Research round-up: Online outbreak detective, bioelectronic ‘nose’ and Cyclospora
We start with scientists at the University of Massachusetts Amherst that have developed a rapid and low-cost method for detecting bacteria in water or food.
It can detect as few as 100 bacteria cells per 1 milliliter of solution, compared to a sensitivity of 10,000 cells for other rapid methods.
They designed a bacteria-detecting chip to test whether fresh spinach or apple juice, for example, carry a bacterial load.
The chip, used with a light microscope for optical detection, relies on a ‘capture molecule,’ 3-mercaptophenylboronic acid (3-MBPA) that attracts and binds to bacteria.
The chemical detection method, surface-enhanced Raman spectroscopy (SERS), relies on silver nanoparticles.
The standard method for culturing bacteria from food samples, known as an aerobic plate count (APC), takes two days.
Next, since 2012, 10 foodborne outbreaks have been identified thanks to a computer system created with Columbia University’s Department of Computer Science.
The system tracks foodborne illnesses based on certain keywords that appear in Yelp restaurant reviews. Twitter was added in November 2016.
It has helped New York Health Department staff identify 1,500 complaints of foodborne illness in New York City each year.
“Effective information extraction regarding foodborne illness from social media is of high importance. Online restaurant review sites are popular and many people are more likely to discuss food poisoning incidents in such sites than on official government channels,” said Luis Gravano and Daniel Hsu, co-authors of the study and professors of Computer Science at Columbia Engineering.
Researchers have developed a bioelectronic ‘nose’ that can detect a key decay compound at low levels.
When food begins to rot the smell comes from a compound called cadaverine. It is the result of a bacterial reaction involving lysine, which is an amino acid commonly found in various foods.
Researchers produced copies of the receptor in E. coli and assembled them into nanodiscs.
Receptor-containing nanodiscs were then placed in a special orientation on a carbon nanotube transistor, completing the bioelectronic nose.
During testing with purified test compounds and real-world salmon and beef samples, the nose was selective and sensitive for cadaverine even at low levels.
Dr Gerardo "Jerry" Lopez, an assistant professor and extension specialist in the University of Arizona's School of Animal and Comparative Biomedical Sciences in Tucson, is looking at Cyclospora prevalence in the US.
“We want to look at this because we don't know very much about Cyclospora and its prevalence in the US. We understand there have been these foodborne outbreaks associated with imports, but what are we doing that's different so we don't see it here?"
Samples of irrigation water, raw sewage and treated wastewater effluent are being tested in the Center for Produce Safety-backed work.
Knowing the genetic make-up of Cyclospora organisms could help researchers track them to their source. PCR assays will be run on all samples and TaqMan assays used.
The University of Arizona has received funding for a four-year project to develop safer and healthier cantaloupes.
The $610,000 grant is from the Specialty Crops Research Initiative (SCRI), a program of the USDA’s National Institute of Food and Agriculture.
In the past 10 years, melons have accounted for more than 40 outbreaks of foodborne illness across the US, according to the Centers for Disease Control and Prevention (CDC).
Sadhana Ravishankar, associate professor in the School of Animal & Comparative Biomedical Sciences of the UA College of Agriculture and Life Sciences, said the project aims to reduce bacteria on cantaloupes by improving food safety aspects of melon production.
Ravishankar will develop organic, plant-based sanitizers applied using fog tunnels and electrostatic sprays.
Current decontamination methods include chemicals - rinsing cantaloupes with chlorine - and organic methods such as dunking fruit in a scalding-hot bath (heat kills the bacteria but the bath introduces moisture that encourages mould growth).
Researchers hypothesize that a smoother rind will discourage microbes on the melon.
Texas A&M University are developing new breeds of cantaloupes with different rind textures and nutritional and antimicrobial properties from their predecessors.
Researchers have reviewed foodborne botulism outbreaks to describe clinical aspects and descriptive epidemiology to inform public health response strategies.
There were 197 outbreaks between 1920 and 2014 with the majority in the US (109/55%). Fatalities were reported in 115 (58%) outbreaks.
Toxin types A, B, E, and F were identified as the causative agent in 34%, 16%, 17%, and 1% of outbreaks, respectively. The most common food (n = 83, 42%) was a home-canned product.
Tohoku University students have provided a picture of canola oil's oxidation process by high performance liquid chromatography (HPLC) combined with tandem mass spectrometry (MS/MS).
Using the method, they identified specific oxidation compounds in canola oil resulting from heat (25-180°C) and light (office lighting-direct sunlight).
HPLC pumps liquid under high pressure through a granular adsorbent material to separate different components in the liquid.
MS/MS bombards the compound molecules separated by HPLC with neutral molecules (e.g. nitrogen) to break it apart into smaller components and measures the mass-to-charge ratio of the pieces.
Triacylglycerol (TG), a major component of edible oil, forms different oxidation compounds, or isomers, depending on how it is oxidized.
They found that marketed canola oil tends to be oxidized by light around room temperature. This suggests it should be packed in dark containers to extend shelf life by reducing light exposure.
A research project designed to track beef from paddock to plate has been launched at Queensland University of Technology (QUT).
Marcus Foth, Professor of Urban Informatics at the QUT Design Lab said BeefLedger is an industry-led project bringing together design, business, technology and food research.
“The BeefLedger Token (BLT) is being developed as part of the design and implementation of the world’s first application of distributed ledger or blockchain technology to the entire beef supply chain.
“If you are a consumer of Australian beef in China, Japan or elsewhere, then you are expecting a premium experience and not inferior meat being passed off as Australian, which has been the subject of recent food scandals.
“The BLT will power the BeefLedger Blockchain and provide users with the value-added benefits of access to credentialed provenance data, sale history, consumer feedback insights, disease prevention, streamlining payments, and heightened food security.”
Engineers at the University of Oxford have used material compounds, known as Metal Organic Frameworks (MOFs), to develop technology that senses and responds to light and chemicals.
Material changes colour depending on the substance detected. Opportunities for impact include: biosensors for safeguarding against food contamination and hand-held medical devices for non-invasive diagnosis and therapy.
The research was awarded the European Research Council (ERC) consolidator grant of €2.4m.
