From analytical techniques for food fraud, traceability management strategies, heat-resistant E. coli concerns, biosensor and bacteriophage work we see what the world of research has for us this time.
We begin work University of Alberta researchers, who have found that cooking ground beef at 71C - the level advised by Health Canada - does not always eliminate all strains of E. coli.
“We’ve been hammering consumers for years to cook chicken properly, to handle it properly, and to do the same with ground beef but still we seem to have these outbreaks of E. coli (attributed to hamburgers),” said Lynn McMullen, a food microbiologist in the Department of Agricultural, Food and Nutritional Science.
“Does this explain why? It might.”
They discovered 16 genes found only in the highly heat-resistant strains of E. coli under wet conditions (i.e. fresh meat). This genomic grouping is called the locus of heat resistance (LHR).
After looking at genome databases for LHR, they saw it exists in about 2% of all E. coli in the databases and is in the harmless and pathogenic strains.
Since UAlberta’s bacterial strains were all non-pathogenic, the team is working with Health Canada and the Alberta Livestock and Meat Agency, to access cultures from other collections across the continent.
They are now searching for how prevalent this problem of occasional survival is across strains and other bacteria closely related to E. coli.
Next, University of Notre Dame work has revealed that a firm's ability to trace products varies based on contextual factors.
They said traceability is hindered by temporality (i.e., time pressures that strain a firm's ability to track products), supply chain permeation (i.e., supply chain flow characteristics that represent the degree of bad product infiltration), and product information ambiguity (i.e., product characteristics that create vagueness about what to trace).
Kaitlin Wowak, assistant professor of management at Notre Dame’s Mendoza College of Business, said traceability should be managed differently depending on the product’s perishability.
“Our research reveals a downside to supply chain initiatives that stress pushing products to market too quickly. Thus, firms should consider adopting different traceability requirements for fast-flowing products.
“Federal regulations mandate that firms have traceability one step up and down the chain. However, this may not be sufficient for perishable products that flow quickly, such as fresh strawberries or dairy products.
"If firms develop traceability two or three steps up and down the chain, they may have access to more information, which could help the product and information flow in unison and mitigate information gaps, which are particularly detrimental during product recalls.”
Wowak said product ID changes due to blending can distort information, making traceability more difficult.
“Product blending is when you physically mix raw ingredients to produce a product. Take salsa, for example. Its tomatoes and jalapeno peppers each come in with separate IDs. We mix them together and we get a new ID. The new ID is what hinders traceability.
“Firms should consider giving products that are blended or co-mingled a new ‘nickname’. This would allow the original ID to follow the product down the chain and reduce the extent to which information is distorted.”
AMS applied to food fraud
Meanwhile, Connor Black et al said there has been rapid growth of ambient mass spectrometry (AMS) with more than thirty different ambient ionisation techniques available.
A number of these techniques such as DART, DAPCI, EASI, LESA and PS coupled with mass spectrometry have enhanced the way in which the detection of food adulteration is done, they said.
Methods of detection include spectroscopic techniques such as ultraviolet-visible (UV), mid infrared (MIR), near infrared (NIR), Fourier transform infrared (FT-IR), Raman, fluorescent; nuclear magnetic resonance (NMR); isotope ratio mass spectrometry (IRMS); inductively coupled plasma mass spectrometry (ICP-MS); proton transfer reaction-mass spectrometry (PTR-MS); high performance liquid chromatography (HPLC) and gas chromatography (GC).
Mass spectrometry techniques coupled with chromatography such as liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS); electronic nose; DNA based technologies such as polymerase chain reaction (PCR); immunological technologies such as enzyme-linked immunosorbent assay (ELISA) and thermal techniques such as differential scanning calorimetry (DSC) have also been used.
However, most require long and complex sample preparation and assay times.
Conventional and AMS techniques are providing similar qualitative results with regards to detecting food fraud but AMS-based ones require minimal to no sample preparation and have fast assay running times compared to conventional methods.
However, in terms of quantitation there are still issues concerning how accurate the results are and the possibility for false negatives and positives. Perhaps the biggest drawback for AMS is that it is not possible to achieve quantification of solid samples, they said.
Electronic sensor development
In other news, an electronic sensor to detect and classify bacteria for food safety has passed a key hurdle by distinguishing between dead and living bacteria cells.
The approach might be used to create arrays of hundreds of sensors on an electronic chip, each sensor detecting a specific type of bacteria, said researchers at Purdue University.
The sensor works by detecting changes in electrical conductivity in droplets containing bacteria cells.
Muhammad Ashraful Alam, Purdue University's Jai N. Gupta Professor of Electrical and Computer Engineering, said: “To see if someone is alive we can either count the grandchildren many generations later, which is analogous to the traditional growth-based techniques.
“Or, we can directly measure the person's pulse, analogous to the proposed 'osmoregulation-based' detection of bacteria. Needless to say, immediate physiological measurement is faster and far superior."
Bacteriophages used to reduce Salmonella
Research from the University of Nevada, Reno saw treated meat products infected with four types of Salmonella by applying Myoviridae bacteriophages during mixing.
Bacteriophages are viruses that only harm specific bacterial cells and are harmless to humans, animals and plants.
Amilton de Mello, assistant professor from the College of Agriculture, Biotechnology and Natural Resources at the university, said they were able to reduce Salmonella by as much as 90% in ground poultry, ground pork and ground beef.
"On the final ground meat products, there was a 10-fold decrease of Salmonella. The results are very encouraging and we're hoping this can be adopted by the meat industry to increase food safety."
Salmonella was inoculated on refrigerated meat and poultry trim, then the treatment was applied before grinding.
He presented the work at the international American Meat Science Association's conference in Texas.
Portable biosensor development
Finally, Washington State University researchers have developed a portable biosensor that is able to detect and amplify the signal of E. coli O157:H7.
Researchers developed a particle at nanoscale that includes organic and inorganic components and looks like a tiny flower to maintain a large amount of enzyme activity for detecting antigens in a sample.
Yuehe Lin, professor in the School of Mechanical and Materials Engineering, said: “We want to take these nanoflowers and create a simple-to-use, handheld device that anyone can use anywhere. It’ll be as simple as using a pregnancy test strip or a glucose meter.”
The researchers have filed a patent for the handheld device concept and are working on components of the nanoflower to detect disease markers and other pathogens such as Salmonella.
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