Category Archives: Research

Research – The microbiological quality of flour products in the UK with respect to Salmonella and Shiga-toxin-producing Escherichia coli

Posted on August 1, 2024 by | Leave a comment

Applied Microbiology

Abstract

Aim

To investigate the possible contamination of raw flour and raw flour-based products, such as pancake/batter mixes, with Salmonella, generic Escherichia coli, and Shiga-toxin-producing E. coli (STEC). Samples included flours available for sale in the UK over a period of four months (January to April 2020). The Bread and Flour regulations, 1998 state the permitted ingredients in flour and bread but it does not specify the regular monitoring of the microbiological quality of flour and flour-based products.

Methods and results

Samples of raw flour were collected by local authority sampling officers in accordance with current guidance on microbiological food sampling then transported to the laboratory for examination. Microbiological testing was performed to detect Salmonella spp., generic E. coli, and STEC characterized for the presence of STEC virulence genes: stx1, stx2, and subtypes, eae, ipah, aggR, lt, sth, and stp, using molecular methods Polymerase Chain Reaction (PCR). Of the 882 flours sampled, the incidence of Salmonella was 0.1% (a single positive sample that contained multiple ingredients such as flour, dried egg, and dried milk, milled in the UK), and 68 samples (7.7%) contained generic E. coli at a level of >20 CFU/g. Molecular characterization of flour samples revealed the presence of the Shiga-toxin (stx) gene in 10 samples (5 imported and 5 from the UK) (1.1%), from which STEC was isolated from 7 samples (0.8%). Salmonella and STEC isolates were sequenced to provide further characterization of genotypes and to compare to sequences of human clinical isolates held in the UKHSA archive. Using our interpretive criteria based on genetic similarity, none of the STEC flour isolates correlated with previously observed human cases, while the singular Salmonella serotype Newport isolate from the mixed ingredient product was similar to a human case in 2019, from the UK, of S. Newport. Although there have been no reported human cases of STEC matching the isolates from these flour samples, some of the same serotypes and stx subtypes detected are known to have caused illness in other contexts.

Conclusion

Results indicate that while the incidence was low, there is a potential for the presence of Salmonella and STEC in flour, and a genetic link was demonstrated between a Salmonella isolate from a flour-based product and a human case of salmonellosis.

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Posted in Food Microbiology Research, Research, Salmonella, STEC, STEC E.coli, STX 1, STX 2

Ireland – FSAI reminds consumers on cooking duck eggs before consumption – Salmonella

Posted on August 1, 2024 by | Leave a comment

FSAI

hazegg.jpg

The Food Safety Authority of Ireland (FSAI) today would like to remind consumers of its advice that duck eggs should only be eaten after they have been thoroughly cooked. Consumers should not use raw duck eggs in any dishes that will not be cooked thoroughly before eating. The FSAI, together with the National Health Protection Office of the HSE, are currently investigating an outbreak of illness involving five human cases of Salmonellosis within the last 12 months and linked to the consumption of duck eggs. The investigation is ongoing.

Duck eggs are legitimately available on the Irish retail market and are used by some people instead of hens’ eggs in cooking and baking. Producers are responsible for ensuring the safety of food placed on the market. However, from time-to-time, Salmonella occurs in duck eggs. Salmonella can cause serious illness. The risk is greatest for people who are very young, for older people, and for people who have a suppressed immune system.

The FSAI advises consumers to only eat duck eggs that have been thoroughly cooked and to only use raw duck eggs in dishes that will be cooked thoroughly before eating. Maintaining stringent hygiene practices, such as washing hands and preparation surfaces, is important when handling or breaking raw duck eggs. Therefore, duck eggs should always be handled and cooked carefully.

Specifically, it is advised that:

  • Duck eggs should not be eaten raw or lightly cooked.
  • Duck eggs should only be eaten after they have been thoroughly cooked, until both the white and yolk are solid. A duck egg is heavier and larger than a hen’s egg, and therefore needs more cooking time.
  • Dishes that contain duck eggs should be cooked until they are piping hot all the way through.
  • Do not use raw duck eggs in the preparation of products that contain raw or lightly cooked egg, such as homemade mayonnaise, tiramisu, icing, hollandaise sauce.
  • When using duck eggs in cooking or baking, pay attention to hygiene when breaking duck eggs and handling the empty shells afterwards, and do not eat or taste the raw mix.
  • After handling raw duck eggs, always wash hands thoroughly.
  • Ensure all utensils and preparation surfaces that have been in contact with raw duck eggs are washed thoroughly before being re-used.
  • Store duck eggs in the fridge away from ready-to-eat food.

