Category Archives: Research

Hong Kong – Centre for Food Safety announces test results on Lunar New Year food (first phase)

CFS

The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department today (January 15) announced the test results of a recently completed seasonal food surveillance project on Lunar New Year (LNY) food (first phase). The test results of around 570 samples collected were satisfactory, except for a date sample found to contain a preservative at a level exceeding the legal limit and in breach of the food labelling regulation and a rice cake sample found with sodium content inconsistent with the declared content on its nutrition label, which were announced earlier.

A spokesman for the CFS said, “The LNY is coming soon and the CFS is conducting this seasonal food surveillance project in two phases. During the first phase of the project, different types of LNY food including steamed puddings (e.g. turnip puddings and festive cakes), fried dumplings (e.g. sesame balls and crispy triangles), candies, glutinous rice balls, melon seeds and dried aquatic products were collected from different retailers (including online retailers) for chemical and microbiological tests as well as nutrition content analysis.”

Chemical tests targeted preservatives, colouring matters, metallic contaminants and others. Microbiological tests covered different food poisoning pathogens. For nutrition content analysis, the contents of total fat, sodium and sugars of the samples were tested to see if the test results were consistent with the declared values on the nutrition labels.

The spokesman urged the food trade to observe the relevant laws and regulations in the preparation of food, follow Good Manufacturing Practice and use permitted food additives only in an appropriate manner. Retailers should source food from reliable suppliers, and conduct quality checks of incoming materials and end products to ensure that ingredients used are within legal standards. In addition, the food trade should maintain proper records in accordance with the requirements of the Food Safety Ordinance to allow source tracing if needed.

The spokesman also advised consumers to buy LNY food from reliable retailers with good hygiene conditions; make sure the packaging of prepackaged cakes and snacks is intact and the products have not expired; refer to the nutrition labels on the sugar, salt (sodium) and fat content and more for healthy choices; and pay attention to the hygiene conditions of food containers and the personal hygiene of staff when buying loose-packed food (e.g. candied lotus seeds, nuts and melon seeds).

“Consumers should choose food products with natural colours. Bright white pistachios may have been bleached and melon seeds with an unnatural gloss may have had mineral oil added. Consumption of these food products can cause gastrointestinal discomfort,” the spokesman said.

“Festive cakes that are not for immediate consumption should be kept refrigerated or stored according to the instructions on the package, and should be eaten before they expire. Reheat hot-served festive cakes thoroughly before consumption, consume them as soon as possible, and avoid keeping them at room temperature for a long time. Foods like nuts and melon seeds should not be kept for a long time. Those with mould or an abnormal smell or taste should not be eaten,” he added.

The spokesman reminded the public to maintain a balanced diet and avoid foods that are high in energy, sugar, salt or fat during the LNY.

The CFS will continue to conduct surveillance on LNY food and the second-phase results will be released in a timely manner to ensure food safety.

Research – Breakthrough in understanding ‘tummy bug’ bacteria

Science Daily

Scientists have discovered how bacteria commonly responsible for seafood-related stomach upsets can go dormant and then “wake up.”

Vibrio parahaemolyticus is a marine bacterium that can cause gastroenteritis in humans when eaten in raw or undercooked shellfish such as oysters and mussels.

Some of these bacteria are able to turn dormant in poor growth conditions such as cold temperatures — and can remain in that state of hibernation for long periods before resuscitating.

University of Exeter scientists have identified a population of these dormant cells that are better at waking up, and have discovered an enzyme involved in that waking up process.

“Most of these bacteria die when they encounter poor growth conditions, but we identified sub-populations of bacteria that are able to stay dormant for long periods of time,” said lead author Dr Sariqa Wagley, of the University of Exeter.

“We found that this population has a better ability to revive when conditions improve.

“Our tests show that when these dormant bacteria are revived they are just as virulent and able to cause disease.”

The findings could have implications for seafood safety, as dormant cells are not detectable using routine microbiological screening tests and the true bacterial load (amount of bacteria) could be underestimated.

“When they go dormant, these bacteria change shape, reduce respiration activities and they don’t grow like healthy bacteria on agar plates used in standard laboratory tests, so they are much harder to detect,” Dr Wagley explained.

“Using a range of tools, we were able to find dormant bacteria in seafood samples and laboratory cultures and look at their genetic content to look for clues in how they might survive for long periods.

“It is important to note that thorough cooking kills bacteria in seafood.

“Our results may also help us predict the conditions that dormant bacteria need in order to revive.”

Working with the seafood industry, the Exeter team identified a lactate dehydrogenase enzyme that breaks down lactic acid into pyruvate, a key component of several metabolic pathways (chemical reactions in a cell).

