of our knowledge, this is the first analysis regarding the prevalence, characterization and antimicrobial susceptibility of C. perfringens in food-producing animals in Romania, adding further evidence for the probable role of animals as a source of resistant C. perfringens strains.

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

Research – Cronobacter Species in the Built Food Production Environment: A Review on Persistence, Pathogenicity, Regulation and Detection Methods

Posted on June 4, 2023 by | Leave a comment

MDPI

Abstract

The powdered formula market is large and growing, with sales and manufacturing increasing by 120% between 2012 and 2021. With this growing market, there must come an increasing emphasis on maintaining a high standard of hygiene to ensure a safe product. In particular, Cronobacter species pose a risk to public health through their potential to cause severe illness in susceptible infants who consume contaminated powdered infant formula (PIF). Assessment of this risk is dependent on determining prevalence in PIF-producing factories, which can be challenging to measure with the heterogeneity observed in the design of built process facilities. There is also a potential risk of bacterial growth occurring during rehydration, given the observed persistence of Cronobacter in desiccated conditions. In addition, novel detection methods are emerging to effectively track and monitor Cronobacter species across the food chain. This review will explore the different vehicles that lead to Cronobacter species’ environmental persistence in the food production environment, as well as their pathogenicity, detection methods and the regulatory framework surrounding PIF manufacturing that ensures a safe product for the global consumer.

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

Research – Can Non-Toxigenic Vibrio cholerae Reduce a Cholera Infection?

Posted on June 3, 2023 by | Leave a comment

CRIS Haifa

Abstract

Vibrio cholerae, is the causative agent of cholera, that infects millions, annually. Chironomids are aquatic insects that host V. cholerae. Toxigenic strains produce cholera toxin (CT) which is the main virulence factor that causes cholera symptoms. In contrast to other bacterial pathogens, V. cholerae produces CT when at low cell densities while hemagglutinin/protease (HAP) is a high cell density-controlled gene. When V. cholerae behavior was examined on chironomids, we showed that high cell densities of non-toxigenic strains, increased HAP production in a toxigenic strain, conditions which could also potentially reduce CT production. Here we propose the value of studies that could support the potential of V. cholerae non-toxigenic strains to repress virulence gene expression in cholera-infected humans. High cell densities of a non-toxigenic strain present in an infected individual, may down-regulate CT expression, reducing cholera symptoms. To further test the hypothesis supported by a chironomid model, additional experiments in animal models are first needed.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Vibrio, Vibrio cholera, vibrio cholerae

Research – Microbiological Safety and Quality of Fermented Products

Posted on June 2, 2023 by | Leave a comment

MDPI

Fermented foods, which have emerged fortuitously over the course of human development, have become an essential part of human history worldwide. These rich and diverse fermented foods not only have unique flavors and qualities that appeal to local preferences but also embody local cultures and play a significant role in human life. Despite the popularity of fermented foods globally, many traditional fermented foods are still produced using open fermentation methods where it is difficult to evaluate the safety or function of microorganisms, leading to inevitable challenges. Therefore, to advance the knowledge on the functional properties of microorganisms in fermented foods globally, and shed light on the impact of these microorganisms on the safety and quality of fermented foods, we present “Microbiological Safety and Quality of Fermented Products”, a Special Issue publishing 10 papers.
This Special Issue covers four pivotal research topics. First, the microbial safety of fermented products, where researchers have focused on identifying food-borne pathogens in particular fermented products through detection methods, thereby improving the safety levels and reducing the harms of fermented products. Second, the functions of microorganisms in fermented foods have been investigated. Third, researchers have explored the application of microorganisms in various stages of fermented food production, for example, in pre-treatment, fermentation, and post-fermentation processes. Fourth, researchers have analyzed the changes in microflora during the different stages of fermenting food, providing crucial evidence for understanding the role played by microbes in creating distinctive flavor and quality.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, food safety training, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Food poisoning can be passed on through sex -Campylobacter

Posted on June 2, 2023 by | Leave a comment

New Telegraph

Interesting headline as Campylobacter is not a food poisoning organism.

Researchers in the United States (U.S.) have found that Campylobacter infection, the most common foodborne illness in the Western world, can also be spread through sexual contact. To this end, the researchers from the University of Oklahoma had called on doctors to talk to their patients about risks associated with sexual contact amid a bout of food poisoning. Some Campylobacter species can infect humans, sometimes causing campylobacteriosis, a diarrhoeal disease in humans. While campylobacter infection was rarely serious, it can cause vomiting and diarrhoea, and can pose an additional risk for people with underlying health conditions. In the study, the team set out to understand whether Campylobacter infection can be spread through sexual contact. Dr. Katrin Kuhn, who led the study, said: “This research is important for public health messaging and for physicians as they talk to their patients about risks associated with sexual contact. “Although Campylobacter infection is usually not a serious disease, it causes diarrhoea, which can result in people missing work, losing productivity or perhaps losing their job.”

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Posted in Campylobacter, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

Research – Risk Factors for Non-O157 Shiga Toxin–Producing Escherichia coli Infections, United States

Posted on June 1, 2023 by | Leave a comment

CDC

Abstract

Shiga toxin–producing Escherichia coli (STEC) causes acute diarrheal illness. To determine risk factors for non-O157 STEC infection, we enrolled 939 patients and 2,464 healthy controls in a case–control study conducted in 10 US sites. The highest population-attributable fractions for domestically acquired infections were for eating lettuce (39%), tomatoes (21%), or at a fast-food restaurant (23%). Exposures with 10%–19% population attributable fractions included eating at a table service restaurant, eating watermelon, eating chicken, pork, beef, or iceberg lettuce prepared in a restaurant, eating exotic fruit, taking acid-reducing medication, and living or working on or visiting a farm. Significant exposures with high individual-level risk (odds ratio >10) among those >1 year of age who did not travel internationally were all from farm animal environments. To markedly decrease the number of STEC-related illnesses, prevention measures should focus on decreasing contamination of produce and improving the safety of foods prepared in restaurants.

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Posted in Decontamination Microbial, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, STEC, STEC E.coli