Category Archives: Research

Research – Root Cause Analyses Are ‘Critical to Preventing Foodborne Illnesses’

PEW Trusts

When foodborne illnesses are linked to products regulated by the Food and Drug Administration, the agency’s top priority is limiting harm to consumers with swift removal of unsafe items from the market. But FDA’s work doesn’t end there. The agency increasingly uses an investigative approach called root cause analysis (RCA) to identify how and why dangerous bacteria or other pathogens contaminated specific products and what steps could help businesses prevent a recurrence of these problems. The FDA publicly shares findings and recommended corrective actions from each RCA so that food growers and manufacturers across an industry can apply them to their food safety systems.

Frank Yiannas, deputy commissioner for food policy and response, heads FDA’s efforts to reduce food contamination risks and respond to foodborne outbreaks. He spoke with The Pew Charitable Trusts about the importance of RCA in this work and cited a new Pew report that offers guidance for effective analyses to food companies and government agencies. His responses have been edited for clarity and length.

Germany – Survey finds low Campylobacter knowledge in Germany

Food Safety News 

Consumer knowledge in Germany of Toxoplasma was better than that of Campylobacter, according to a recent report on a study.

Researchers surveyed 1,008 consumers in August 2017 in Germany via an online panel on Campylobacter, Salmonella and Toxoplasma and transmissibility via meat. The questionnaire had 43 questions in five sections.

Consumers were most informed about Salmonella and general knowledge of Toxoplasma is better than Campylobacter. Campylobacter, despite its high incidence in Germany, was largely unknown to consumers.

With almost 70,000 confirmed cases in 2017, Campylobacter is the main bacterial infection causing diarrhoeal disease reportable in Germany. Second was salmonellosis with 14,269 confirmed infections. Only seven cases of congenital human toxoplasmosis were confirmed in 2017.

A previous survey by the German Federal Institute for Risk Assessment (BfR) found only 28 percent of people had heard of Campylobacter.

Research – Scale‐up model of forced air‐integrated gaseous chlorine dioxide for the decontamination of lowbush blueberries

Wiley Online 

Gaseous chlorine dioxide (ClO2) is a promising sanitizer for frozen products because of its efficacy under nonthermal and waterless conditions. A major knowledge gap exists between laboratory trials and effectiveness at the industrial scale. To address this, a pilot study implementing a pallet‐sized fumigation container (60 harvest totes) was designed for gaseous ClO2. Fifty kilograms of blueberries were exposed to initial dose of 57.46 mg/L, representing a treatment of 2.35 mg/g of blueberries. Blueberries remained enclosed for 10 hr. Reduction of all viable cells, coliforms, yeasts, and molds were measured by plating treated samples on Tryptic Soy Agar, Violet Red Bile Agar, and Dichloran Rose Bengal Chloramphenicol Agar and compared to untreated controls. The results demonstrate that a significant reduction of 1.5 log CFU/g can be achieved against coliforms after ClO2 exposure. Our findings demonstrate a cost‐effective procedure that could be adapted to commercial processing.

Research – Study shows how diligent we have to be to keep surfaces germ-free

Science Daily

During the COVID-19 pandemic, every frequently touched surface outside our home seems as dangerous as a hot pot right out of the oven. We won’t get burned if we touch it, but we might get infected with a potentially dangerous virus.

A recent study suggests that even organized efforts to clean surfaces can fall short, a reminder for us all that keeping our surroundings clean may require some additional work.

For 5 ½ weeks, researchers tagged surfaces of a small-animal veterinary practice daily with a fluorescent dye visible only under black light. They checked tagged surfaces 24 hours later to see if the marks were showing. Surfaces were considered cleaned if the dye was completely removed.

Results showed that overall, only half of all surfaces were adequately cleaned during the study period. Human-touch surfaces — such as medical instruments, dog run handles, and computer mice and keyboards — were cleaned less frequently than areas touched primarily by animals. The results were similar to studies from other veterinary clinics.

Research – Modeling the inactivation of Bacillus cereus by infrared radiation in paprika powder (Capsicum annuum)

Wiley Online 

Infrared (IR) irradiation, a novel technology for modeling of decontamination of Bacillus cereus in paprika powder was evaluated and the effect on temperature profiles and total phenolic content was determined. The highest reduction in B. cereus count (2.3 log CFU/g) was achieved after a holding time of 1 min at 200 W IR power and 5 cm distance. The rapid rise in temperature was observed in surface paprika powder and the highest temperature at 200 W IR power and 5 cm distance reaching to 127.8°C. An increase in IR power and a decrease in sample distance of the IR lamp caused a significant decrease in the total phenolic content. The Double Weibull model closely predicted the inactivation of B. cereus in paprika powder by IR irradiation.

Research – Don’t freak out: These are the microbes living on your tongue

Science Mag

STEVEN WILBERT AND GARY BORISY/FORSYTH INSTITUTE

Microbes are everywhere in our guts—and in our mouths. Now, a new study reveals our tongue-dwelling companions aren’t all mixed together randomly; instead, they seem to prefer living close to their own kind, separating out into distinct groups based on their species.

Researchers started by scraping the tongues of 21 healthy human volunteers. Then, they used fluorescent tags to identify specific groups of bacteria, some of which produce nutrients for us, so they could see exactly where each one lived on the tongue’s surface. Without exception, the bacteria formed tight-knit, well-defined clusters of the same species, the researchers report today in Cell Reports.

