Author Archives: KSW

Research – Clostridium perfringens—Opportunistic Foodborne Pathogen, Its Diversity and Epidemiological Significance

Posted on June 16, 2023 | Leave a comment

MDPI

CDC Clost perf

Abstract

The C. perfringens species is associated with various environments, such as soils, sewage, and food. However, it is also a component of the gastrointestinal (GI) microflora (i.e., microbiota) of sick and healthy humans and animals. C. perfringens is linked with different systemic and enteric diseases in livestock and humans, such as gas gangrene, food poisoning, non-foodborne diarrhoea, and enterocolitis. The strains of this opportunistic pathogen are known to secrete over 20 identified toxins that are considered its principal virulence factors. C. perfringens belongs to the anaerobic bacteria community but can also survive in the presence of oxygen. The short time between generations, the multi-production capability of toxins and heat-resistant spores, the location of many virulence genes on mobile genetic elements, and the inhabitance of this opportunistic pathogen in different ecological niches make C. perfringens a very important microorganism for public health protection. The epidemiological evidence for the association of these strains with C. perfringens–meditated food poisoning and some cases of non-foodborne diseases is very clear and well-documented. However, the genetic diversity and physiology of C. perfringens should still be studied in order to confirm the importance of suspected novel virulence traits. A very significant problem is the growing antibiotic resistance of C. perfringens strains. The aim of this review is to show the current basic information about the toxins, epidemiology, and genetic and molecular diversity of this opportunistic pathogen.

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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

Brazil – Toxins are detected in samples of curd cheese and artisan mozzarella in Brazil – Aflatoxins

Posted on June 15, 2023 | Leave a comment

Eurekalert

Strictly speaking, cheese should be completely free of aflatoxins, a class of toxic compounds that are produced by certain molds found in food, and can cause liver damage and cancer. In practice, however, the technology used to produce milk and cheese is unable to guarantee the total absence of aflatoxins, as demonstrated by research performed in several countries. In the latest study conducted in Brazil on this subject, a team of researchers analyzed 28 samples of curd cheese and mozzarella produced in Araripe, a subhumid area within the semi-arid region of Pernambuco State (Northeast Brazil). The samples were collected between March and May 2022.

The results are reported in an article published in the journal Toxins. The analysis revealed the presence of aflatoxins in all samples. The highest levels were found in artisan mozzarella, but none had more than 0.25 μg/kg (micrograms per kilogram). This is the upper limit permitted by the European Union and was chosen by the researchers as their parameter as well.

In Brazil, the limit for AFM1 is 2.5 μg/kg, ten times the maximum acceptable level in the EU.

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Posted in Aflatoxin, aflatoxin m1, Decontamination Microbial, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Mycotoxin

Research – Increased Incidence of Legionellosis after Improved Diagnostic Methods, New Zealand, 2000–2020

Posted on June 14, 2023 | Leave a comment

cdc

Abstract

Legionellosis, notably Legionnaires’ disease, is recognized globally and in New Zealand (Aotearoa) as a major cause of community-acquired pneumonia. We analyzed the temporal, geographic, and demographic epidemiology and microbiology of Legionnaires’ disease in New Zealand by using notification and laboratory-based surveillance data for 2000‒2020. We used Poisson regression models to estimate incidence rate ratios and 95% CIs to compare demographic and organism trends over 2 time periods (2000–2009 and 2010–2020). The mean annual incidence rate increased from 1.6 cases/100,000 population for 2000–2009 to 3.9 cases/100,000 population for 2010–2020. This increase corresponded with a change in diagnostic testing from predominantly serology with some culture to almost entirely molecular methods using PCR. There was also a marked shift in the identified dominant causative organism, from Legionella pneumophila to L. longbeachae. Surveillance for legionellosis could be further enhanced by greater use of molecular typing of isolates.

