I have some oil for deep frying -- used only once -- that has been in the
eight months. Can I still use it? - Barbara Leonard (4/19/01)
We use vegetable and canola oil in our home for cooking. I'm disabled
and on a very small budget and would appreciate any advice about
cleaning the oil for re-use, hopefully to remove sediment, discoloration
and odor. Thank you. - Mike and Brenda (11/05/06)
never reuse cooking oils. The foods you cook the oils in will cause the oils to go rancid faster.
A recent study found
that a toxin called 4-hydroxy-trans-2-nonenal (HNE) forms when such oils
as canola, corn, soybean and sunflower oils are reheated. Consumption of
foods containing HNE from cooking oils has been associated with
increased risks of cardiovascular disease, stroke, Parkinson'?s disease,
Alzheimer's disease, Huntington's disease, various liver disorders, and
cancer. Once absorbed in the body, HNE reacts with DNA, RNA and proteins
affecting basic cellular processes.
Reusing cooking oil
has been done for ages. There really isn't a problem, if done properly.
The greatest hazard is allowing the fat to become rancid (spoiled) and
deteriorated to the point it produces undesirable flavors and odors.
Besides ruining what would have been a perfectly good meal, rancid oils
also contain free radicals that are potentially carcinogenic. Rancid oil
has fewer antioxidants but is not poisonous.
To re-use oil
safely, use these tips:
Strain it through a few layers of
cheesecloth to catch any food particles. Be careful with hot oil,
though, because you can easily get burned.
Shake off excess batter from food
before frying it.
Use a good thermometer to fry foods
Turn off the heat after you are done
cooking. Exposing oil to prolonged heat accelerates rancidity.
Don't mix different types of oil.
Store oil in a cool, dark place.
Avoid iron or copper pots or pans for
frying oil that is to be reused. These metals also accelerate rancidity.
Signs of Deteriorated Oil:
Oil darkens with use
because the oil and food molecules burn when subjected to high/prolonged
The more you use an
oil, the more slowly it will pour. Its viscosity changes because of
changes to the oil's molecular structure.
particles accumulate as sediment at the bottom of the storage container
or are suspended in the oil.
When smoke appears on
the oils' surface before the temperature reaches 190 degrees C (375
degrees F), your oil will no longer deep-fry effectively.
If the oil has a rancid
or "off" smell or if it smells like the foods you've cooked in it, it
should be discarded.