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Category Archives: Research
Research – Investigating the Impacts of UVC Radiation on Natural and Cultured Biofilms: An assessment of Cell Viability
Biofilms are conglomerates of cells, water, and extracellular polymeric substances which can lead to various functional and financial setbacks. As a result, there has been a drive towards more environmentally friendly antifouling methods, such as the use of ultraviolet C (UVC) radiation. When applying UVC radiation, it is important to understand how frequency, and thus dose, can influence an established biofilm. This study compares the impacts of varying doses of UVC radiation on both a monocultured biofilm consisting of Navicula incerta and field-developed biofilms. Both biofilms were exposed to doses of UVC radiation ranging from 1626.2 mJ/cm2mJ/cm2 to 9757.2 mJ/cm2mJ/cm2 and then treated with a live/dead assay. When exposed to UVC radiation, the N. incerta biofilms demonstrated a significant reduction in cell viability compared to the non-exposed samples, but all doses had similar viability results. The field biofilms were highly diverse, containing not only benthic diatoms but also planktonic species which may have led to inconsistencies. Although they are different from each other, these results provide beneficial data. Cultured biofilms provide insight into how diatom cells react to varying doses of UVC radiation, whereas the real-world heterogeneity of field biofilms is useful for determining the dosage needed to effectively prevent a biofilm. Both concepts are important when developing UVC radiation management plans that target established biofilms.
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, UV Microbiology, UV-C
Research – German testing finds Listeria and E. coli in raw milk
Listeria and E. coli have been found during testing of unpasteurized, raw milk from farms in Germany.
From 2020 to 2022, the Chemical and Veterinary Investigation Office (CVUA) in Stuttgart tested 54 raw milk samples from vending machines for a range of agents.
Parameters examined included somatic cell count, total germ count, spoilage organisms, hygiene indicator germs such as Enterobacteriaceae and E. coli, and pathogens like Salmonella, Listeria, Campylobacter, and Shiga toxin-producing E. coli (STEC).
The sale of raw milk is mostly prohibited but it can be sold directly on the farm via self-service vending machines. The producers should put up notices telling the consumers to boil raw milk before consumption.
Some findings were positive as 30 samples were compliant but 24 had issues. Results highlight the importance of regular cleaning of milking machines, pipes, and tanks at dairy farms, said scientists. Insufficient cooling can also lead to contamination of raw milk.
Posted in Campylobacter, Decontamination Microbial, E.coli, 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, Raw Milk, raw milk cheese, Raw Milk Cream, Research, Salmonella, STEC, STEC E.coli
Research – Rapid salmonella test poised to accelerate food safety in poultry
Researchers at McMaster University, Canada, have developed a test for Salmonella contamination that “provides accurate results in an hour or less.” The inexpensive test could improve food safety and mitigate broad recalls of contaminated food.
Salmonella is one of the primary contamination risks for poultry processors, with major chicken producers having to perform “tens of thousands” of lab tests each year to prevent the infection, which causes 155,000 deaths each year globally, according to the report.
The report notes that: “The Centers for Disease Control and Prevention (CDC) reports an estimated 450 deaths, 23,000 hospitalizations and US$365 million in direct medical costs are caused by Salmonella infection alone in the US each year.”
Reducing or eliminating the need for overnight Salmonella testing and replacing it with a rapid, easily-used test will save time and money, notes study co-author Yingfu Li, a Biochemistry and Chemical Biology professor and leader of McMaster’s Functional Nucleic Acids Research Group.
“Anyone can use it right in the setting where food is being prepared, processed or sold,” he says.
“There’s a balance between cost, convenience and need. If it’s cheap, reliable and easy, why not use it?”
Research – Classification and ranking of shigatoxin-producing Escherichia coli (STEC) genotypes detected in food based on potential public health impact using clinical data
Risk classification and management of shigatoxin-producing E. coli (STEC) isolated from food has been hampered by gaps in knowledge about the properties that determine the extent to which different subtypes of STEC can cause severe disease. Data on the proportion of infected human cases being affected by severe illness enables an evaluation of existing approaches for classifying STEC strains and the development of a new public health based approach. Evaluations show that existing approaches do not unequivocally classify different STEC variants according to their ability to cause severe disease. A new approach for ranking of STEC genotypes, combining the estimated probability of the strain to cause severe illness with the public health burden associated with the illness in terms of DALY per case, address these limitations. The result is a list of STEC genotypes in descending order of potential public health burden per case. The approach is risk based in considering the probability and consequences following infection (severe illness), and can support transparent risk management. This is illustrated by, arbitrarily, separating the ranked list of genotypes into classes based on the potential public health burden, and by characterising collections of strains isolated from different foods into different classes. Further, the classification of food samples as satisfactory or not based on the cost in terms of proportion of food being rejected and the benefit in terms of the proportion of strains causing severe illness (HUS) that are being captured is demonstrated using this approach.
