Category Archives: Pathogen

Research – Surveillance and characteristics of food-borne outbreaks in the Netherlands, 2006 to 2019

Eurosurveillance

A wide variety of pathogens can cause disease in humans through the consumption of contaminated food [13]. Contamination of food can occur at any point from farm to table, as a result of improper hygiene, handling, storage or preparation, and the broad range of food products that can be contaminated adds to the complexity. An estimated 652,000 cases of infectious diseases because of contaminated food occurred in 2018 in the Netherlands, leading to around EUR 171 million in costs [4]. This figure and corresponding costs have remained at the same level since 2009 [4,5]. The exact number of cases remains unknown; only a minority of food-borne cases is captured by surveillance systems since most infections are relatively mild and no diagnostic testing is performed. Furthermore, not all food-borne infections are systematically monitored.

Although recognised food-borne outbreaks only account for a small part of the food-borne disease burden, they can provide insight into the pathogens causing outbreaks, food products implied as vehicles, points of contamination, and settings in which transmission occurs [6,7]. Determination of the contaminated food product is difficult, especially in sporadic cases, because of varying incubation periods in which many exposures occurred, as well as recall bias. Outbreaks offer the opportunity to gather consumption data from more than one case and to perform a comparison with controls, which increases the chance of finding the contaminated food item. Analysis of data over a longer period also offers the opportunity to describe trends in food-borne outbreaks, to identify new and emerging food-borne pathogens and specific pathogen-food combinations, and to examine the public health importance of pathogens, which can be used to improve food safety [6,8].

The aim of this study is to describe the characteristics of food-borne outbreaks registered between 2006 and 2019 in the Netherlands in order to provide a better understanding of food-borne outbreaks and to guide efforts to control, reduce and prevent future food-borne illness.

UK – Estimating deaths from foodborne disease in the UK for 11 key pathogens

NCBI

Objective

To estimate the number of deaths from foodborne disease in the UK from 11 key pathogens.

Design

Four different models were developed using data from a range of sources. These included enhanced surveillance, outbreaks, death certificates and hospital episode statistics data. For each model, median estimates were produced with 95% credible intervals (CrI). The results from the different models were compared.

Results

The estimates for foodborne deaths for each pathogen from the different models were consistent, with CrIs largely overlapping. Based on the preferred model for each pathogen, foodborne norovirus is estimated to cause 56 deaths per year (95% CrI 32 to 92), foodborne Salmonella 33 deaths (95% CrI 7 to 159), foodborne Listeria monocytogenes 26 deaths (95% CrI 24 to 28), foodborne Clostridium perfringens 25 deaths (95% CrI 1 to 163) and foodborne Campylobacter 21 deaths (95% CrI 8 to 47). The considerable overlap in the CrIs means it is not possible to make any firm conclusions on ranking. Most of these deaths occur in those aged over 75 years. Foodborne deaths from ShigellaCryptosporidiumGiardia, adenovirus, astrovirus and rotavirus are all rare.

Conclusions

We estimate that there are 180 deaths per year in the UK (95% CrI 113 to 359) caused by foodborne disease based on these 11 pathogens. While this is a small fraction of the estimated 2.4 million cases of foodborne illness per year it still illustrates the potential severity of these illnesses demonstrating the importance in continuing efforts to reduce these infections.

Keywords: infectious disease, CampylobacterSalmonella

Summary box

What is already known about this subject?

  • Foodborne disease is a common illness in the UK.

  • Previous research has estimated that there are 566 000 cases, 74 000 general practitioner presentations and 7600 hospital admissions related to foodborne disease from 13 known pathogens in UK; no estimate was made for deaths.

  • Campylobacter and norovirus are the most common foodborne pathogens in the UK.

  • Other common foodborne pathogens include Clostridium perfringens and Salmonella.

What are the new findings?

  • This study provides updated estimates of deaths for each of the 11 key foodborne pathogens considered; in total, these 11 pathogens cause 180 deaths per year in the UK (95% credible interval (CrI) 113 to 359).

  • Among them, Campylobacter, C. perfringens, Listeria monocytogenes, Salmonella and norovirus pathogens are responsible for over 98% of these deaths.

