Category Archives: Food Microbiology Research

UK – AMR in Campylobacter in UK chicken over the last 20 years

FSA

Campylobacter kswfoodworld

The Food Standards Agency (FSA) has published a report analysing 20 years of data on antimicrobial resistance (AMR) in Campylobacter from retail chicken in the UK.

The study aimed to assess any trends during this 20-year period and provides a baseline against which to evaluate future, hoped-for reductions in AMR.

AMR is when bacteria adapt to become resistant to the killing effects of antimicrobials, such as antibiotics. This resistance subsequently makes such infections in humans more difficult to treat using drugs.  AMR can develop in any bacteria, including Campylobacter. Campylobacter is the main cause of bacterial food poisoning in the developed world and it is estimated that there are in excess of half a million cases annually in the UK.

The FSA’s Science lead in Microbiological Risk Assessment, Dr Paul Cook, said:

“While the data shows a marked increase in AMR in Campylobacter to certain antimicrobials, it is encouraging that there has been no significant increase in resistance since 2014.

“Any increase of AMR in Campylobacter is a concern and continued surveillance is essential. We will continue to carry out AMR surveillance in chicken and other meats and to monitor any long-term trends in resistance, while promoting good food hygiene practice to reduce exposure to AMR bacteria and protect consumer safety.”

Since its formation in 2000, the FSA has commissioned several UK-wide retail surveys and sampling studies that involved testing for Campylobacter in chicken. A significant proportion of the Campylobacter isolates detected were further tested to assess resistance to a range of antimicrobials.

Key findings from this report vary between the five main types of antimicrobial drugs included in the study. Resistance to quinolones (ciprofloxacin and nalidixic acid) and tetracycline was common in the most prevalent types of Campylobacter from chicken (Campylobacter jejuni and Campylobacter coli). In comparison, resistance to erythromycin and streptomycin was much rarer in the Campylobacter isolates examined.  Gentamicin resistance was very rare.

There are effective ways for consumers to reduce exposure to AMR bacteria. This includes cleaning surfaces properly, cooking food thoroughly, chilling food at the correct temperature and handling food hygienically so it doesn’t cross contaminate other foods or surfaces. For any fruit or vegetables consumed raw, make sure they are washed thoroughly or peeled as this will help to remove any visible dirt or bacterial contamination.

For more information on AMR, including an ‘FSA Explains’ video, visit our dedicated AMR webpage. The research report is available on our research pages.

Research – Fighting Foodborne Pathogens with Natural Antimicrobials

Mirage News

The food industry has now started exploring natural alternatives for preserving food to reduce the dependency on chemical preservatives, some of which are linked to obesity and metabolic syndrome. Specifically, natural antimicrobials produced by plants and microorganisms like bacteria and fungi can kill food-borne pathogens like Salmonella Typhimurium, Escherichia coliListeria monocytogenes and Clostridium botulinum and also food spoilage bacteria like Brochothrix thermosphactaLactobacillus spp., Bacillus spp. and Weissella spp., among others. Foodborne pathogens and spoilage microbes pose a serious health concern for consumers and destroy the appearance, texture and sensory characteristics of the food, affecting the food industry and consumers alike.

USA – 60 Potential Illnesses Linked to a Salmonella Outbreak in Spring Branch County – Possibly from an Event at Lost Mission?

Food Poisoning News

According to one victim in what is alleged to be an outbreak of 60+ patrons, a food poisoning outbreak (she contracted salmonella) is currently being investigated by the Bexar/Comal County Health Departments in Texas. According to one source, multiple food items were served, including Whataburger and cake, among other things.   The victim who has come forward, Sarah Castillo, however, ate chicken piccata, a Caesar salad, angel hair pasta, and green beans. According to Ms. Castillo, she began experiencing symptoms of salmonella shortly after attending a wedding at a local, and very popular, venue called Lost Mission.  Lost Mission is located in Spring Branch Texas.

