Category Archives: Microbiology

Research – Cross-Contamination to Surfaces in Consumer Kitchens with MS2 as a Tracer Organism in Ground Turkey Patties

Journal of Food Protection

ABSTRACT

It is estimated that one in five cases of foodborne illnesses is acquired in the home. However, how pathogens move throughout a kitchen environment when consumers are preparing food is not well characterized. The purpose of this study was to determine the prevalence and degree of cross-contamination across a variety of kitchen surfaces during a consumer meal preparation event. Consumers (n = 371) prepared a meal consisting of turkey patties containing the bacteriophage MS2 as a tracer organism and a ready-to-eat lettuce salad. Half were shown a video on proper thermometer use before the trial. After meal preparation, environmental sampling and detection were performed to assess cross-contamination with MS2. For most surfaces, positivity did not exceed 20%, with the exception of spice containers, for which 48% of the samples showed evidence of MS2 cross-contamination. Spice containers also had the highest MS2 concentrations, at a mean exceeding 6 log viral genome equivalent copies per surface. The high level of MS2 on spice containers drove the significant differences between surfaces, suggesting the significance of spice containers as a vehicle for cross-contamination, despite the absence of previous reports to this effect. The thermometer safety intervention did not affect cross-contamination. The efficiency of MS2 transfer, when expressed as a percentage, was relatively low, ranging from an average of 0.002 to 0.07%. Quantitative risk assessment work using these data would aid in further understanding the significance of cross-contamination frequency and efficiency. Overall, these data will help create more targeted consumer messaging to better influence consumer cross-contamination behaviors.

HIGHLIGHTS
  • Forty-eight percent of spice containers sampled showed evidence of MS2 cross-contamination.
  • Spice containers had the highest MS2 concentrations across kitchen surfaces.
  • Spice containers may be a key vehicle for cross-contamination.
  • The thermometer safety intervention did not affect cross-contamination.
  • The efficiency of MS2 transfer was relatively low, ranging from 0.002 to 0.07%.

Research – Quantifying risk associated with changes in EHEC physiology during post-harvest pre-processing stages of leafy green production

CPS

Summary

The goal of this project is to determine if the time between harvest and end use of romaine lettuce impacts E. coli O157:H7 pathogenicity and detectability resulting in increased health risk. Laboratory scale experiments with inoculated lettuce undergoing simulated harvest and cooling will be used to measure changes in E. coli O157:H7 stress tolerance and virulence. Input from industry partners including temperature data from commercial romaine harvesting and cooling, and details on supply chain logistics, will be combined with the laboratory scale experimental data and used to model risk associated with specific harvest and handling practices. The resulting quantitative tool will be publicly available and allow for growers and producers to determine any practices that should be implemented to reduce the potential for O157 transmission on romaine lettuce.

Research – Foodborne Parasites and Their Complex Life Cycles Challenging Food Safety in Different Food Chains

MDPI

Abstract

Zoonotic foodborne parasites often represent complex, multi host life cycles with parasite stages in the hosts, but also in the environment. This manuscript aims to provide an overview of important zoonotic foodborne parasites, with a focus on the different food chains in which parasite stages may occur. We have chosen some examples of meat-borne parasites occurring in livestock (Taenia spp., Trichinella spp. and Toxoplasma gondii), as well as Fasciola spp., an example of a zoonotic parasite of livestock, but transmitted to humans via contaminated vegetables or water, covering the ‘farm to fork’ food chain; and meat-borne parasites occurring in wildlife (Trichinella spp., Toxoplasma gondii), covering the ‘forest to fork’ food chain. Moreover, fish-borne parasites (Clonorchis spp., Opisthorchis spp. and Anisakidae) covering the ‘pond/ocean/freshwater to fork’ food chain are reviewed. The increased popularity of consumption of raw and ready-to-eat meat, fish and vegetables may pose a risk for consumers, since most post-harvest processing measures do not always guarantee the complete removal of parasite stages or their effective inactivation. We also highlight the impact of increasing contact between wildlife, livestock and humans on food safety. Risk based approaches, and diagnostics and control/prevention tackled from an integrated, multipathogen and multidisciplinary point of view should be considered as well.

Research – Transmission Scenarios of Listeria monocytogenes on Small Ruminant On-Farm Dairies

MDPI

Abstract

Listeria monocytogenes can cause severe foodborne infections in humans and invasive diseases in different animal species, especially in small ruminants. Infection of sheep and goats can occur via contaminated feed or through the teat canal. Both infection pathways result in direct (e.g., raw milk from an infected udder or fresh cheese produced from such milk) or indirect exposure of consumers. The majority of dairy farmers produces a high-risk product, namely fresh cheese made from raw ewe’s and goat’s milk. This, and the fact that L. monocytogenes has an extraordinary viability, poses a significant challenge to on-farm dairies. Yet, surprisingly, almost no scientific studies have been conducted dealing with the hygiene and food safety aspects of directly marketed dairy products. L. monocytogenes prevalence studies on small ruminant on-farm dairies are especially limited. Therefore, it was our aim to focus on three main transmission scenarios of this important major foodborne pathogen: (i) the impact of caprine and ovine listerial mastitis; (ii) the significance of clinical listeriosis and outbreak scenarios; and (iii) the impact of farm management and feeding practices.