  • Ranking between these five is difficult due to overlapping CrIs.

How might it impact on clinical practice in the foreseeable future?

  • This highlights the potential severity of Salmonella, L. monocytogenesC. perfringensCampylobacter and norovirus, particularly in comparison with other infectious intestinal diseases that have a food source.

CPS – Funded Projects 2022 – Superheated Steam – Process Surface Decontamination

CPS

Practical application of superheated steam to harvesting, processing, and produce packing tools and equipment

Pathogens can contaminate environmental surfaces in produce handling operations. The industry uses sanitation programs to clean these surfaces and prevent product contamination. Highly effective sanitation procedures reduce the likelihood that pathogens will cross-contaminate products. In facilities that do not use water in their sanitation programs, tools like brushes and rags are used to clean. No-rinse sanitizers are sometimes used as well, but they cannot be used in organic operations. Superheated steam is a novel surface sanitizer that can kill pathogens on environmental surfaces. It is sometimes referred to as “dry steam” because it does not leave moisture or condensation on surfaces, making it a viable option for dry produce facilities. This project is designed to evaluate superheated steam use under industry relevant conditions. We will not only determine how well it works, but we will assess other key performance indicators including cost, range of appropriate applications, and the effect of extended use on equipment wear-and-tear and change to ambient relative humidity. This project will provide industry with the tools to comprehensively assess tradeoffs in superheated steam implementation. These resources will help improve the design of sanitation programs and enhance control over pathogen cross-contamination.

Research – Best Practice for the Control of Human Pathogenic Microorganisms in Plant Production Systems

Teagasc

There is an increased emphasis on and observance of food-borne diseases associated with fresh produce, due in part to changes in the processing, agronomy and distribution of fresh produce but also in the increasing trend for the consumption of minimally processed and raw, ready-to-eat crops. A recent meeting of European experts and commercial growers, assembled under the HuPlant Cost Action assessed the current European situation in relation to the safety of horticultural produce under the themes of
(1) protecting fresh produce from microbial pathogens,
(2) control strategies and sampling and
(3) risk assessment and risk based sampling.
The following report details the discussions and observations which emanated from that meeting, including a list of recommendations, aimed at
(1) Growers,
(2) Regulators and Advisors and
(3) Scientists.
For growers recommendations include reinforcement through clear communication on the need to prevent initial contamination of produce through the adoption of good microbiological safety practice, utilising on farm risk assessments and a focus on avoidance of initial contamination rather than a reliance on decontamination efforts.
This can be achieved through approaches such as the adoption and incorporation of good agricultural practice and good hygiene into standard operating procedures on farm. Recommendations to regulators and advisors include balancing communication messages to growers, indicating what is required of them, but also equally, clearly explaining why it is necessary.
Additionally it was felt that additional supports and materials could be made available to growers, particularly to smaller growers, to assist in the training of staff on the importance of biological safety practice, particularly in sectors where staff turnover may be high and differences in the native languages spoken.
Finally recommendations to scientists include a greater emphasis on knowledge transfer and also to, where possible focus knowledge transfer efforts into developing clear recommendations which growers can implement. The interaction between the plant microbiome, potential pathogens, environmental conditions and agricultural practices requires a greater level of attention and research to aid in predict the risk of human pathogen establishment.
Overall it was recognised that through increased interaction and information exchange between stakeholders will enable better understanding of the issues and opportunities faced by the horticultural sector and the co-creation of advice through participation of all stakeholders can assist in reducing the risk of contamination of horticultural produce.

Research – Detrimental Effect of Ozone on Pathogenic Bacteria

MDPI

Background: Disinfection of medical devices designed for clinical use associated or not with the growing area of tissue engineering is an urgent need. However, traditional disinfection methods are not always suitable for some biomaterials, especially those sensitive to chemical, thermal, or radiation. Therefore, the objective of this study was to evaluate the minimal concentration of ozone gas (O3) necessary to control and kill a set of sensitive or multi-resistant Gram-positive and Gram-negative bacteria. The cell viability, membrane permeability, and the levels of reactive intracellular oxygen (ROS) species were also investigated;