The beautiful wedding, unfortunately, turned into a dismal affair for Ms. Castillo after she became ill with the symptoms and side-effects of salmonellosis. She was compelled to seek medical treatment from the Texas MedClinic Urgent Care, and then when her condition deteriorated, University Hospital in San Antonio.

USA – D.C. Cobb’s linked to illness outbreak

Food Poison Journal

The McHenry County Department of Health has closed its illness outbreak survey linked to D.C. Cobb’s, 1204 N. Green Street in McHenry, and is continuing its gastrointestinal illness outbreak investigation.

After sharing the illness outbreak investigation survey on Tuesday, MCDH received 508 completed survey responses. MCDH would like to thank everyone who completed the survey for their assistance in the investigation.

The data collected from the survey and individual interviews is being analyzed to determine the scope and cause of the outbreak including whether any food items are the likely source of the illness and to identify other risk factors that contributed to the spread. Stool specimens are being collected from ill individuals to be tested to identify the type of pathogen that led to the illness.

MCDH staff is conducting a food analysis using the data collected from the survey. The food analysis involves looking at the foods that ill and well individuals ate to determine the likelihood that someone became ill after eating a particular food item. It is not always possible to determine a single food item during an outbreak investigation. This can happen if multiple food items led to the spread of illness or if there is not enough information to determine the cause of illness.

Research – Evaluation of the Impact of Compliance with Mitigation Strategies and Frequency of Restaurant Surface Cleaning and Sanitizing on Control of Norovirus Transmission from Ill Food Employees Using an Existing Quantitative Risk Assessment Model 

Journal of Food Protection

Norwalk_Caspid

ABSTRACT

Reduction of foodborne illness caused by norovirus (NoV) continues to be a focus for the food safety community. Using a previously published quantitative risk assessment model, we evaluated more than 60 scenarios examining the impact of implementation of and compliance with risk management strategies identified in the U.S. Food and Drug Administration Food Code for (a) surface cleaning and sanitizing, (b) hand hygiene, (c) exclusion, or (d) restriction of ill employees. Implementation of and compliance with hand hygiene and ill food employee exclusion strategies had the largest impact on the predicted number of highly contaminated food servings and associated consumer illnesses. In scenarios in which gloves were always worn and hand washing compliance was 90%, the model estimated reductions in the number of highly contaminated food servings and ill consumers to 39 and 43% of baseline estimates (i.e., typical practice), respectively. Reductions were smaller when gloves were never worn. Hand washing compliance after using the restroom strongly impacted predicted numbers of highly contaminated servings and consumer illnesses. Ten percent compliance with removing or excluding ill food employees was predicted to increase the number of highly contaminated food servings and ill consumers to 221 and 213% of baseline estimates, respectively. Ninety-four percent compliance with exclusion of ill food employees was predicted to decrease these numbers to 69 and 71% of baseline estimates, respectively. Surface cleaning in food establishments had a relatively small impact on these measures. Restriction of food employees (removed from contact with food and food contact equipment and utensils) was not effective for reducing NoV illness unless this restriction included additional provisions. The results from this study can help risk managers prioritize mitigation strategies and their implementation for controlling the transmission of NoV and subsequent consumer foodborne illness.

HIGHLIGHTS
  • We adapted a discrete event NoV transmission model for use in a food establishment.
  • Compliance with exclusion and hand hygiene rules had the most impact on consumer illnesses.
  • Washing hands before donning and changing gloves efficiently reduces NoV transfer.
  • Restriction of food employees needs additional provisions to be effective.
  • Surface cleaning and sanitizing has the least impact on consumer illnesses.

