Category Archives: Decontamination Microbial

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

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.

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

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.

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

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.

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

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 🙂

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

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.

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

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.

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

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.

Research – Microbiological Safety and Quality of Fermented Products

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.

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

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.

Research – UAE: Counts of E.coli in vegetables from retailers in Abu Dhabi and Dubai

Horti Daily

A new study by Ihab Habib, Rami H Al-Rifai, Mohamed-Yousif Ibrahim Mohamed, Akela Ghazawi, Afra Abdalla, Glindya Lakshmi, Neveen Agamy and Mushtaq Khan investigates the counts, antimicrobial resistance profile, and genome-based characterization of Escherichia coli in 11 different types of fresh salad vegetable products (n = 400) sampled from retailers in Abu Dhabi and Dubai in the United Arab Emirates.

E. coli was detected in 30% of the tested fresh salad vegetable items, with 26.5% of the samples having an unsatisfactory level (≥100 CFU/g) of E. coli, notably arugula and spinach. The study also assessed the effect of the variability in sample conditions on E. coli counts and found, based on negative binominal regression analysis, that samples from local produce had a significantly higher (p-value < 0.001) E. coli count than imported samples.

The analysis also indicated that fresh salad vegetables from the soil-less farming system (e.g., hydroponic and aeroponic) had significantly (p-value < 0.001) fewer E. coli than those from traditional produce farming. The study also examined the antimicrobial resistance in E. coli (n = 145) recovered from fresh salad vegetables and found that isolates exhibited the highest phenotypic resistance toward ampicillin (20.68%), tetracycline (20%), and trimethoprim-sulfamethoxazole (10.35%).

A total of 20 (13.79%) of the 145 E. coli isolates exhibited a multidrug-resistant phenotype, all from locally sourced leafy salad vegetables. The study further characterized 18 of the 20 multidrug-resistant E. coli isolates using whole-genome sequencing and found that the isolates had varying numbers of virulence-related genes, ranging from 8 to 25 per isolate. The frequently observed genes likely involved in extra-intestinal infection were CsgA, FimH, iss, and afaA. The β-lactamases gene blaCTX-M-15 was prevalent in 50% (9/18) of the E. coli isolates identified from leafy salad vegetable samples.

The study highlights the potential risk of foodborne illness and the likely spread of antimicrobial resistance and resistance genes associated with consuming leafy salad vegetables. It emphasizes the importance of proper food safety practices, including appropriate storage and handling of fresh produce.

Click here to access the entire research.