Less oxygen means longer lasting organic produce

Photo: istockphoto.com/Kelly Cline
It turns out that pesticides and synthetic fertilizers aren't the only things that should be removed from organic food. The newest enemy of the organic farmer is oxygen. Due to its chemical-free nature, organic produce is notoriously hard to store for long periods of time. However, a new method of preservation that creates a low oxygen environment might solve that problem. Scientists in Israel treated Granny Smith apples for seven days with very low concentrations of oxygen at room temperature. The low oxygen level was achieved by pumping high levels of nitrogen into jars and then placing the apples in the jars. Normal air contains about 21 percent oxygen and 78 percent nitrogen, whereas these apples were exposed to less than 3 percent oxygen. After the pretreatment, the apples were then stored in a cooler at zero degrees Celsius for six to eight months with no scarring. Apples that weren't pretreated didn't last three months without heavy loss due to scarring. Edna Pesis, a researcher in the Department of Postharvest Science of Fresh Produce at the Volcani Center in Israel and lead author of the study, suggests that the reduced damage is due to decreased production of ethylene (a natural hormone that ripens fruit) and an increased production of acetaldehyde (a natural inhibitor for ethylene). The low oxygen treatment is an attempt to offer farmers alternatives to the very effective, but not organic, antioxidant diphenylamine (DPA). DPA can allow apples to stay perfectly preserved in cold storage for up to a year but there are many concerns about the toxic effects of this chemical. Pioneering this new treatment means that organic farmers could offer their produce at lower prices because less of their crop will be lost. Plus, it means that organic produce could be stored for longer amounts of time, so you can get organic produce in the winter. Edna Pesis is also studying ways to organically preserve other fruits and vegetables such as mangoes, avocado, and tomatoes. The research was done in collaboration with partners in Kazakhstan, one of the largest growers of apples and the "birthplace of apples" where supposedly the first apples were grown. Graeme Stemp-Morlock B.Sc. is a freelance science writer.