The findings suggest that lactate dehydrogenase is essential both for maintaining bacterial dormancy and resuscitation back to an active form.

Vibrio parahaemolyticus usually grows in warm and tropical marine environments, although Dr Wagley said that due to rising sea temperatures in recent years it is now prevalent in UK waters during the summer months.

During the winter, it is not detected in the marine environment around the UK and it is thought to die due to the cold winter temperatures.

This study could explain how Vibrio parahaemolyticus is able remerge in the environment during the summer.

The study was partly funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional funding and support from Lyons Seafoods.

Research – Condensation removal practices and its potential for contributing to environmental pathogen contamination in food processing facilities

Journal of Food Protection

listeria

Food manufacturers often use squeegees as a tool to remove condensation from overhead surfaces. This practice is done to reduce the likelihood of environmental pathogen contamination by eliminating condensed water droplets that could fall from overhead surfaces during production. However, this practice may actually spread environmental pathogens across these surfaces, defeating its purpose and further increasing the risk for contamination in the processing area. To understand the risk associated with this common practice, test pipes inoculated with Listeria innocua ATCC 33090 were exposed to steam to produce condensation, which was then removed by squeegees. The pipe surfaces, droplets, and squeegees were subsequently analysed for Listeria to determine the distance the organism spread across the pipe, and how many organisms were transferred to the droplets and the squeegees. Results showed that Listeria travelled as far as 16 inches across the surface of the pipe, and bacterial transfer to the droplets decreased as the squeegee travelled further away from the contaminated area. Sanitisers alone were able to remove about 1 – 2 log CFU/in 2 of Listeria from the squeegee blades. Among the cleaning protocol evaluated, an extensive cleaning regimen was able to remove 3 – 4 log CFU/in 2 , which would be recommended to reduce the risk associated with environmental pathogens transfer. This study provides evidence that supports recommendations for minimising the cross-contamination risk associated with condensation management practices.

Switzerland – Early detection for food safety

FFSVO

For sustainable assurance of food safety and the prevention of fraud, the FSVO identifies newly emerging risks to the health of Switzerland’s population. Early detection of this kind allows appropriate action to be taken in real time.

The FSVO compiles the most important food safety information every month 

Monitoring developments in the field of food safety is an essential task of early detection. This is why the FSVO summarises and evaluates the main information in Seismo Info. The publication is sent out by newsletter.

The aim of early detection for food safety is to identify and assess potential risks of food to the health of consumers.

The FSVO distinguishes between different types of risk:

  • Microbiological risks in foodstuffs and food fraud and deception
  • Chemical risks in foodstuffs and commodities
  • Nutrition-related risks

Monitoring system

The detection of newly emerging risks requires vigilant monitoring of societal and ecological changes, technological developments, economic trends and political conditions.

To perform these tasks, the FSVO manages an early detection system for food safety. This system considers information from a variety of sources, as well as the opinion of experts from the federal government, the cantons, industry and universities. The FSVO is also part of an international network that regularly shares information on new risks, assesses these risks and discusses the action to be taken.

Information and communication

The information gathered is compiled in the ADURA database, which can be accessed by federal and cantonal experts and to some extent also by the public.

The FSVO summarises and evaluates the main information every month in Seismo Info. The publication is communicated via the «Food safety and nutrition» newsletter (Subscription in French, German or Italian).

«Briefing letters» are short summaries of issues. They are characterised by in-depth research on a specific topic. Their purpose is to draw attention to hazards or risks that could endanger food safety in the medium to long term.

Anyone can contribute to early detection by submitting information to seismo@blv.admin.ch. Specialists check the information and incorporate it into the ADURA database or Seismo Info as appropriate.

Research – Handwashing Observations in Fast-Food and Full-Service Restaurants: Results from the 2014 FDA Retail Food Risk Factors Study

Journal of Food Protection

Properly executed handwashing by food employees can greatly minimize the risk of transmitting foodborne pathogens to food and food contact surfaces in restaurants. However, food employee handwashing is often not done correctly nor does it occur as often as it should. The purpose of this study was to assess the relative impact of 1) the convenience and accessibility of handwashing facilities; 2) the maintenance of handwashing supplies, 3) multi-unit status, 4) having a Certified Food Protection Manager, and 5) having a Food Safety Management System on compliance with proper handwashing. Results showed marked differences in handwashing behaviors between fast-food and full-service restaurants. Forty-five percent of fast-food restaurants and 57% of full-service restaurants were found to be out of compliance for washing hands correctly. Fifty-seven percent of fast-food establishments and 78% of full-service establishments were out-of-compliance for employee hands being washed when required. Logistic regression results point toward the benefits of accessibility and maintenance of the handwashing sink and food establishments having a Food Safety Management System to increase the likelihood of employees washing hands when they are supposed to and washing them correctly when they do.