Posted in Decontamination Microbial, eae, 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, STEC, STEC E.coli, STX 1, STX 2
Research – Escherichia coli, the Shiga toxin-producing serotype (STEC). Control measures in beef
Information based on the document published this year by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). Available information on the efficacy of physical, chemical and biological measures aimed at the control of Escherichia coli during the primary production and processing of raw beef, raw milk and raw milk cheeses is reviewed.
It should be said that there is a margin of uncertainty about the degree of effectiveness of the proposed measures given that, for the most part, they have been applied in small-scale production conditions, apart from the variability in the excretion of this Shiga toxin-producing serotype. (STEC) in cattle and, therefore, contamination of the products obtained.
Document is in Spanish but the translation can be read at the link above.
Posted in Food Microbiology Research, Research, STEC, STEC E.coli
Research – How filthy is YOUR phone? Stomach-churning study reveals the ‘invisible life’ lurking on the average device – including E.Coli from human POO
Bacteria from both human and cockroach poo are among the secret germs that lurk on our phones, experts have warned.
E.Coli and Fecal Streptococci were found on 100 per cent of smartphone screens in a study of the harmful microbes that plague our devices.
Food poisoning germ, Bacillus cereus, and pneumonia-causing S. aureus, were also found on each of the 20 swabs taken from 10 phones.
While none of them had traces of Salmonella, half of them did contain P. aeruginosa which is commonly found in cockroach poo.
Posted in Bacillus, Bacillus cereus, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pseudomonas, Pseudomonas aeruginosa, Research, Staphylococcus aureus
Research – CFA Briefing – Relevance of generic E coli (inc testing issues) to food safety
Escherichia coli (E. coli) is a bacterium commonly found in the gut of humans and warm-blooded
animals. Most strains of E. coli are harmless and some provide many health benefits to the host; for example,
they prevent colonization of the gut by harmful pathogens.
However, there are small groups of E.coli, referred to as pathogenic E.coli, that can cause severe disease in
humans, which are well known to be transmitted by food and/or water and have been implicated in major
food borne outbreaks worldwide e.g. radish sprouts in Japan, Sprouted seeds in Germany, raw / undercooked
beef products UK and USA.
This briefing note looks at the relevance of generic E coli to food safety referring to fresh produce and is also relevent to all food types.
With sections including transmisson, testing and prevention it concludes:
- A positive for E.coli O157 alone may not cause illness.
- The isolation of stx (Shiga toxins) gene has to be isolate in an E.coli, usually with a gene for attachment for the isolate to cause serious illness.
- All parties agree with the confirmed stage of the method, but FSA’s decision to call isolation of stx alone as presumptive is misleading.
- Action required in the event of a presumptive result is inappropriate and not possible for the industry.
- Food safety can only be controlled by routinely testing for indicator organisms e.g. generic E. coli and monitoring trends to proactively prompt investigation.
- HACCP and PRP’s are paramount, supported by environmental and product monitoring.
CFA 057 22 Briefing paper – relevance of generic E coli (inc testing issues) to food safety
Posted in E.coli, Food Microbiology Research, Research, STEC, STEC E.coli
Research – Joint FAO/WHO Expert Meeting on the pre-and post-harvest control of Campylobacter spp. in poultry meat
Research – Current Perspectives on Viable but Non-Culturable Foodborne Pathogenic Bacteria: A Review
Foodborne diseases caused by foodborne pathogens pose risks to food safety. Effective detection and efficient inactivation of pathogenic bacteria has always been a research hotspot in the field of food safety. Complicating these goals, bacteria can be induced to adopt a viable but non-culturable (VBNC) state under adverse external environmental stresses. When in the VBNC state, pathogens cannot form visible colonies during traditional culture but remain metabolically active and toxic. The resulting false negative results in growth-related assays can jeopardize food safety. This review summarizes the latest research on VBNC foodborne pathogens, including induction conditions, detection methods, mechanism of VBNC formation, and possible control strategies. It is hoped that this review can provide ideas and methods for future research on VBNC foodborne pathogenic bacteria.
Posted in 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, Research
Research – Detection of Escherichia coli O157:H7 in imported meat products from Saudi Arabian ports in 2017
Escherichia coli O157:H7 is a foodborne pathogen, which causes various health conditions in humans, including fatigue, nausea, bloody diarrhoea and in some cases, even death. In 2017, 15.71% of the total imported food products in Saudi Arabia (SA) were meat-based. India and Brazil are two of the top five countries from where SA imports meat. According to the Saudi Food and Drug Authority, in 2017, at least 562, 280, and 50 samples of imported beef, chicken and sheep meat, respectively, were tested for the presence of E. coli O157:H7. Amongst these, E. coli O157:H7 was detected in respectively 6.80% and 2.20% of the tested beef meat samples imported from India and Brazil as well as in respectively 6.96% and 3.57% of the tested chicken samples imported from Brazil and Ukraine. Moreover, the pathogen was detected in 2.13% of the tested sheep meat samples imported from India. The present report provides evidence that imported meat can serve as the carrier of E. coli O157:H7, which may lead to epidemics within the Kingdom of Saudi Arabia.
Posted in 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, Research, STEC, STEC E.coli