The clusters (above) resemble a microbial rainbow under the microscope. For instance, Actinomyces bacteria, in red, grow close to the epithelial tissue of the tongue, shown in gray, while Rothia bacteria, in cyan, form long patches between other communities. Streptococcus, in green, form a thin crust on the edge of the tongue and slender veins in the interior. By looking at the images, the researchers could guess at how these colonies establish themselves and grow over time.

Research – Human foodborne listeriosis in England and Wales, 1981 to 2015

Cambridge Press

Almost all cases of human listeriosis are foodborne, however the proportion where specific exposures are identified is small. Between 1981 and 2015, 5252 human listeriosis cases were reported in England and Wales. The purpose of this study was to summarise data where consumption of specific foods was identified with transmission and these comprised 11 sporadic cases and 17 outbreaks. There was a single outbreak in the community of 378 cases (7% of the total) which was associated with pâté consumption and 112 cases (2% of the total) attributed to specific foods in all the other incidents. The proportion of food-attributed cases increased during this study with improvements in typing methods for Listeria monocytogenes. Ten incidents (one sporadic case and nine outbreaks of 2–9 cases over 4 days to 32 months) occurred in hospitals: all were associated with the consumption of pre-prepared sandwiches. The 18 community incidents comprised eight outbreaks (seven of between 3 and 17 cases) and 10 sporadic cases: food of animal origin was implicated in 16 of the incidents (sliced or potted meats, pork pies, pâté, liver, chicken, crab-meat, butter and soft cheese) and food of non-animal origin in the remaining two (olives and vegetable rennet).

USA – New Oyster Rules Aim to Reduce Vibrio Cases

Coastal Review

Division of Marine Fisheries Director Steve Murphey implemented the new oyster harvest control measures through Proclamation SS-1-2020  and Proclamation SS-2-2020, both issued Monday.

The Division of Marine Fisheries announced that while the state’s public health record concerning shellfish-related illnesses is one of the best in the country, the number of Vibrio cases nationwide had increased in recent years. Vibrio are naturally occurring bacteria in coastal waters that can cause illness in humans if precautions are not taken during the warmer months of the year.

The new regulations also will bring the state into conformity with guidance from the National Shellfish Sanitation Program, which is the federal, state and industry cooperative program recognized by the U. S. Food and Drug Administration and the Interstate Shellfish Sanitation Conference for the sanitary control of shellfish produced and sold for human consumption.

The changes include the following new requirements to:

  • Shade oysters harvested between May 1 and Oct. 14. This involves providing shade over harvested oysters or covering the oysters with a light-colored tarp or other nontoxic material while they are stored on the vessel, floating container when the oysters are not submerged, or a vehicle (this is already required for the harvest of clams in the summer).
  • Resubmerge oysters exposed to the air for greater than five hours between May 1 and Oct. 14 (this might occur during air-drying or de-fouling with gear such as OysterGro). The oysters must remain submerged for at least 14-days to abate Vibrio levels that may have been elevated.
  • Clarify that when working in intertidal waters the term “start of harvest” begins when the oyster is first exposed by the receding tide.
  • Clarify the tagging procedures when oysters leave the lease for tumbling or culling.
  • Resubmerge oysters moved from one growing area to another for at least 21 days prior to harvest (Certified shellfish dealers with a wet storage permit are exempt). This may prevent the closure of multiple growing areas in the event of an illness outbreak.

Previously implemented regulations pertaining to recording the start of harvest on the harvest tag and delivering the oysters to a licensed dealer within a specified time remain in effect.

For more information, contact Shannon Jenkins, chief of the division’s Shellfish Sanitatio

Research – Outbreak of Clostridium perfringens food poisoning linked to leeks in cheese sauce: an unusual source

Cambridge Uni Press

Between 11–13 December 2018, local public health authorities in the West Midlands, England were alerted to 34 reports of diarrhoea with abdominal cramps. Symptom onset was ~10 h after diners ate Christmas meals at a restaurant between 7–9 December 2018. A retrospective case-control study, environmental and microbiological investigations were undertaken to determine the source and control the outbreak. An analytical study was undertaken with odds ratios (OR) and 95% confidence intervals (CI). Forty persons were recruited to the analytical study (28/40 cases). Multivariable analysis found that leeks in cheese sauce was the only item associated with illness (aOR 51.1; 95% CI 4.13–2492.1). Environmental investigations identified significant lapses in food safety, including lapses in temperature control during cooking and hot holding, likely cross-contamination between raw and cooked foods and the reuse of leftover cheese sauce for the next day’s service. No food samples were taken during the exposure period. Two faecal samples were positive for Clostridium perfringens with one confirming the enterotoxigenic gene. Cheese sauce is an unusual vehicle for the organism and the first time this has been reported in England.

Research – Bacteria form biofilms like settlers form cities

Science Daily biofilm

Biofilms are composed of bacteria living in a densely packed and organized community. Research paired high-level imaging tools with an algorithm to track a biofilm as it formed. Biofilm growth at multiple scales, they found, mimics aspects of how cities emerge from individual settlers.

The findings show that, as individual bacteria multiply and grow into a dense and sticky biofilm, such as the community that forms dental plaque, their growth patterns and dynamics mirror those seen in the growth of cities.

“We take this ‘satellite-level’ view, following hundreds of bacteria distributed on a surface from their initial colonization to biofilm formation,” says Hyun (Michel) Koo, a professor in Penn’s School of Dental Medicine and senior author on the work. “And what we see is that, remarkably, the spatial and structural features of their growth are analogous to what we see in urbanization.”

This new perspective on how biofilms grow could help inform efforts to either promote the growth of beneficial microbes or break up and kill undesirable biofilms with therapeutics.