The investigation into the outbreak is ongoing and the FSAI will provide further updates, as necessary.

For more information, see our Q&A advice for consumers and Health Protection Surveillance Centre Factsheet on Salmonella.

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Posted in Food Microbiology Research, Research, Salmonella, Salmonella in Eggs

Hong Kong – Roving Exhibitions on Food Safety in 2024

Posted on August 1, 2024 by | Leave a comment

CFS

Date Time Venue Theme
7/8 10am – 4pm Tsz Wan Shan Shopping Centre 5 Keys for Food Safety, Control of Food Temperature; Natural Toxins
 14/8 10am – 4pm Scenic View Nutrition Labelling, Prevention of Cross-contamination; Natural Toxins
 16/8 10am – 4pm Trade and Industry Tower 5 Keys for Food Safety, Veterinary Drug Residues; Trans Fats
21/8 10am – 4pm To Kwa Wan Market Nutrition Labelling, Genetically Modified Food; Trans Fats
28/8 10am – 4pm Lockhart Road Market Nutrition Labelling, Control of Food Temperature; Prevention of Cross-contamination

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Posted in CFS, Food Microbiology Research, Research

USDA Proposes New Policy to Reduce Salmonella in Raw Poultry Products

Posted on July 30, 2024 by | Leave a comment

FSIS USDA

WASHINGTON, July 29, 2024 – The U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) today issued a comprehensive proposed rule and determination to more effectively reduce Salmonella contamination and illnesses associated with raw poultry products. This is the culmination of FSIS’ three-year effort to re-evaluate their strategy for controlling Salmonella rates in poultry and protect American consumers from foodborne illness linked to consumption of poultry products.

Salmonella bacteria cause over 1 million human infections in the United States each year, according to the Centers for Disease Control and Prevention (CDC). Food is the leading source of Salmonella infections and poultry is among the leading sources of foodborne Salmonella illnesses. FSIS estimates that there are 125,000 chicken-associated and almost 43,000 turkey-associated foodborne Salmonella illnesses per year. Despite FSIS data indicating that Salmonella contamination in poultry products has been decreasing, there has not been an observed reduction in Salmonella illnesses.

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Posted in Food Microbiology Research, Food Safety, Food Safety Management, Food Safety Regulations, food safety training, Research, Salmonella, Salmonella in Chicken

Research – Public health aspects of Vibrio spp. related to the consumption of seafood in the EU

Posted on July 28, 2024 by | Leave a comment

EFSA

Abstract

Vibrio parahaemolyticus, Vibrio vulnificus and non‐O1/non‐O139 Vibrio cholerae are the Vibrio spp. of highest relevance for public health in the EU through seafood consumption. Infection with V. parahaemolyticus is associated with the haemolysins thermostable direct haemolysin (TDH) and TDH‐related haemolysin (TRH) and mainly leads to acute gastroenteritis. V. vulnificus infections can lead to sepsis and death in susceptible individuals. V. cholerae non‐O1/non‐O139 can cause mild gastroenteritis or lead to severe infections, including sepsis, in susceptible individuals. The pooled prevalence estimate in seafood is 19.6% (95% CI 13.7–27.4), 6.1% (95% CI 3.0–11.8) and 4.1% (95% CI 2.4–6.9) for V. parahaemolyticus, V. vulnificus and non‐choleragenic V. cholerae, respectively. Approximately one out of five V. parahaemolyticus‐positive samples contain pathogenic strains. A large spectrum of antimicrobial resistances, some of which are intrinsic, has been found in vibrios isolated from seafood or food‐borne infections in Europe. Genes conferring resistance to medically important antimicrobials and associated with mobile genetic elements are increasingly detected in vibrios. Temperature and salinity are the most relevant drivers for Vibrio abundance in the aquatic environment. It is anticipated that the occurrence and levels of the relevant Vibrio spp. in seafood will increase in response to coastal warming and extreme weather events, especially in low‐salinity/brackish waters. While some measures, like high‐pressure processing, irradiation or depuration reduce the levels of Vibrio spp. in seafood, maintaining the cold chain is important to prevent their growth. Available risk assessments addressed V. parahaemolyticus in various types of seafood and V. vulnificus in raw oysters and octopus. A quantitative microbiological risk assessment relevant in an EU context would be V. parahaemolyticus in bivalve molluscs (oysters), evaluating the effect of mitigations, especially in a climate change scenario. Knowledge gaps related to Vibrio spp. in seafood and aquatic environments are identified and future research needs are prioritised.

