Category Archives: Research

Research – Microbiologists get grant to study biofilms guarding foodborne pathogen Listeria

Mirage News

Microbiologists in Penn State’s College of Agricultural Sciences have received a $605,000 grant from the U.S. Department of Agriculture to study how microbial biofilms protect Listeria monocytogenes, the bacterium that causes the deadly foodborne illness listeriosis.

Jasna Kovac, Lester Earl and Veronica Casida Career Development Professor of Food Safety, along with Luke LaBorde, professor of food science, will use the funding from USDA’s National Institute of Food and Agriculture to conduct research on the interactions between microorganisms found in fruit-packing environments and Listeria monocytogenes.

“We will study the ability of environmental microorganisms to form robust biofilms together with L. monocytogenes and how these biofilms may protect L. monocytogenes from the antimicrobial activity of sanitizers,” said Kovac, assistant professor of food science. “The data generated in this project will help improve the cleaning and sanitizing used in the fresh produce industry to better control L. monocytogenes and support the production of safe food.”

Listeria and other microorganisms found in the natural environment, such as soil, can be introduced unintentionally into food-processing facilities with raw foods such as fruit. The research is needed, Kovac explained, because once introduced into the food-processing environment, Listeria and many other environmental microorganisms can grow on surfaces into microbial layers called biofilms.

“Microorganisms enclosed in a biofilm produce slimy substances that protect them from the antimicrobial activity of sanitizing chemicals by slowing down their penetration into the core of a biofilm,” Kovac said. “Biofilm formation can therefore result in reduced efficacy of antimicrobial sanitizers used to inactivate Listeria. This project will investigate the interactions between microorganisms found in fruit-packing environments and L. monocytogenes.”

Research – Determination of Listeria monocytogenes, competitive microflora, microbial hygiene indicators and physico-chemical parameters during the shelf-life of the typical Mediterranean style fermented sausage “Salsiccia Sarda”

Journal of Food Protection

The aim of the present study was the determination of Listeria monocytogenes , competitive microbiota, microbial hygiene indicators and physico-chemical parameters in the typical Mediterranean Style fermented sausages “Salsiccia Sarda” . A batch of “Salsiccia Sarda” (25 samples) naturally contaminated by L. monocytogenes and vacuum packaged after 24 days of ripening was included in the study. Fifteen samples stored at 8° C were analysed after 13, 90 and lastly at the end of shelf-life, after 180 days from vacuum packaging. Ten vacuum packaged samples were stored at 12°C in a domestic fridge simulating temperature abuse and were evaluated at the end of the shelf-life. Samples were subjected to physico-chemical analysis (pH and aw) and investigated for the presence and enumeration of L. monocytogenes . Competitive microbiota, Lactic Acid Bacteria (LAB) and Coagulase negative Staphylococci (CNS), and microbial hygiene indicators (Total mesophilic bacterial counts, Enterobacteriaceae, Enterococcuss spp. and Staphylococcus aureus ) were determined in all the samples. Although a decreasing trend in L. monocytogenes prevalence was observed through the shelf-life, the detection of the pathogen in fermented sausages confirms the ability of L. monocytogenes to overcome the hurdles of the manufacturing process. The results of the present study highlight the importance to carefully evaluate the “Salsiccia Sarda” production process by Food Business Operators (FBOs) in order to maintain unfavourable conditions for the growth of L. monocytogenes .

Research – Prevalence and levels of Campylobacter in broiler chicken batches and carcasses in Ireland in 2017–2018

Science Direct

Highlights

Provides valuable qualitative and quantitative data on Campylobacter in Irish Broilers.

Study demonstrates improvements and progress made in the Irish poultry industry.

Study provides indications of several factors on Campylobacter contamination rates.

