New Bacteria-Detecting Strip May Be Able To Detect E. coli


We all know that we can’t tell if a food is contaminated with something like E. coli or salmonella just by looking at it. But, wouldn’t it be nice if we could? Scientists are now finding ways to tell if a food is contaminated just by looking at the plastic packaging.

Scientists and researchers at McMaster University in Hamilton, Ontario are figuring out this process. They have developed Sentinel Wrap, a thing plastic patch. The patch changes colors when it is under ultraviolet light whenever it comes in contact with meat contaminated with E. coli. McMaster chemical and mechanical engineering department professor, Tohid Didar says it “took 15 years of research to get it to work”.

  1. coli is a common foodborne bacteria that in found in the intestines of humans and animals. Certain strains of the bacteria can lead to severe food poisoning, especially in elderly adults, young children, and those with a weakened immune system. E. coli is commonly found in meats, but it can be found in other food products as well. It is important to properly wash foods at all time. It is also important to cook foods at their proper temperature, avoid cross contamination, and safely store them. Taking precautions may prevent E. coli poisoning, but it is not guaranteed.

The patch is about the side of two postage stamps. Tohid is quoted saying, “This could be the wrap that you wrap around your meat,” proving its flexibility. You can then scan the food to see if the meat, or other food item, is contaminated or not. The piece of plastic is created by taking tiny drops of DNA molecules and plastic them on the flexible film. Once the patch comes into contact with E. coli, and is place under ultraviolet light, the DNA molecules light up. That lets scientists, and consumers of the future, that there is a presence of bacteria.

Other methods used to test for presence of E. coli is a multi-step process that can take at least a day, as Didar explains. “You need to take the page, open it, process it, take it to the lab, either culture that sample or try to do a different laboratory-based experiments to find out what is going on”.

Carlos Filipe, a team and chair member of McMaster’s chemical engineering department, shares a future hope involving the plastic. He hopes that one day, consumers will be able to use their smartphones to tell them if a food is contaminated or not, by pointing their camera at it through an app. He says, “The goal is to allow people to ultimately look at the packaged food and be able to tell if there is food contamination, like E. coli, in that food, without having to open the package”.

The team is also working to develop Sentinel Wrap patches used to detect contamination of salmonella, listeria, and other types of foodborne illnesses. The patches are also able to detect contamination in water, and other liquids.

Didar assures everyone that Sentinel Wrap is safe, and will not contaminate food. They have made a major breakthrough, but still have to overcome some other obstacles before they begin using and testing the patch in the real world, and with consumers. Regulators still need to approve of the patch, followed by the researchers bringing down Sentinel Wrap’s price. “We are hoping that in two years’ time, with the industry partners that we are currently talking to, we can at least start some pilot studies on these so that we can have some selected food in grocery stores that we can follow and see what happens,” Didar states.

In the meantime, consumers should immediately report any signs or symptoms of E. coli to their healthcare professional, to avoid serious or fatal results.


  • E. coli Symptoms:


  • Diarrhea, which may range from mild and watery to severe and bloody
  • Abdominal cramping, pain or tenderness
  • Nausea and vomiting, in some people

Symptoms can begin as soon as a day, or up to a week after consumption of the bacteria.

Leave a Reply