Preventing Food Poisoning With An Old Biopesticide
A Science Enthusiast
Even in the cleanest and most stringent of countries, outbreaks of illness still occur every now and then from some contaminated food source.
This isn’t surprising, though, as there are so many parts of the food processing pipeline, from farm to store shelf where contamination can occur. Even uses of preservatives and anti-bacterials, of which luckily salt is both, can only go so far.
Bacteria on their own continue to try and find ways to infect and attack crops, even beyond our precautions. This will, in turn, lead to someone ingesting some food source contaminated with said bacteria and getting sick from it.
So one of the primary focuses in food science is discovering new and better options to fight against bacteria, including new chemical sources that prevent their spread. And that’s what today’s topic is about.
Clostridium perfringens is a fairly dangerous bacteria, ranking third in the US and UK for food illness outbreaks. Depending on one’s own immune system and the particular conditions of infection, the illness can have no negative effects at all and pass easily. Or, it could steadily become worse and worse with symptoms of necrosis and gangrene, eventually resulting in full blown clostridial myonecrosis.
This condition is life-threatening and the treatment is often outright amputation of the infected limb or outright incision and removal of tissues in other areas. While this result of infection from the bacteria is rare, it still happens to around 1000 people a year in the US, far higher an amount than is comfortable.
In most cases, C. perfringens just leads to more minor symptoms of fever, diarrhea, vomiting, and severe pain, leaving in just over 24 hours. If you consider that a better state of affairs than amputation, then I would agree with you, but it’s still not a fun time overall.
The Usefulness of Chitosan
So, as you might expect, prevention of bacteria like C. perfringens is top priority for food safety scientists and workers. Researchers from Oregon State University have been studying an anti-bacterial substance directly primed against the bacteria known as Chitosan.
This isn’t a new chemical. It’s been in use in agriculture for several decades as an anti-fungal biopesticide. It has also seen direct anti-bacterial use in medicine and for its uses as a skin-permeable drug delivery system.
For the purposes of their experiment, they used chitosan obtained from one of its primary sources, crustacean shells, and exposed it to C. perfringens at different levels of activity. This included the spore form of the bacteria when it is dormant and hard to attack and kill.
Food Poisoning Inhibition
The bacterial spores were inserted into chicken meat and then treated with chitosan at different dosage levels. What the researchers found is that the polysaccharide chemical was capable of preventing germination of the spores, along with stopping growth of active vegetating cells of the bacteria.
The only downside from the experiment is that the doses required in the petri dish did not match up to tests in chicken meat, where a significantly higher dose of chitosan was required to inhibit the spores.
This difference was significant, going from about 0.1 or 0.25 mg/ml to 2.0 mg/g (the ml to g switch due to the change from a liquid to solid environment). Sometimes even a dose of 3 mg/g was required for it to be effective.
While this is somewhat of a limiting factor, this dosage requirement remains below levels of actual difficulty and is still a capable amount to be used in food production. This effectiveness against C. perfringens is the first time such a capability has been shown from the chemical and is perhaps a turning point in the fight against the third most common food illness outbreak in the US.
Other Avenues And Combinations
The next step the researchers will be taking is testing chitosan on other meats to see if the doses remain the same or need to be adjusted. Similarly, they want to test the chemical in combination with other inhibitory preservatives, like sodium benzoate, to see if a combined effect could prove to have a stronger outcome and also lower the amount of chitosan needed.
Overall, chitosan looks to be a huge step forward in food safety research and may save hundreds of lives, along with protecting the health of thousands of people.
Photo CCs: Chicken – Kolkata 2011-02-11 1007 from Wikimedia Commons