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Posted in Contaminated water, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Legionella, Legionnaires’ disease, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Water, water microbiology, Water Safety

Research – Antibacterial Activity against Four Fish Pathogenic Bacteria of Twelve Microalgae Species Isolated from Lagoons in Western Greece

Posted on June 13, 2023 | Leave a comment

MDPI

Abstract

Microalgae may produce a range of high-value bioactive substances, making them a promising resource for various applications. In this study, the antibacterial activity of twelve microalgae species isolated from lagoons in western Greece was examined against four fish pathogenic bacteria (Vibrio anguillarum, Aeromonas veronii, Vibrio alginolyticus, and Vibrio harveyi). Two experimental approaches were used to evaluate the inhibitory effect of microalgae on pathogenic bacteria. The first approach used bacteria-free microalgae cultures, whereas the second approach used filter-sterilized supernatant from centrifuged microalgae cultures. The results demonstrated that all microalgae had inhibitory effects against pathogenic bacteria in the first approach, particularly 4 days after inoculation, where Asteromonas gracilis and Tetraselmis sp. (red var., Pappas) exhibited the highest inhibitory activity, reducing bacterial growth by 1 to 3 log units. In the second approach, Tetraselmis sp. (red var., Pappas) showed significant inhibition against V. alginolyticus between 4 and 25 h after inoculation. Moreover, all tested cyanobacteria exhibited inhibitory activity against V. alginolyticus between 21 and 48 h after inoculation. Statistical analysis was performed using the independent samples t-test. These findings suggested that microalgae produce compounds with antibacterial activity, which could be useful in aquaculture.

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Posted in Aeromonas, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pathogen, pathogenic, Vibrio

Research – Detection, Remediation and Control of Biofilms

Posted on June 12, 2023 | Leave a comment

Food Safety Tech

Biofilms, those slimy films of bacteria that cling to surfaces, can wreak havoc on your equipment and harbor dangerous pathogens that contaminate your products. And they are not easy to detect or remove. Charles Giambrone, Food Safety Manager, Rochester Midland, shared strategies for the detection, remediation, and control of biofilms at the Food Safety Tech Hazards Conference in April.

“Biofilms are how microbes look to survive in nature and within your food plant,” said Giambrone, “and they can form quickly—within 13 hours.”

Biofilms form on any equipment with a large surface area and, in addition to contaminating food, they can damage equipment. “Once you get biofilms on the conveyor belts, you have slippage,” said Giambrone. “Just as biofilm plague will rot your teeth, biofilms form acid that corrode equipment. Eliminating biofilms can increase performance and prolong the lifespan of equipment.”

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

Posted on June 11, 2023 | 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, Shigatoxin, STEC, STEC E.coli, Toxin

Research – Cool for the Summer: Keep Your Favorite Salads Chilled

Posted on June 10, 2023 | Leave a comment

USDA

Vegetable Bacteria Danger

At your next picnic, let the spotlight shine on your food — not on party crashers like Salmonella or Listeria. When temperatures rise and food safety steps aren’t followed, cold dishes at a cookout are at risk for unsafe bacteria levels. Avoid foodborne illness by following these steps:
Clean: Remember to clean and sanitize all dishes and utensils used to make your salad and wash your hands before and after food prep.
Separate: Use different cutting boards, plates and utensils to avoid spreading bacteria when preparing your raw foods and ready-to-eat cold dishes.
Cook: Make sure the main meat or poultry ingredients used in cold salads (egg salad, chicken salad, etc.) are cooked to safe internal temperatures before mixing:
Cook eggs to 160 F.
Cook chicken to 165 F.
Although most cold salads use mayonnaise, the danger of foodborne illness lies with the main ingredient, such as eggs or chicken. Make sure they are cooked and chilled at the proper temperature. If you use homemade mayonnaise, follow these guidelines.
Chill: Avoid the Danger Zone (temperatures between 40 F and 140 F) by refrigerating perishable food within two hours — one hour if it’s a hot day (above 90 F). Keep cold foods at an internal temperature of 40 F or below by nestling food in ice or keeping food in a cooler.
For more information about food safety, call the USDA Meat and Poultry Hotline at 1-888-MPHotline (1-888-674-6854) or email MPHotline@usda.gov to reach a food safety specialist or chat live at ask.usda.gov from 10 a.m. to 6 p.m. Eastern Time, Monday through Friday.

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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 Management, food safety training, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella

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

Posted on June 9, 2023 | 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 | 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 | 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