Material and Methods: Four standard strains and a clinical MDR strain were exposed to low doses of ozone at different concentrations and times. Bacterial inactivation (cultivability, membrane damage) was investigated using colony counts, resazurin as a metabolic indicator, and propidium iodide (PI). A fluorescent probe (H2DCFDA) was used for the ROS analyses;

Results: No reduction in the count colony was detected after O3 exposure compared to the control group. However, the cell viability of E. coli (30%), P. aeruginosa (25%), and A. baumannii (15%) was reduced considerably. The bacterial membrane of all strains was not affected by O3 but presented a significant increase of ROS in E. coli (90 ± 14%), P. aeruginosa (62.5 ± 19%), and A. baumanni (52.6 ± 5%);

Conclusion: Low doses of ozone were able to interfere in the cell viability of most strains studied, and although it does not cause damage to the bacterial membrane, increased levels of reactive ROS are responsible for causing a detrimental effect in the lipids, proteins, and DNA metabolism. View Full-Text

Research – Super bugs bedevil food safety

Food Safety News

“Super bugs” and “food safety.” You can say the two in one breath simply because they are so closely connected.

“Super bugs” is a popularized term for “antibiotic resistance,” or “antimicrobial resistance.” They don’t go by that name for nothing. According to the federal Centers for Disease Control and Prevention, each year in the United States, at least 2.8 million people are infected with antibiotic-resistant bacteria or fungi. More than 35,000 people die as a result. Antibiotic resistant bacteria frequently show up in outbreak strains of pathogens such as E. Coli, Salmonella and Listeria monocytogenes.

When looking ahead, the picture only gets more daunting. Some medical experts predict that worldwide by 2050 the number of deaths attributed to antibiotic resistance could reach 10 million and cost trillions of dollars — unless collective action is taken on a global scale.

No wonder then that some human and animal health experts are referring to this as a “slow moving pandemic.”

Research – Differential Survival of Generic E. coli and Listeria spp. in Northeastern U.S. Soils Amended with Dairy Manure Compost, Poultry Litter Compost, and Heat-Treated Poultry Pellets and Fate in Raw Edible Radish Crops

Journal of Food Protection

Composted or heat-treated Biological Soil Amendments of Animal Origin (BSAAO) can be added to soils to provide nutrients for fresh produce. These products lower the risk of pathogen contamination of fresh produce when compared with use of untreated BSAAO; however, meteorological conditions, geographic location, and soil properties can influence the presence of pathogenic bacteria, or their indicators (e.g., generic E. coli) and allow potential for produce contamination. Replicated field plots of loamy or sandy soils were tilled and amended with dairy manure compost (DMC), poultry litter compost (PLC), or no compost (NoC) over two different field seasons, and non-composted heat-treated poultry pellets (HTPP) during the second field season. Plots were inoculated with a three-strain cocktail of rifampicin-resistant E. coli (rE.coli) at levels of 8.7 log CFU/m2. Direct plating and most probable number (MPN) methods measured the persistence of rE.coli and Listeria spp. in plots through 104 days post-inoculation. Greater survival of rE. coli was observed in PLC plots in comparison to DMC plots and NoC plots during year 1 (P < 0.05). Similar trends were observed for year 2, where rE. coli survival was also greater in HTPP amended plots (P < 0.05). Survival of rE. coli was dependent on soil type, where water potential and temperature were significant covariables. Listeria spp. were found in NoC plots, but not in plots amended with HTPP, PLC or DMC. Radish data demonstrate that PLC treatment promoted the greatest level of rE.coli translocation when compared to DMC and NoC treatments (P  < 0.05). These results are consistent with findings from studies conducted in other regions of the US and informs Northeast produce growers that composted and non-composted poultry-based BSAAO supports greater survival of rE. coli in field soils. This result has the potential to impact the food safety risk of edible produce grown in BSAAO amended soils as a result of pathogen contamination.