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Posted in Food Microbiology Research, Research, Vibrio, vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificans

Research – Shiga Toxin-Producing Escherichia coli Strains from Romania: A Whole Genome-Based Description

Posted on July 28, 2024 by | Leave a comment

MDPI

Abstract

The zoonotic Shiga toxin-producing Escherichia coli (STEC) group is unanimously regarded as exceptionally hazardous for humans. This study aimed to provide a genomic perspective on the STEC recovered sporadically from humans and have a foundation of internationally comparable data. Fifty clinical STEC isolates, representing the culture-confirmed infections reported by the STEC Reference Laboratory between 2016 and 2023, were subjected to whole-genome sequencing (WGS) analysis and sequences were interpreted using both commercial and public free bioinformatics tools. The WGS analysis revealed a genetically diverse population of STEC dominated by non-O157 serogroups commonly reported in human STEC infections in the European Union. The O26:H11 strains of ST21 lineage played a major role in the clinical disease resulting in hospitalisation and cases of paediatric HUS in Romania surpassing the O157:H7 strains. The latter were all clade 7 and mostly ST1804. Notably, among the Romanian isolates was a stx2a-harbouring cryptic clade I strain associated with a HUS case, stx2f– and stx2e-positive strains, and hybrid strains displaying a mixture of intestinal and extra intestinal virulence genes were found. As a clearer picture emerges of the STEC strains responsible for infections in Romania, further surveillance efforts are needed to uncover their prevalence, sources, and reservoirs.

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Posted in E.coli O157, E.coli O157:H7, Food Microbiology Research, HUS, Research, STEC, STEC E.coli, STX 1, STX 2, WGS

Research – Avoid Botulism with Safe Canning Tips

Posted on July 28, 2024 by | Leave a comment

Food Poisoning News

Home canning has long been a popular method for preserving fresh fruits and vegetables, allowing food enthusiasts to enjoy their favorite produce year-round. However, the U.S. Food and Drug Administration (FDA) and the American Medical Association (AMA) warn that improperly canned foods can pose a serious health risk, potentially causing botulism – a rare but deadly kind of food poisoning.

Earlier this month, Food Poisoning News reported on a botulism outbreak at two family events in California linked to the consumption of a salad containing home-canned cactus pads.  Ten people were hospitalized and two sisters were in intensive care as of July 8th.

Botulism, a rare but potentially fatal form of food poisoning, can occur when the bacterium Clostridium botulinum grows and produces toxins.  Symptoms of botulism can include general weakness, dizziness, double vision, difficulty speaking or swallowing, breathing problems, muscle weakness, abdominal distension, and constipation. These symptoms may appear anywhere from six hours to two weeks after consuming contaminated food.

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

Research – Foodborne bacteria in milk and milk products along the water buffalo milk chain in Bangladesh

Posted on July 28, 2024 by | Leave a comment

Nature

Abstract

Controlling foodborne pathogens in buffalo milk is crucial for ensuring food safety. This study estimated the prevalence of nine target genes representing seven critical foodborne bacteria in milk and milk products, and identified factors associated with their presence in buffalo milk chain nodes in Bangladesh. One hundred and forty-three milk samples from bulk tank milk (n = 34), middlemen (n = 37), milk collection centers (n = 37), and milk product shops (n = 35) were collected and analyzed using RT-PCR. Escherichia (E.) coli, represented through yccT genes, was the most prevalent throughout the milk chain (81–97%). Chi-squared tests were performed to identify the potential risk factors associated with the presence of foodborne bacteria encoded for different genes. At the middleman level, the prevalence of E. coli was associated with the Mymensingh, Noakhali, and Bhola districts (P = 0.01). The prevalence of Listeria monocytogenes, represented through inlA genes, and Yersinia (Y.) enterocolitica, represented through yst genes, were the highest at the farm level (65–79%). The prevalence of both bacteria in bulk milk was associated with the Noakhali and Bhola districts (P < 0.05). The prevalence of Y. enterocolitica in bulk milk was also associated with late autumn and spring (P = 0.01) and was higher in buffalo-cow mixed milk than in pure buffalo milk at the milk collection center level (P < 0.01). The gene stx2 encoding for Shiga toxin-producing (STEC) E. coli was detected in 74% of the milk products. At the middleman level, the prevalence of STEC E. coli was associated with the use of cloths or tissues when drying milk containers (P = 0.01). Salmonella enterica, represented through the presence of invA gene, was most commonly detected (14%) at the milk collection center. The use of plastic milk containers was associated with a higher prevalence of Staphylococcus aureus, represented through htrA genes, at milk product shops (P < 0.05). These results suggest that raw milk consumers in Bangladesh are at risk if they purchase and consume unpasteurized milk.

