Plasma proves effective at purging pathogens from fresh produce
Fresh food requires a bit of a balancing act to keep our bodies healthy. Fresh fruits and vegetables can be a great source of vitamins and fiber, but they can also carry unwanted bacteria. To deal with this, we can cook, irradiate or wash food in toxins to kill off the unwanted microbes, but often at the cost of the some of the health benefits of the food itself. What’s worse, some pathogens, like norovirus, often survive these treatments, leaving us with less flavor and nutrients but plenty of risk. A new cleaning process may improve greatly on these trade-offs, and all that it takes is exposing the food to conditions similar to the surface of the Sun.
Ions in every direction
The condition in question isn’t the Sun’s intense surface temperatures, but its existence in the state of matter called plasma. If a gas is composed of loosely affiliated molecules and atoms floating around, a plasma is basically those same atoms with enough extra energy to shake their electrons loose. This leaves you with a sort of cloud of positively charged protons zipping around independently of their negative electrons, which allows for some interesting properties not found in gases. While electrically negative as a whole, the free electrons can be used to conduct electricity, which is great if you want to make things like neon lights or plasma television screens light up. In the case of our fresh fruit, blasting blueberries with plasmic air is apparently great at wiping out pathogens like norovirus.
The plasma in this experiment was simply air with your usual assortment of oxygen, nitrogen, etc. When heated into a plasma though, the air glowed bright purple, and was hot enough that some cool air was added to the mix to avoid frying the blueberries being cleaned. The ionized air was then found to kill 99.99 percent of germs like norovirus, with no appreciable damage to the fruit itself. Part of this success was probably thanks to the fact that plasmic air would have enveloped every nook and cranny on the outside of the blueberry, although researchers admit that at this point they’re not sure what is actually doing the sanitizing. Figuring out if it’s the oxygen, nitrogen or other ions that is wiping out the germs will help researchers refine and expand this technology, with the hope that it can be used to safely clean fruit like blueberries on an industrial scale within three to five years.
Source: Healthier blueberries, thanks to a blast of purple plasma by Ula Chrobak, Science