Research – Inhibitory Effect against Listeria monocytogenes of Carbon Nanoparticles Loaded with Copper as Precursors of Food Active Packaging

MDPI

Human listeriosis is a serious foodborne disease of which outbreaks are occurring increasingly frequently in Europe. Around the world, different legal requirements exist to guarantee food safety. Nanomaterials are increasingly used in the food industry as inhibitors of pathogens, and carbon nanomaterials are among the most promising. In the present study, novel carbon nanoparticles loaded with copper (CNP-Cu) were prepared, and their antimicrobial activity against Listeria monocytogenes was assessed. CNPs of two sizes were synthesized and characterized by dynamic light scattering (DLS), electrophoretic light scattering (ELS) and electron microscopy (EM). The minimum inhibitory concentration (MIC) of CNP-Cu was determined in accordance with the available standard. To get insights into its mechanism of action, the release of copper ions into a cell media was assessed by inductively coupled plasma optical emission (ICP-OE), and the ability of loaded CNPs to generate cytotoxic reactive oxygen species (ROS) was evaluated by EPR spectroscopy. Finally, the extent of release of copper in a food simulant was assessed. The results demonstrated the antimicrobial effectiveness of CNP-Cu, with growth inhibition up to 85% and a release of copper that was more pronounced in an acidic food simulant. Overall, the results indicate CNP-Cu as a promising agent for the design of active food packaging which is able to improve food shelf-life.

Research – Toxoplasma gondii Antibodies in Raw Milk and Sera of Cows in China

MDPI

Toxoplasma gondii is a worldwide food-borne protozoa that has harmful influences on animal and human health. Raw milk containing T. gondii has been considered as one of the possible infectious sources for humans. Although China is one of the world’s leading milk consumers, there is still no study to investigate the seroprevalence of T. gondii in raw cow milk in China; especially for cows in rural areas. Thus, we conducted this study to examine the specific anti-T. gondii IgG-antibody in the raw milk and sera of domestic cows in China. In total, 894 cows were randomly selected from rural areas in northeastern China. The positive rate of T. gondii in the milk and serum samples were 6.38% (57/894) and 7.16% (64/894), respectively. Moreover, a history of abortion (OR = 2.03, 95% CI: 1.11–3.72, p = 0.022) was identified as the only risk factor for T. gondii infection in the studied cows. This study investigated the seroprevalence of T. gondii in the raw milk and sera of cows in China; it provided timely and useful data for public health and food safety, especially in rural areas. View Full-Text

Research – Project seeks to grow knowledge of Listeria in dairy sites

Food Safety News

An ongoing project is identifying the bacteria present in dairy processing environments to evaluate the impact on Listeria monocytogenes.

Teagasc in Ireland and the University of Veterinary Medicine Vienna in Austria are collecting samples from dairy processing plants and characterizing the microorganisms, with the aim being to prevent the presence of harmful pathogens.

The LmRNA project is gaining an understanding of Listeria monocytogenes’ response to dairy environment conditions. Mock communities of microorganisms are being created in the laboratory to mimic what is found in dairy environments. The role of other microorganisms is being investigated to determine their impact on Listeria monocytogenes.

A food processing environment is not sterile and the presence of some microorganisms in cheese production can be desired. During dairy processing, milk components may adsorb to surfaces enhancing attachment and biofilm formation.

Research – Sources and trends of human salmonellosis in Europe, 2015–2019: An analysis of outbreak data

Science Direct

Highlights

Salmonella outbreaks in Europe provide a picture of the most important sources at exposure level.

Relative importance of different food sources by year, European region and serotype is determined.

Eggs continue to be the most important food source of salmonellosis outbreaks in Europe.

Reported Salmonella outbreaks increased significantly in Eastern European countries.