Abstract

In 2008, an EU wide baseline survey of broilers revealed a high Campylobacter prevalence. To assist with industry-wide controls, updated data were required. The primary objective of this study was to establish up-to-date data on Campylobacter carriage and carcass contamination in Irish broilers. Monthly samples were collected from the three largest broiler processing plants in Ireland over a twelve-month period. Samples were taken from both first and final thin birds (partial and full depopulation) from 358 batches of broilers. From each batch, a composite sample of 10 caecal contents (n = 358) and 5 neck skins (n = 1790) were collected and numbers of Campylobacter in each sample were determined. Of the 1790 neck skin samples tested, 53% were Campylobacter positive. Campylobacter was detected in the caecal contents of 66% of all batches tested. Depopulation and/or age had a significant effect on Campylobacter prevalence with 67% of final thin broilers yielding Campylobacter-positive neck skin samples in contrast to 38% of first thin broilers that yielded positive neck skin samples (P ≤ 0.002). A significant seasonal variation was observed in the rate of Campylobacter-positive caecal samples with higher prevalence seen in July (85%) than the colder months of November (61%), December (50%), January (61%) March (57%) and April (59%). Neck skin samples were 7 times more likely to be Campylobacter positive if the caecal contents from the same batch were positive (odds ratio = 7.1; P ≤ 0.0001). The decrease in Campylobacter prevalence observed in neck skin and caecal contents demonstrates the improvements and progress made in reducing prevalences of this important enteropathogen in the Irish poultry industry since the 2008 EU baseline survey. It also provides further supporting data on the impact of thinning, the processing environment and season on Campylobacter prevalence.

Research – Invasive listeriosis outbreaks and salmon products: a genomic, epidemiological study

Tandfonline

Invasive listeriosis, caused by Listeria (L.) monocytogenes, is a severe foodborne infection, especially for immunocompromised individuals. The aim of our investigation was the identification and analysis of listeriosis outbreaks in Germany with smoked and graved salmon products as the most likely source of infection using whole-genome sequencing (WGS) and patient interviews.

In a national surveillance program, WGS was used for subtyping and core genome multi locus sequence typing (cgMLST) for cluster detection of L. monocytogenes isolates from listeriosis cases as well as food and environmental samples in Germany. Patient interviews were conducted to complement the molecular typing.

We identified 22 independent listeriosis outbreaks occurring between 2010 and 2021 that were most likely associated with the consumption of smoked and graved salmon products. In Germany, 228 cases were identified, of 50 deaths reported (22%) 17 were confirmed to have died from listeriosis. Many of these 22 outbreaks were cross-border outbreaks with further cases in other countries.

This report shows that smoked and graved salmon products contaminated with L. monocytogenes pose a serious risk for listeriosis infection in Germany. Interdisciplinary efforts including WGS and epidemiological investigations were essential to identifying the source of infection. Uncooked salmon products are high risk foods frequently contaminated with L. monocytogenes. In order to minimise the risk of infection for consumers, food producers need to improve hygiene measures and reduce the entry of pathogens into food processing. Furthermore, susceptible individuals should be better informed of the risk of acquiring listeriosis from consuming smoked and graved salmon products’.

Research – Will climate change increase the risk of aflatoxin in U.S. corn?

Science Daily

As climate change continues to alter weather patterns around the planet including the Midwest, researchers at Michigan State University are modeling the impact on crops such as corn.

“The United States is the largest exporter and donor of field corn around the world,” said Felicia Wu, a John A. Hannah Distinguished Professor and an international expert on food safety in the Department of Food Science and Human Nutrition and the Department of Agricultural, Food, and Resource Economics in the College of Agriculture and Natural Resources at MSU. “Here in the U.S., we consume field corn in the form of corn chips, corn flakes, corn grits and corn tortillas; as opposed to sweet corn, which is frozen, canned and eaten off the cob. Field corn is also used for animal feed and for ethanol production.”

The fungi Aspergillus flavus and Aspergillus parasiticus produce aflatoxin which can infect peanuts, tree nuts and corn. Aflatoxin not only degrades corn quality but can also cause health problems for humans and animals depending on the amount and length of time it is ingested. While aflatoxin contamination occurs annually in the southern United States because of the hot and dry climate, it has rarely been a serious problem in the Corn Belt region of the U.S.

