Category Archives: Food Microbiology Research

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

Posted on January 21, 2021 by | Leave a comment

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.

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Posted in food handler, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Hand Washing, microbial contamination, Microbiology, Research, Uncategorized

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

Posted on January 20, 2021 by | Leave a comment

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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Posted in Bacillus, Bacillus cereus, Exotoxin, food contamination, Food Hazard, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Poisoning, Food Safety, Food Testing, Food Toxin, Research, sepsis

Research – Research examines Listeria tolerance to sanitizers

Posted on January 20, 2021 by | Leave a comment

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?”

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Research – Botulism breakthrough? Taming botulinum toxin to deliver therapeutics

Posted on January 20, 2021 by | Leave a comment

Boston Childrens Hospital

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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.

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Posted in Bacterial Toxin, botulism, Clostridium botulinum, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Toxin, microbial contamination, Microbiology, Research, Toxin

Research – Genetic insights could help tackle food bug

Posted on January 19, 2021 by | Leave a comment

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.

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Posted in Campylobacter, food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Testing, microbial contamination, Microbiology, Research

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

Posted on January 19, 2021 by | Leave a comment

Wiley Online

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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.

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Posted in Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Research

Research – Botulism breakthrough? Taming botulinum toxin to deliver therapeutics

Posted on January 17, 2021 by | Leave a comment

Science Daily

kswfoodworld

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 are often found 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 of botulism may need to be maintained on ventilators for weeks or months. But a new treatment approach and delivery vehicle, described today in Science Translational Medicine, could change that.

“There are anti-toxins, but these only work before the toxins enter the motor neurons,” says Min Dong, PhD, a researcher in Boston Children’s Hospital’s 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.”

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Posted in Bacterial Toxin, Biotoxin, botulism, Clostridium, Clostridium botulinum, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Toxin, microbial contamination, Microbiology, Research, Toxin

Research – Nanocrystals that eradicate bacteria biofilm

Posted on January 17, 2021 by | Leave a comment

Science Daily

The COVID-19 pandemic is raising fears of new pathogens such as new viruses or drug-resistant bacteria. To this, a Korean research team has recently drawn attention for developing the technology for removing antibiotic-resistant bacteria by controlling the surface texture of nanomaterials.

A joint research team from POSTECH and UNIST has introduced mixed-FeCo-oxide-based surface-textured nanostructures (MTex) as highly efficient magneto-catalytic platform in the international journal Nano Letters. The team consisted of professors In Su Lee and Amit Kumar with Dr. Nitee Kumari of POSTECH’s Department of Chemistry and Professor Yoon-Kyung Cho and Dr. Sumit Kumar of UNIST’s Department of Biomedical Engineering.

First, the researchers synthesized smooth surface nanocrystals in which various metal ions were wrapped in an organic polymer shell and heated them at a very high temperature. While annealing the polymer shell, a high-temperature solid-state chemical reaction induced mixing of other metal ions on the nanocrystal surface, creating a number of few-nm-sized branches and holes on it. This unique surface texture was found to catalyze a chemical reaction that produced reactive oxygen species (ROS) that kills the bacteria. It was also confirmed to be highly magnetic and easily attracted toward the external magnetic field. The team had discovered a synthetic strategy for converting normal nanocrystals without surface features into highly functional mixed-metal-oxide nanocrystals.

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Posted in Biofilm, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Technology

Research – Foods implicated in U.S. outbreaks differ from the types most commonly consumed

Posted on January 16, 2021 by | Leave a comment

Journal of Food Protection

Foodborne disease outbreak investigations identify foods responsible for illnesses. However, it is not known the degree to which foods implicated in outbreaks reflect the distribution of food consumption in the U.S. population or the risk associated with their consumption. To examine this, we compared the distribution of foods in 24 categories implicated in outbreaks to the distribution of foods consumed by the U.S. population. Beef, chicken, eggs, fish, herbs, mollusks, pork, sprouts, seeded vegetables, and turkey were implicated in outbreaks significantly more often than expected based on the frequency of their consumption in the general population, suggesting a higher risk of contamination or mishandling from foods in these categories than in others. In contrast, pasteurized dairy, fruits, grains-beans, oils and sugars, and root/underground vegetables were less frequently implicated in outbreaks than they were consumed in the general population, suggesting a lower risk for these food categories.

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Posted in food bourne outbreak, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbiology, outbreak

Research – Bacteria Broadly-Resistant to Last Resort Antibiotics Detected in Commercial Chicken Farms

Posted on January 16, 2021 by | Leave a comment

MDPI

Resistance to last resort antibiotics in bacteria is an emerging threat to human and animal health. It is important to identify the source of these antimicrobial resistant (AMR) bacteria that are resistant to clinically important antibiotics and evaluate their potential transfer among bacteria. The objectives of this study were to (i) detect bacteria resistant to colistin, carbapenems, and β-lactams in commercial poultry farms, (ii) characterize phylogenetic and virulence markers of E. coli isolates to potentiate virulence risk, and (iii) assess potential transfer of AMR from these isolates via conjugation. Ceca contents from laying hens from conventional cage (CC) and cage-free (CF) farms at three maturity stages were randomly sampled and screened for extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, carbapenem-resistant Acinetobacter (CRA), and colistin resistant Escherichia coli (CRE) using CHROMagar™ selective media. We found a wide-spread abundance of CRE in both CC and CF hens across all three maturity stages. Extraintestinal pathogenic Escherichia coli phylogenetic groups B2 and D, as well as plasmidic virulence markers iss and iutA, were widely associated with AMR E. coli isolates. ESBL-producing Enterobacteriaceae were uniquely detected in the early lay period of both CC and CF, while multidrug resistant (MDR) Acinetobacter were found in peak and late lay periods of both CC and CF. CRA was detected in CF hens only. blaCMY was detected in ESBL-producing E. coli in CC and CF and MDR Acinetobacter spp. in CC. Finally, the blaCMY was shown to be transferrable via an IncK/B plasmid in CC. The presence of MDR to the last-resort antibiotics that are transferable between bacteria in food-producing animals is alarming and warrants studies to develop strategies for their mitigation in the environment. View Full-Text

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Posted in Antibacterial, Antibiotic Resistance, antimicrobial resistance, Antimicrobials, E.coli, Enterobacteriaceae, ESBL, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Research, Technology