Research – How Safe to Eat Are Raw Bivalves? Host Pathogenic and Public Health Concern Microbes within Mussels, Oysters, and Clams in Greek Markets

MDPI

Raw-bivalves consumption is a wide trend in Mediterranean countries. Despite the unambiguous nutritional value of seafood, raw consumption of bivalves may involve risks that could pose a significant threat to consumers’ health. Their filter-feeding behavior is responsible for the potential hosting of a wide variety of microorganisms, either pathogenic for the bivalves or public health threats. Under this prism, the current study was conducted in an effort to evaluate the risk of eating raw bivalves originating from the two biggest seafood markets in Thessaloniki, the largest production area of bivalves in Greece. Both microbiological and molecular methodologies were applied in order to assess the presence of various harmful microbes, including noroviruses, BonamiaMarteiliaEsherichia coliSalmonella, and Vibrio. Results indicated the presence of several Vibrio strains in the analyzed samples, of which the halophilic Vibrio harveyi was verified by 16S rRNA sequencing; other than this, no enteropathogenic Vibrio spp. was detected. Furthermore, although Esherichia coli was detected in several samples, it was mostly below the European Union (EU) legislation thresholds. Interestingly, the non-target Photobacterium damselae was also detected, which is associated with both wound infections in human and aquatic animals. Regarding host pathogenic microorganisms, apart from Vibrio harveyi, the protozoan parasite Marteilia refrigens was identified in oysters, highlighting the continuous infection of this bivalve in Greece. In conclusion, bivalves can be generally characterized as a safe-to-eat raw food, hosting more bivalve pathogenic microbes than those of public health concern.

Research – The Persistence of Bacterial Pathogens in Surface Water and Its Impact on Global Food Safety

MDPI

Water is vital to agriculture. It is essential that the water used for the production of fresh produce commodities be safe. Microbial pathogens are able to survive for extended periods of time in water. It is critical to understand their biology and ecology in this ecosystem in order to develop better mitigation strategies for farmers who grow these food crops. In this review the prevalence, persistence and ecology of four major foodborne pathogens, Shiga toxin-producing Escherichia coli (STEC), SalmonellaCampylobacter and closely related Arcobacter, and Listeria monocytogenes, in water are discussed. These pathogens have been linked to fresh produce outbreaks, some with devastating consequences, where, in a few cases, the contamination event has been traced to water used for crop production or post-harvest activities. In addition, antimicrobial resistance, methods improvements, including the role of genomics in aiding in the understanding of these pathogens, are discussed. Finally, global initiatives to improve our knowledge base of these pathogens around the world are touched upon.

Research – Risk evaluation of E. coli ST 131 as a foodborne pathogen in Switzerland

BLV

Within recent years, the topic of multidrug-resistant, uropathogenic Escherichia coli strains has seen a rise in occurrence as foodborne pathogens. At the core of this topic is the specific clonal group referred to as Escherichia coli O25b:H4 sequence type 131 (ST 131). It is an extended-spectrum β-lactamase (ESBL) producing E. coli strain, postulated to be responsible for the spread of ESBL-encoding genes world-wide.
This literature review aimed to evaluate ST 131 as a foodborne pathogen in Switzerland, in order to assess the risk it poses for food producers in Switzerland specifically. On a global scale, ST 131 has been identified on all continents. It is mostly associated with chicken and poultry meat, and has been isolated from retail products many times.
Not exclusive to chicken, it was rarely identified from fish guts and gills. In all other meat products, ST 131 was found only in faecal matter, not in the product itself. Besides meat, the pathogen was not identified from any sources such as dairy, fruit and vegetables.
The situation is similar in Switzerland, where it was isolated frequently from chicken, rarely from fish and a complete absence of the pathogen in all other food product groups. The risk, ST 131 poses towards Swiss food producers has been evaluated as a medium risk factor for both chicken and fish products, and a low risk factor for any other products. Despite ST 131 being evaluated as a medium-to-low risk factor, depending on the product, it is still recommended to perform further research on the topic. Especially looking towards prevalence in Swiss food, in chicken and poultry meat, but also in fish.
Specifically fish designated for raw consumption (Sushi, Sashimi). Moreover, the spread of afore-mentioned ESBL-encoding genes is hypothesized to occur also during infection of humans. This leads to the recommendation, that ST 131 should be considered a food-safety risk in all products, in order to eliminate said spread. Whether this consideration as a food-safety risk is feasible, cannot be said without further analysis of products and viable treatment options.