“When we ran our near-term climate model scenarios, we found that between 2031-2040, aflatoxin is going to become more of a problem in the U.S. Corn Belt in the Midwest,” Wu said. “The last time there was a serious problem was in 2012 when we had an unusually hot and dry summer throughout the Midwest; particularly Iowa, Illinois and Indiana.”

Wu’s research was published April 5, 2022 in the journal Environmental Research Letters. Co-authors on the paper include her former doctoral student Jina Yu (Hong Kong Baptist University), David Hennessy (Iowa State University) and Jesse Tack (Kansas State University).

Hot and dry conditions encourage fungi spores to be airborne which increases their chances of contaminating crops. Water helps plants withstand stress that makes them vulnerable to harmful fungi. Steps growers, grain elevators and processors can take to reduce the risk of aflatoxin contamination include storing corn harvests in cool, dry conditions and keeping crops irrigated to the extent possible given declining water tables.

Researchers are already using both biotechnological and conventional breeding techniques to develop hybrid crops that can withstand drought, insect damage and fungal infections. In many parts of the world, corn growers are using biocontrol to reduce aflatoxin. Biocontrol infects plants with Aspergillus fungi which is unable to produce aflatoxin because this these fungi competitively exclude the fungi that produce aflatoxin.

Another possibility shifts crop production further north or further south geographically where the climate is cooler or wetter to reduce aflatoxin risk. That, however, impacts farms that have been passed down for generations.

For consumers concerned about eating field corn and their aflatoxin risk, Wu suggests eating your greens and garlic. “Green leafy vegetables are good for your overall health,” Wu said. “Chlorophyll has a sandwich molecular structure that traps aflatoxin molecules so that humans excrete them before the toxin can enter our bloodstream.”

Also, cruciferous vegetables like broccoli, cauliflower, kale and allium vegetables like garlic, onions and leeks can help detoxify carcinogens in our bodies.

“We predict seeing an increase in aflatoxin problems over the next 10-20 years,” Wu said. “So, we need to rely on technologies and a whole suite of interventions that can reduce the problem.”


Story Source:

Materials provided by Michigan State University. Original written by Emilie Lorditch. Note: Content may be edited for style and length.

Spain – Multinational monophasic Salmonella typhimurium outbreak caused by chocolate products

ACSA

This year the Report of the European Center for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) on this outbreak related to Kinder chocolate products, produced by the Ferrero group, has been published. Given the wide distribution and durability of these products, and the increase in mobility due to the Easter holidays, the outbreak, of 212 cases, affects 5 European countries: France (59 cases), Belgium (54 cases), Germany (18 cases) , the United Kingdom (80 cases) and the Spanish State (1 case). There is even a case in the US.

The first patient was confirmed in the United Kingdom, on January 7, 2022, with a sampling date of December 21, 2021. On February 17, 2022, the United Kingdom, which had already carried out Whole Genome Sequencing (WGS), notified the ECDC of 18 cases of Salmonella typhimurium monophasic BURST Group 1 (eBG1).

Since the elaboration of the ECDC Report, new cases have been detected which are already taken into account in this writing. The ECDC and EFSA are working on an update of the outbreak assessment that is to be published in mid-May.

The most affected population have been children under 10 years of age and women. Many of the affected people have had to be hospitalized since they presented very serious symptoms.

The outbreak strain is resistant to six families of antibiotics: penicillin, aminoglycosides (streptomycin, kanamycin, gentamicin), phenicols, sulfonamides, trimethoprim, and tetracycline. Resistance to aminoglycosides, phenicols, and trimethoprim is rare in monophasic Salmonella typhimurium and can be used for detection of probable cases. It is susceptible to fluoroquinolones, azithromycin, and third-generation cephalosporins.

