The truth is our ancestors only ate them for the following reasons, no refrigeration, they did not know the dangers of rancid food and they were hungry. Well we know the dangers, but at some time in the future, the other two reasons may apply to us.
Rancidity is a general term that refers to the spoilage of a food so that it becomes undesirable and usually unsafe for consumption. When we say that food has “gone bad,” what we are usually talking about is rancidity. Most of the time rancidity can change the odors or flavors of a food so that it becomes unpleasant to smell or taste.
While almost any food can become rancid, this term applies particularly to oils. Oils are specially susceptible to rancidity because of their chemistry, which can make them exceptionally subject to oxygen damage. When food scientists talk about rancidity, they are usually talking about a type of rancidity involving oxygen damage to foods. This type of rancidity is called “oxidative rancidity.” During the process of oxidative rancidity, oxygen molecules interact with the structure of the oil and damage its natural structure in a way that can change its odor, its taste, and its safety for consumption.
There are several ways to minimize rancidity in your storage.
- Opaque packaging and colored glass bottles will reduce light induced oxidative rancidity.
- Gas impermeable packaging such as Mylar bags will reduce the exposure of the product to oxygen.
- Free space in the container should be kept to minimum to reduce the amount of oxygen.
- Refrigeration or cold storage will reduce the rate of most reactions that produce rancidity. If no refrigeration is available, store in as cool an area as possible.
- Storing fat and oil rich foods in the dark will reduce the rate of photo-oxidation.
- Reducing the water level content of the foods by drying or smoking and then storing them away from moisture helps to reduce hydrolytic rancidity and discourage the growth of micro-organisms.
So what’s wrong with eating rancid oils?
At least several things, says lipid specialist and University of Massachusetts professor Eric Decker. “One is that they lose their vitamins, but they also can develop potentially toxic compounds” that have been linked to advanced aging, neurological disorders, heart disease and cancer”.
A 2002 study published in the journal Anticancer Research reported that rancid oils not only appear to be involved in tumor promotion but also in tumor initiation. This study was carried out on mice, and rancid corn oil was used as the source of spoiled fatty acids.
One of the problems with identifying rancid foods is that people ability to smell rancidity varies greatly. Some can smell small amounts, some can’t smell any period. If you have someone in your group with a good nose, trust it and avoid rancid foods whenever possible. That being said, most of us probably eat some rancid foods without realizing it. In a starvation situation, you may have to make the decision to eat rancid foods. But make the most educated decision possible and avoid rancid foods as much as possible.