Biochemists and engineers at the McMaster University have developed a new patch technology that can help prevent humans from consuming contaminated food.

Food spoilage is caused by the contamination of bacteria like E. coli and salmonella. The Shiga toxins produced by E. coli can lead to diarrhea, fatal respiratory illnesses, pneumonia, and even death.

The World Health Organization estimates that about 10 percent of patients with Shiga toxin-producing E. coli infection may develop hemolytic uremic syndrome, a serious disease brought by the E. coli strain. About three to five out of 10 patients are most likely going to die due to complications such as acute renal failure, severe anemia, and thrombocytopenia or low blood platelets.

The most potent source of E. coli is the consumption of raw or undercooked meat as well as contaminated milk. Pathogens breed in livestock animals like cattle, sheep, goats, and deer, and then transferred to humans when they are shipped to supermarkets and wet stores.

The Test Patch

To address this, a team of engineers from McMaster University partnered with chemists in the campus to develop a test patch that can determine if harmful bacteria are present in food.

This technology, which was published in the journal ACS Nano, aims to replace the traditional expiry date stamped on food packages. Expiry dates are often unreliable especially if there are problems with proper food storage, according to the Department of Health and Human Services in Victoria, Australia.

"In the future, if you go to a store and you want to be sure the meat you're buying is safe at any point before you use it, you'll have a much more reliable way than the expiration date," said Hanie Yousefi, lead author and a graduate student at the Faculty of Engineering.

The patch, called the Sentinel Wrap, is transparent and measures less than an inch in width. Ideally, food manufacturers would place the patch inside the food package and anyone can test its freshness or contamination using a smartphone or a simple portable device.

"When the bacteria are present, if you put it into the packaging, you can actually see the presence of those dots. They shine up, compared to the samples that do not have the bacteria present in them," said Tohid Didar, a mechanical-biomedical engineer and also an assistant professor at McMaster Institute for Infectious Disease Research.

The team also collaborated with biochemist Yingfu Li to develop the signaling technology that will detect the existence of pathogens on the food above the reasonable level.

The Sentinel Wrap can help manufacturers, sellers, and consumers check food safety without necessarily going to a lab for proper testing.

Although mass production of the patch will be relatively cheaper compared to other technologies, the Sentinel Wrap would need the approval of private and government entities in order to be rolled out in the market for large-scale use.

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