Abstract

Salmonella remains a major cause of foodborne outbreaks in Europe despite the implementation of harmonized control programmes. Outbreak data are observed at the public health endpoint and provide a picture of the most important sources of human salmonellosis at the level of exposure. To prioritize interventions, it is important to keep abreast of the sources and trends of salmonellosis outbreaks. The objective of this study was to determine the main food sources and recent trends of Salmonella outbreaks in Europe. Salmonella outbreak data from 34 European countries in 2015–2019 were obtained from the European Food Safety Authority (EFSA). For the source attribution analysis, implicated foods were categorized according to EFSA’s zoonosis catalogue classification scheme. An established probabilistic source attribution model was applied using the information on the implicated foods, overall and by region and serotype. To assess significant trends in outbreak occurrence, overall and by region and serotype, mixed-effects Poisson models were used. Overall, the most important food source of salmonellosis outbreaks was eggs (33 %, 95 % Uncertainty Interval [UI]: 31–36 %), followed by pork (7 %, 95 % UI: 6–8 %), and (general) meat products (6 %, 95 % UI: 5–8 %). While eggs were the most important food source in all regions, pork was the second most common food source in Northern and Western Europe, and (general) meat products in Eastern and Southern Europe. Outbreaks caused by S. Enteritidis (SE) and other known serotypes (other than SE and S. Typhimurium and its monophasic variant [STM]) were mostly attributed to eggs (37 %, 95 % UI: 34–41 % and 17 %, 95 % UI: 11–25 %, respectively), whereas outbreaks caused by STM were mainly attributed to pork (34 %, 95 % UI: 27–42 %). Overall, there was a significant increase in the number of outbreaks reported between 2015 and 2019, by 5 % on average per year (Incidence Rate Ratio [IRR]: 1.05, 95 % Confidence Interval [CI]: 1.01–1.09). This was driven by a significantly increased number of outbreaks in Eastern Europe, particularly those caused by SE (IRR: 1.15, 95 % CI: 1.09–1.22), whereas in Northern and Southern Europe, outbreaks caused by SE decreased significantly from 2015 to 2019 (IRR: 0.72, 95 % CI: 0.61–0.85; IRR: 0.70, 95 % CI: 0.62–0.79, respectively). Regional, temporal and serotype-associated differences in the relative contributions of the different sources were also observed.

Research – Listeria monocytogenes survives better at lower storage temperatures in regular and low-salt soft and cured cheeses

Science Direct

Highlights

Salt reduction did not affect the behaviour of Listeria monocytogenes in soft cheeses.

The pathogen showed greater survival capacity at 4 °C than at 22 °C in both types of cheeses.

The prevalence of the serovar 1/2c strain increased over storage time in soft cheeses.

Abstract

The behaviour of Listeria monocytogenes was investigated in soft pasteurized milk cheese elaborated with different salt concentrations (1.17 and 0.30% w/w) and in cured raw sheep milk cheese over storage up to 189 days at different isothermal conditions. Commercial 25-g cheese samples were inoculated with a 4-strain cocktail of L. monocytogenes (serovars 4b, 1/2a, 1/2b and 1/2c) at approximately 104 CFU/g. The inoculated samples were stored at 4 and 22 °C and withdrawn at proper intervals for L. monocytogenes enumeration. The prevalence of the different serovar strains of L. monocytogenes was characterized on soft cheese samples over storage at 4 °C using multiplex PCR. Salt reduction did not affect the survival of L. monocytogenes in soft cheeses and a maximum of 1-log reduction was observed in both regular and low-salt cheeses after 189 days of storage at 4 °C. The pathogen showed greater survival capacity in both soft and cured cheeses during storage at 4 °C compared to the storage at 22 °C, where more than 2.5 log reductions were computed. The fate of L. monocytogenes was described through a Weibull model fitted to survival data. The time required for a first tenfold reduction of the L. monocytogenes population (δ) at 4 °C is around 150 days in soft and 72 days in cured cheeses. At 22 °C, the estimated δ values are at least 60% lower in both cheese types. Among the four L. monocytogenes serovars present in the inoculated cocktail, the serovar 4b strain was the most sensitive to refrigerated storage, while the prevalence of serovar 1/2c strain increased over time in soft cheeses. Overall, the data obtained in this study help to deepen knowledge into factors affecting L. monocytogenes behaviour on cheeses and evidenced the variability between serovars in terms of survival capacity, which may be considered when performing microbial risk assessments.