Research – Bacillus cereus food poisoning with fatal multi-organ failure.

BMJ

bacillus

This case represents a rare fulminant course of fried-rice associated food poisoning in an immunocompetent person due to pre-formed exotoxin produced by Bacillus cereus, with severe manifestations of sepsis, including multi-organ (hepatic, renal, cardiac, respiratory and neurological) failure, shock, metabolic acidosis, rhabdomyolysis and coagulopathy. Despite maximal supportive measures (continuous renal replacement therapy, plasmapheresis, N-acetylcysteine infusion and blood products, and broad-spectrum antimicrobials) and input from a multidisciplinary team (consisting of infectious diseases, intensive care, gastroenterology, surgery, toxicology, immunology and haematology), mortality resulted. This case is the first to use whole genome sequencing techniques to confirm the toxigenic potential of B. cereus. It has important implications for food preparation and storage, particularly given its occurrence in home isolation during the COVID-19 pandemic.

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Research – Research examines Listeria tolerance to sanitizers

CPS

With little data on whether Listeria monocytogenes develops tolerance to commonly used sanitizers, debates continue on whether or how frequently processing facilities should rotate sanitizing agents.
Xiangyu Deng, Ph.D., with the University of Georgia, said he hoped his research project will fill in knowledge gaps to help the industry make more informed decisions about the need for chemical rotation. Ultimately, the results may lead to development of a genetics-based tool to assess the risk of Lm developing sanitizer tolerance.
Currently, the Food and Drug Administration and the U.S. Department of Agriculture Food Safety and Inspection Service recommend rotating sanitizers in fresh-cut processing facilities to minimize the chances of pathogens – and particularly Lm – developing tolerance.
Key Take-Aways
• Researchers seek to fill in gaps about potential for Listeria monocytogenes to develop tolerance to commercial sanitizers.
• The research will evaluate how different sanitizer levels and lengths of exposure affect the degree of tolerance in selected Listeria strains.
• Researchers are collaborating with two produce processors to relate their lab results to real-world scenarios.
• Ultimately they hope their results lead to a genetics-based tool to assess the risk of Listeria developing sanitizer tolerance.
“I think those recommendations, because there’s not much data on the specifics of sanitizer tolerance in Listeria, are made out of an abundance of caution,” Deng said. But he has not heard of any confirmed case where the pathogen developed tolerance to commonly used sanitizers in produce processing facilities.
Even if the pathogen does develop tolerance through sublethal exposure to sanitizers, little data exists to predict how long tolerance will last before reverting to susceptibility, he said.
Joining Deng as co-principal investigator is Henk C. den Bakker, Ph.D., and also with the University of Georgia.
The project, titled “Possibility, duration and molecular predictors of sanitizer tolerance in Listeria monocytogenes,” is examining the potential for resistance to chlorine and quaternary ammonium compounds (quats).
Acquired resistance occurs when an organism is exposed to sublethal doses of a control agent. Those that survive phenotypically display, but don’t genetically acquire, elevated tolerance to the agent.
Conversely, if products are rotated and the tolerant organisms are no longer exposed to the original chemical, the population is unlikely to maintain the tolerance indefinitely. How long it takes for this return to susceptibility is one question Deng hopes to shed more light on.
As part of the project, the researchers screened over 33,000 publicly available Lm genomes for resistance to quats. The researchers found 21% of the isolates harbored quat-resistance genes.
But Deng said the high percentage is not necessarily cause for concern.
“It doesn’t necessarily mean reduced efficacy because the concentration of commercial sanitizer should be enough to kill even the ones with resistance genes,” he said.
Using a set of 359 isolates obtained from the FDA and Purdue University that covered a wide spectrum of sanitizer tolerance, the researchers also developed a high-throughput method to measure the minimum amount of chemical needed to inhibit the organism. Of those isolates, 126 originated from 22 produce commodities, 232 were from packinghouses and retailers, and one was a clinical sample.
The isolate collection and this method will be used to identify genetic markers that can predict sanitizer tolerance.
As part of the project’s second year, the researchers plan to evaluate how different sanitizer levels and lengths of exposure affect the degree and duration of acquired tolerance in selected Lm strains. They also plan to characterize the transcriptomic shifts that accompany the reversion to sensitivity.
In addition, Deng is collaborating with two produce processing companies – one in Texas and another with multiple locations in the United States. Although he would have liked to have visited at least some of the facilities during the fall season, his travel plans were delayed because of the ongoing COVID-19 pandemic.
But Deng still plans to visit the processors to collect samples to determine residual sanitizer concentrations between sanitizing shifts.
“I think it’s very important if we want to relate our findings to real-world situations,” he said. “We’ve used concentrations in the lab that will induce resistance, but are these concentrations relative to the real world?”