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Posted in E.coli, Emerging Pathogen, Food Microbiology Research, Food Pathogen, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Research, Salmonella, STEC, STEC E.coli

Research – Determinants of Sporadic Shiga Toxin-Producing Escherichia coli (STEC) Infection in Denmark, 2018–2020: A Matched Case–Control Study

Posted on July 27, 2024 by | Leave a comment

MDPI

Abstract

Infections with Shiga toxin-producing Escherichia coli (STEC) are increasing in Denmark and elsewhere. STEC is also the most frequent cause of haemolytic uraemic syndrome (HUS) in Danish children. Most cases are considered sporadic, while approximately one-third can be attributed to a known source of infection. Hence, we examined sources of sporadic STEC infection in Denmark. From January 2018 to December 2020, we conducted a prospective nationwide case–control study among Danish adults and children. Cases with confirmed positive STEC infection were notified infections within the national laboratory surveillance system. Control persons were randomly selected from the Danish Civil Registration System, individually matched in age in 5-year bands and sex. Participants were invited by an electronic letter to complete either an adult or child questionnaire online. Univariate and adjusted matched odds ratios were computed for adults and children using conditional logistic regression. The study recruited 1583 STEC cases and 6228 controls. A total of 658 cases (42%) and 2155 controls (35%) were included in the analysis. Depending on age, univariate analysis adjusted for socio-demographic determinants showed that the consumption of boiled beef (mOR = 2.2, 95% confidence interval (CI): 1.6–3.1) and fried minced beef (mOR = 1.6, CI: 1.2–2.1), drinking raw (unpasteurized) milk (mOR = 11, CI 1.1–110), eating grilled food (mOR = 9.8, CI: 5.6–17) and having a household member using diapers (mOR = 2.1, CI: 1.4–3.2) were determinants of sporadic STEC infection. Further multivariate adjusted analysis resulted in the same determinants. This study confirms that beef is an overall important risk factor for STEC infection in Denmark. We also present evidence that a proportion of sporadic STEC infections in Denmark are determined by age-specific eating habits, environmental exposures and household structure, rather than being exclusively food-related. These findings are relevant for targeted public health actions and guidelines.

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Posted in Food Microbiology Research, Haemolytic Uremic Syndrome, HUS, Research, STEC, STEC E.coli

Research – Impact of Biotic and Abiotic Factors on Listeria monocytogenes, Salmonella enterica, and Enterohemorrhagic Escherichia coli in Agricultural Soil Extracts

Posted on July 27, 2024 by | Leave a comment

MDPI

Abstract

Outbreaks of Enterohemorrhagic Escherichia coli (EHEC), Salmonella enterica, and Listeria monocytogenes linked to fresh produce consumption pose significant food safety concerns. These pathogens can contaminate pre-harvest produce through various routes, including contaminated water. Soil physicochemical properties and flooding can influence pathogen survival in soils. We investigated survival of EHEC, S. enterica, and L. monocytogenes in soil extracts designed to represent soils with stagnant water. We hypothesized pathogen survival would be influenced by soil extract nutrient levels and the presence of native microbes. A chemical analysis revealed higher levels of total nitrogen, phosphorus, and carbon in high-nutrient soil extracts compared to low-nutrient extracts. Pathogen survival was enhanced in high-nutrient, sterile soil extracts, while the presence of native microbes reduced pathogen numbers. A microbiome analysis showed greater diversity in low-nutrient soil extracts, with distinct microbial compositions between extract types. Our findings highlight the importance of soil nutrient composition and microbial dynamics in influencing pathogen behavior. Given key soil parameters, a long short-term memory model (LSTM) effectively predicted pathogen survival. Integrating these factors can aid in developing predictive models for pathogen persistence in agricultural systems. Overall, our study contributes to understanding the complex interplay in agricultural ecosystems, facilitating informed decision-making for crop production and food safety enhancement.

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Posted in EHEC, Food Microbiology Research, Food Pathogen, Food Technology, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Research, Salmonella, STEC, STEC E.coli, Technology