Does fish oil last like any other oil?

August 13, 2007 3:08 PM

Does fish oil last like any other oil?

I've got a jar of deep sea salmon fish oil complex soft gels which I've neglected in my dorm for 2 weeks under the summer heat (room 30-38 degrees celsius). I've only recently recovered from self-applied food poisoning and the fish oil is a suspect.

So my question is, does fish oil last under these temperatures over long periods of time? Does it last just like any other oil, like sesame oil? If not, how can I tell whether it has become inedible?

Additional info: looks and smells the same, produced in September last year, label suggests it should last 3 years.

posted by gttommy to food & drink (6 comments total)

Fish oil goes rancid due to oxidation. The capsules will oxidize faster at higher temperatures so it's possible it's starting to go bad. Break open the capsules and smell/taste the oil. If it's repulsive, it's obviously gone bad. Unoxidized fish oil shouldn't have too strong of a taste.

Rancid fish oil is unlikely to cause food poisoning, though. It'll probably just give you nasty smelling burps.
posted by Durin's Bane at 3:15 PM on August 13, 2007

Actually, even fresh and clean fish oil will cause pretty strongly fish-smelling burps.
posted by luriete at 4:03 PM on August 13, 2007

Fish oil can cause burps no matter what, which is why you want the enteric coated kind to help prevent it.

Keep fish oil in a cool dark place, ie the fridge, and you'll be fine.
posted by rsanheim at 5:42 PM on August 13, 2007

Freeze it. It should keep better and minimize the burps.
posted by 4Lnqvv at 5:56 PM on August 13, 2007

Pure fish oil is pretty sensitive to light and heat. It will go rancid in poor storage conditions. When very rancid, it will taste and smell very unpleasant. When a little rancid, it will taste and smell "off". Since the point of taking oil supplements is to get "good" oils into your system, don't take it even if it's only a little off.

Caps that weren't exposed to light are probably ok even if they were warm, if air hasn't made it in through the cap coating.

Rancid oil might make you feel a bit sick but I can't see it causing food poisoning per se. The microbes that cause food poisoning don't grow in oil; they need a moist medium with appropriate nutrients.
posted by i_am_joe's_spleen at 7:30 PM on August 13, 2007

Unsaturated fats go bad faster than saturated fats. (That's why the processed food industry used to hydrogenate vegetable oils; hydrogenated oil lasts longer.)

Your pills won't make you sick, but they may no longer do for you what you want them to do. The Omega-3's probably aren't Omega-3 any longer.
posted by Steven C. Den Beste at 7:31 PM on August 13, 2007