The chocolate was produced in Belgium and distributed in at least 113 countries. On April 10, 2022, the International Network of Food Safety Authorities (INFOSAN) launched a global alert. Salmonella Typhimurium identified single-phase in the buttermilk tanks of the Ferrero plant in Arlon, in December 2021 and in January 2022. After implementing hygiene measures and obtaining negative tests for salmonella, the Kinder products involved were distributed throughout Europe and throughout the world. However, on April 8, 2022, the Belgian food safety authority reported through RASFF that the investigation at the plant revealed that the management of the contamination carried out by the company did not ensure the healthiness of the products they produced. , for which he ceased its production. It also extended the recall of all batches manufactured at this facility, regardless of batch number and expiration date. The Luxembourg Public Prosecutor’s Office has opened an investigation.It should be noted that Ferrero has production plants in more countries (France, Germany, Poland, etc.), where microbiological tests are also being carried out, given that they share some suppliers. For example, the results obtained in the plant located in Germany are, at this point, all negative, and the cases detected are linked to products made in Belgium. The withdrawal of Ferrero products has been carried out in many countries, including in some where, for the moment, no cases have been declared, such as Canada. and the detected cases are linked to products made in Belgium. The withdrawal of Ferrero products has been carried out in many countries, including in some where, for the moment, no cases have been declared, such as Canada and the detected cases are linked to products made in Belgium. The withdrawal of Ferrero products has been carried out in many countries, including in some where, for the moment, no cases have been declared, such as Canada.

In the Spanish State, on April 6, products with expiration dates between May and August of this year were withdrawn from the market, as a precautionary measure.

Salmonella-contaminated foods are usually not altered in appearance, smell, or taste. 

USA – In Food Safety Study, 25% of Participants Contaminated Salad with Raw Chicken

NCSU

Foodborne Pathogen

In a study aimed at assessing the impact of washing poultry on kitchen contamination, researchers found that more than a quarter of study participants contaminated salad with raw poultry – including many study participants who did not wash the poultry. The study highlights the importance of hand-washing and cleaning and sanitizing the kitchen in order to reduce the risk of foodborne illness when cooking at home.

Washing raw poultry is not recommended, due to concerns about inadvertently contaminating other foods and surfaces – and increasing the risk of foodborne illness.

“We wanted to know what effect an educational intervention would have on getting people to stop washing poultry before cooking, and what effect any resulting change in behavior might have on reducing contamination in the kitchen,” says Ellen Shumaker, corresponding author of the study and an extension associate at North Carolina State University. “We also wanted to get a better idea of how, if at all, washing poultry actually led to increased contamination in the kitchen.”

For the study, researchers recruited 300 home cooks who said they washed poultry before cooking it. The researchers sent food safety information to 142 of the study participants via email, outlining risk-reduction efforts – including the recommendation to not wash raw poultry during food preparation. The remaining 158 study participants did not receive the education intervention.

All 300 study participants were then invited to test kitchens equipped with video cameras that filmed meal preparation. Participants were asked to cook chicken thighs and prepare a salad. After preparing the chicken thighs, but before putting the chicken in the oven, participants were called out of the kitchen to conduct a short interview. Participants were then sent back into the kitchen to cook the chicken thighs, prepare the salad, and clean the kitchen as they would at home.

What the study participants didn’t know was that the chicken thighs were inoculated with a harmless strain of bacteria, which the researchers would be able to detect. This allowed researchers to swab surfaces in the kitchen to see whether any cross-contamination occurred during the food preparation and cooking process.

When study participants left the kitchen to conduct the interview, researchers swabbed the kitchen to identify any potential contamination. This process was repeated after each participant had completed cooking the meal and cleaned the kitchen. The prepared salad was also tested for possible contamination.

Ninety-three percent of the participants who received the intervention did not wash the chicken, as compared to 39% of the participants who did not receive the intervention.

However, the researchers were surprised to see that people who did wash the chicken and people who didn’t wash the chicken had similar levels of contamination from the raw chicken in their prepared salads.

Research – Do You Really Need to Wash Fruits and Vegetables?

