Research round-up: Allergen detection and detecting spoilage

We start with a look at researchers that have developed a portable allergen-detection system​​ - including a keychain analyser.

Avoidance isn't always possible because food can be mislabeled or cross-contaminated. Conventional methods of detection either require lab equipment or are slow and don't pick up low concentrations.

Researchers developed a $40 portable allergen-detection system called integrated exogenous antigen testing (iEAT).

It consists of a handheld device to extract allergens from food and an electronic keychain reader for sensing allergens that wirelessly communicates the results to a smartphone.

In less than 10 minutes, the prototype could detect five allergens, one each from wheat, peanuts, hazelnuts, milk and egg whites, at levels lower than the gold standard lab assay.

Building a prosecution case​

Researchers have looked at how molecular typing​​ can help present a case for prosecution against restaurants which pose a public health risk.

Fifteen cases of Salmonella enteritidis had the same multiple locus variable-number tandem repeat analysis (MLVA) profile as environmental and food samples from an implicated restaurant.

Adenosine triphosphate hygiene swab tests and data loggers provided evidence of poor quality cleaning procedures.

A case for prosecution was built and the FBO was successfully prosecuted in July 2015.

Silvana Andreescu, a Clarkson University Professor​, has developed a sensor to spot spoilage.

The ‘smart label’ is a low-cost, portable, paper-based sensor that can determine when food spoils and took about ten years to develop.

It works through the use of nanostructures as the sensors catch and bind the pre-determined compounds to distinguish change.

“If the target is present the color or electrical current changes. These changes indicate if the compound is present and in what quantity, and if there are changes in the initial composition,” ​said Andreescu.​

The team is working on the second generation sensors to extend the application range to include pesticides, adulterants and markers for freshness or spoilage.

A team in a University of Connecticut lab​ has processed 4,000 mangoes and water samples to test the efficacy of three disinfectants commonly used by industry to avoid contamination.

They found chlorine was extremely effective. The Center for Produce Safety and the National Mango Board funded the work.

MMWR studies​

US researchers investigated a Clostridium perfringens​​ outbreak at a catered lunch in Connecticut in September 2016.

Among 50 attendees, 30 completed the survey and 19 respondents met the case definition.

Analysis of food exposures reported by 16 ill and 10 well respondents found illness to be associated with the beef dish.

C. perfringens outbreaks are typically associated with improper cooling or inadequate reheating of contaminated meats.

Stool specimens from four food workers and four ill attendees tested negative for norovirus, Campylobacter, E. coli O157, Salmonella and Shigella at the Connecticut State Public Health Lab.

At the Minnesota Department of Health Public Health Lab two specimens from food workers were positive for enterotoxigenic E. coli by PCR but no enterotoxigenic E. coli colonies were isolated.

Seven specimens (four from food workers and three from attendees) were culture-positive for C. perfringens and specimens from all attendees contained C. perfringens enterotoxin.

Pulsed-field gel electrophoresis did not identify the C. perfringens strain responsible for the outbreak.

Other US researchers looked at six cases of domestically acquired, non-toxigenic Vibrio​ cholerae​​ infections in Minnesota in August 2016 likely from eating shrimp at a restaurant.

The isolate was identified as serogroup O1, serotype Inaba at Minnesota Department of Health (MDH).

Shrimp from India samples yielded V. cholerae non-O1, non-O139, but V. cholerae O1 was not isolated.

The outbreak included the first V. cholerae O1 case identified in a non-traveller in Minnesota since such surveillance began in 1996.

A study looked at an outbreak of Campylobacter jejuni​​ associated with undercooked chicken liver mousse in Clark County in Washington in 2016.

Five cases (three confirmed and two probable) were identified after eating at a restaurant.

The sous-chef used the appearance of the chicken liver mousse alone to determine whether they were fully cooked.

Final internal cook temperature of the largest liver measured by an inspector was <130°F (54°C), below the minimum 165°F (74°C) internal temperature deemed necessary by the Food and Drug Administration.

The PFGE pattern from a patient stool specimen isolate was indistinguishable from two chicken liver samples collected in a 2014 campylobacteriosis outbreak in Oregon. Chicken livers associated with the 2014 and this outbreak were supplied by the same company.

Research grants​

Improving the US melon industry is the subject of work by scientists from Texas A&M​ AgriLife Research and in seven other states.

A grant of more than $4.4m will drive the work, provided by the US Department of Agriculture's National Institute of Food and Agriculture, and is part of $35m given to 12 projects.

Dr Bhimu Patil, director of AgriLife Research's Vegetable and Fruit Improvement Center in College Station, said that since 1990 cantaloupes have been associated with 36 US foodborne disease outbreaks and pathogen-based recalls predominantly linked to Salmonella.

Research will focus on cantaloupe and honeydew because the surface area of these fruits are harder to wash and pathogens can accumulate on the outside and contaminate the flesh when cut.

A $20m award from the National Science Foundation will help universities across Alabama​ collaborate to better understand interactions of plasmas that could lead to development of new technologies in areas such as food safety.

The five year project will improve understanding of plasma processes and interactions.

Yogesh Vohra, professor and university scholar in UAB’s Department of Physics, is the UAB lead on the project and serves as co-principal investigator for the research.

“This research infrastructure improvement project will also enable improved laser diagnostics capabilities for existing UAB plasma reactors, as well as provide funding for developing next-generation technologies of large area plasma technologies needed for manufacturing.” ​

UAB will work with Alabama A&M University, Alabama State University, Auburn University, Oakwood University, Tuskegee University, University of Alabama, University of South Alabama and University of Alabama at Huntsville.

In another study, Patrick Cullen et al​​ discuss the status and challenges of transferring cold plasma technology to the industry.

Major challenges for adoption of atmospheric plasma as a food processing tool by industry are demonstration of product/process specific efficacies;  development of process compatible technology designs and scale-up; effective process control and validation; regulatory approval and consumer acceptance.

The Abdul Latif Jameel World Water and Food Security Lab​ (J-WAFS) at MIT has awarded commercial grants in food and water.

Sanjay Sarma has been awarded a commercialization grant to develop a handheld device that can test the quality of milk by measuring milk fat and protein.

The team will develop and test the image processing system behind their technology. Once refined, they will turn it into a sensor scaled for handheld devices and conduct pilot studies in India.  

Timothy Swager and postdoc Myles Herbert​​ will follow up prior funding to further refine a technology that exploits the chemistry of Janus emulsions.

Janus emulsions are special droplets on the nano scale that have two or more distinct physical properties.

Swager and Herbert have developed a process in which Janus particles interact with bacteria to detect foodborne pathogens and the interaction between the liquid droplets and bacterial proteins can be detected by a smartphone.