Research – Intervention Strategies to Control Campylobacter at Different Stages of the Food Chain

MDPI

Abstract

Campylobacter is one of the most common bacterial pathogens of food safety concern. Campylobacter jejuni infects chickens by 2–3 weeks of age and colonized chickens carry a high C. jejuni load in their gut without developing clinical disease. Contamination of meat products by gut contents is difficult to prevent because of the high numbers of C. jejuni in the gut, and the large percentage of birds infected. Therefore, effective intervention strategies to limit human infections of C. jejuni should prioritize the control of pathogen transmission along the food supply chain. To this end, there have been ongoing efforts to develop innovative ways to control foodborne pathogens in poultry to meet the growing customers’ demand for poultry meat that is free of foodborne pathogens. In this review, we discuss various approaches that are being undertaken to reduce Campylobacter load in live chickens (pre-harvest) and in carcasses (post-harvest). We also provide some insights into optimization of these approaches, which could potentially help improve the pre- and post-harvest practices for better control of Campylobacter.

Research – Pseudomonas fluorescens and Escherichia coli in Fresh Mozzarella Cheese: Effect of Cellobiose Oxidase on Microbiological Stability during Refrigerated Shelf Life

MDPI

Abstract

Background: Mozzarella cheese possesses a high moisture content (50–60%) and a relatively high pH (around 5.5) and is therefore considered a perishable food product characterized by high quality deterioration and the potential risk of microbial contamination. Moreover, it can be spoiled by Pseudomonas spp. and coliform bacteria, which may be involved in different negative phenomena, such as proteolysis, discolorations, pigmentation, and off-flavors. To prevent these, different methods were investigated. In this context, the present study aims to assess the antimicrobial effect of cellobiose oxidase on Pseudomonas fluorescens (5026) and Escherichia coli (k88, k99) in mozzarella cheese during refrigerated shelf life. Methods: microbiological challenge tests were designed by contaminating the mozzarella covering liquid containing different cellobiose oxidase concentrations with P. fluorescens (5026) and E. coli (k88, k99). The behavior of these microorganisms and the variation of hydrogen peroxide concentrations were then tested under refrigerated conditions for 20 days to simulate the mozzarella cheese shelf life. Results and Conclusions: The data obtained demonstrated the effect of cellobiose oxidase on microbial growth. In particular, E. coli (k88, k99) was inhibited over the entire shelf life, while P. fluorescens (5026) was only partially affected after a few days of refrigerated storage.

Research – Two Outbreaks of Foodborne Gastrointestinal Infection Linked to Consumption of Imported Melons, United Kingdom, March to August 2021 – Salmonella – STEC E.coli

Science Direct

Abstract

The aim of this study was to describe two foodborne outbreaks caused by contaminated imported melon and make recommendations for future practice. Between March and July 2021, there was an outbreak of 113 cases of Salmonella Braenderup in the UK (62% female, median age 61 years, 33% hospitalized). Analytical epidemiological studies identified Galia melons as the vehicle of infection (OR 671.9, 95% CI 39.0–58,074.0, p < 0.001). Subsequently, the outbreak strain was isolated from two samples of Galia melon imported from Latin America. In July and August 2021, there was an outbreak of 17 cases of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in the UK (53% female, median age 21 years, 35% were hospitalized). Review of the STEC surveillance questionnaire data, followed by the analysis of responses from a modified hypothesis-generating questionnaire, implicated eating precut watermelon from retailer B sourced from Europe as the vehicle of infection. Outbreaks of gastrointestinal pathogens caused by contaminated food of nonanimal origin are a global public health concern. Given the difficulty in removing pathogens from the flesh of ready-to-eat fruit and vegetables, public health interventions should target all steps of the food chain prior to consumption, from cultivation on the farm to processing/packing and distribution.

India – 43 Kerala Hotels Shut After 100 Fall Sick Due To Suspected Food Poisoning

NDTV

The Food Safety Department of Kerala government has conducted an inspection in 429 establishments across the state and shut down 43 hotels following the death of a woman in a suspected food poisoning incident at a religious event.

The inspections on Tuesday came in the backdrop of the death of a young woman in Kottayam after allegedly having food from a hotel.

The state health ministry said that among the 43 establishments, 21 were found out to be without a licence.

Apart from this, 22 establishments which were lacking cleanness have also been suspended from carrying on with their business.

Notices were issued to 138 institutions and 44 food samples have been sent for testing.

The ministry also stated that inspections would be continued intensively across the state.

On Sunday, Kerala Health Minister Veena George ordered the probe into a suspected food poisoning incident in which over 100 people fell ill. The incident occurred in the Keezvaipur area of the Pathanamthitta district of Kerala.

The affected people have been admitted to various hospitals in the district where they are currently undergoing treatment.

Algeria – Food poisoning leaves one dead, 144 injured in Algeria

Roya News

A woman died and 144 people were injured after suffering food poisoning in Algeria earlier this week.

According to local reports, people have eaten sweets that are unfit for human consumption in the city of Magra, east of the country.

Research – Campylobacter contamination in broiler meat

Poultry World

Campylobacter in broiler meat is one of the leading foodborne pathogens associated with health risks and negative economic impacts worldwide. Campylobacter has several adaptive responses throughout the broiler production chain. Thus, it survives from broiler farm to slaughterhouse and processing plant.