AARP

During the journey from farm to table, the fruits, vegetables and other foods we eat are exposed to countless people, places, substances and surfaces before ever reaching our mouths. It would seem a given, then, that everything we bring home from the grocery store needs to be thoroughly washed and sanitized.

“Produce comes from the environment; it comes from the ground. The way that it’s grown and harvested, it can have dirt on it and other bacteria,” says Meredith Carothers, technical information specialist at the U.S. Department of Agriculture (USDA). “Unlike meat and poultry, which is packaged, a lot of times produce is just out in the grocery store on display.”

From a food safety standpoint, experts say it’s not necessary to wash all foods. In fact, washing some foods can actually increase the risk of contamination and illness. To help clear up any confusion, we asked Carothers to break down the do’s and don’ts of food washing.

Rules for washing produce

Do rinse fruits and vegetables under running water. After produce is harvested, it gets sorted, delivered and put on display in the grocery store. During this process there are many opportunities for produce to encounter a number of hands and surfaces. Before consuming fresh produce, remove any torn or bruised parts (bacteria that can cause illness thrive in these places) and rinse under running water to remove germs and dirt.

Do scrub hard produce with a clean brush. Foods like potatoes or apples can be scrubbed to thoroughly remove dirt from the exterior, including crevices that rinsing alone may not reach.

Do dry rinsed produce on a clean surface. That means spreading a clean cloth or paper towel on a clean surface to avoid recontamination. If you use a salad spinner, make sure it’s clean before you add greens to it, and clean it again between batches.

Don’t wash produce labeled “prewashed” or “ready to eat.” It is already safe to eat out of the package. Just make sure that prewashed produce doesn’t encounter unclean surfaces or utensils — especially if those surfaces have had raw meat or its juices on them.

Don’t use soap to clean produce. The USDA does not recommend any type of detergent on fruits or vegetables because it can leave behind a film that is not intended to be consumed. Some produce is also porous and may absorb the soap. Although you can buy commercial produce washes, they aren’t approved or labeled by the Food and Drug Administration (FDA) and are not recommended.

Don’t soak produce. Soaking may remove the germs initially, but the now-tainted water can recontaminate your produce as well as nearby surfaces. When produce is rinsed under running water, the dirt and germs go down the drain.

Research – Pathogens can hitch a ride on plastic to reach the sea

Phys Org

Microplastics are a pathway for pathogens on land to reach the ocean, with likely consequences for human and wildlife health, according to a study from the University of California, Davis.

The study, published April 26 in the journal Scientific Reports, is the first to connect microplastics in the ocean with land-based pathogens. It found that microplastics can make it easier for disease-causing pathogens to concentrate in plastic-contaminated areas of the ocean.

The pathogens studied—Toxoplasma gondii, Cryptosporidium (Crypto) and Giardia—can infect both humans and animals. They are recognized by the World Health Organization as underestimated causes of illness from shellfish consumption and are found throughout the ocean.

“It’s easy for people to dismiss plastic problems as something that doesn’t matter for them, like, ‘I’m not a turtle in the ocean; I won’t choke on this thing,'” said corresponding author Karen Shapiro, an infectious disease expert and associate professor in the UC Davis School of Veterinary Medicine. “But once you start talking about disease and health, there’s more power to implement change. Microplastics can actually move germs around, and these germs end up in our water and our food.”

Research – Cryptosporidium: Still Open Scenarios

MDPI

water contamination

Cryptosporidiosis is increasingly identified as a leading cause of childhood diarrhea and malnutrition in both low-income and high-income countries. The strong impact on public health in epidemic scenarios makes it increasingly essential to identify the sources of infection and understand the transmission routes in order to apply the right prevention or treatment protocols. The objective of this literature review was to present an overview of the current state of human cryptosporidiosis, reviewing risk factors, discussing advances in the drug treatment and epidemiology, and emphasizing the need to identify a government system for reporting diagnosed cases, hitherto undervalued.