Research – Botulism breakthrough? Taming botulinum toxin to deliver therapeutics

Boston Childrens Hospital

kswfoodworld

CDC Image

While rare, botulism can cause paralysis and is potentially fatal. It is caused by nerve-damaging toxins produced by Clostridium botulinum — the most potent toxins known. These toxins often lurk in contaminated food (home canning being a major culprit). Infants can also develop botulism from ingesting C. botulinum spores in honey, soil, or dust; the bacterium then colonizes their intestines and produces the toxin.

Once paralysis develops, there is no way to reverse it, other than waiting for the toxins to wear off. People with serious cases may need to go on ventilators for weeks or months. But a new botulism treatment and delivery vehicle, described today in Science Translational Medicine, could change that.

“Currently, there are anti-toxins, but these only work before the toxins enter the motor neurons,” says Min Dong, PhD, a researcher in the Boston Children’s Hospital Department of Urology and corresponding author on the paper. “What we have developed is the first therapy that can eliminate toxins after they get inside neurons.”

If proven in humans, the approach would represent a breakthrough in treating botulism. In mice, the treatment successfully got inside neurons and reversed muscle paralysis within hours. It also enabled mice to withstand doses of botulinum toxin that would otherwise be lethal.

Research – Genetic insights could help tackle food bug

Roslin

Scientists have identified regions in the genetic makeup of chickens that are linked to resistance to Campylobacter  ̶  the leading bacterial cause of food-borne gastroenteritis worldwide.

Data obtained in the study inform the extent to which parts of the chicken genetic code can be linked to the prevalence of Campylobacter in the chicken gut.

A study led by researchers from the Roslin Institute, in collaboration with the poultry breeding company Aviagen, investigated the genetic make-up of 3,000 chickens bred for meat, to discover whether parts of their genetic code were associated with resistance to Campylobacter colonisation.

This was achieved by looking for variation at specific positions in the chickens’ genome and their association with numbers of Campylobacter in the gut of the birds.

Scientists combined this with analyses of the expression of genes in chickens that were resistant or susceptible to colonisation by the bacteria.

All the chickens were naturally exposed to Campylobacter present in their environment, which mimics how chickens are exposed on a commercial farm.

Campylobacter infections are common in people, who can develop diarrhoea and severe complications after handling or eating contaminated chicken meat.

Each year, it is estimated that more than 500,000 people in the UK are infected, costing the country approximately £50 million.

These results show that whilst there are genetic factors that influence Campylobacter colonisation, these factors play a minor role and therefore it is crucial to characterise and understand the role of the non-genetic and environmental factors to further reduce Campylobacter levels in poultry.

Research – Evaluation of sodium hypochlorite and peroxyacetic acid to prevent transfer of surface‐attached Listeria monocytogenes to produce

Wiley Online

kswfoodworld

Sporadic contamination of produce with Listeria monocytogenes (Lm) is a recurrent problem. Ways for contamination to occur include transfer of the pathogen to produce from processing surfaces or soil particles to which it has become attached. Since it is known that surface‐attached Lm is less susceptible to antimicrobials than Lm grown in liquid culture, the goal of the current study was to determine if Lm grown on surfaces and released into water retained its higher tolerance of antimicrobials. In addition, transfer of Lm from surfaces or soil particles to blueberries, mung beans and spinach leaves in the presence of the antimicrobials, sodium hypochlorite (NaOCl) adjusted to pH 6.8 and peroxyacetic acid (PAA), was studied. The experiments were carried out with a cocktail of six Lm strains and strains obtained from produce processing plants. Results indicated that Lm released from surfaces was as susceptible to the two antimicrobials as Lm grown in liquid culture and was inactivated within seconds by an initial concentration of 100 ppm of NaOCl or PAA. Transfer of Lm grown on stainless steel coupons to blueberries in wash water was not observed at NaOCl concentrations as low as 20 ppm. In contrast, transfer of Lm from washed soil particles (COD = 1.7 ± 0.89 mg/l) in contact with mung beans was observed even at initial NaOCl or PAA concentrations of 250 ppm. Lm released from washed soil particles to which it was attached to spinach leaves could be detected in the presences of 20 ppm of NaOCl and PAA and occasionally even in the presence of 100 and 250 ppm of the antimicrobials.