I have heard that one shouldn't reheat a meal with spinach in it. Is there any truth in this and what is the reason?
Reheating spinach can cause nitrite to be produced. Quote from eufic.org
Spinach and other leafy vegetables contain high concentrations of nitrate. The amount depends on the variety, season, and the soil and water conditions where the vegetable was grown. Nitrate itself is totally harmless, but it can be converted to nitrites, and then to nitrosamines, some of which are known to be carcinogenic. Enzymes present in bacteria convert nitrate to nitrite. This happens especially when spinach is heated, stored and then later reheated. Nitrite itself is a harmless compound, but it should be avoided by infants of up to 6 months. It can affect the ability of the blood to transport oxygen by transforming haemoglobin, the protein that carries oxygen in the blood, into methaemoglobin, a form of the protein which is unable to carry oxygen. This can be dangerous for babies and is commonly known as “Blue Baby Syndrome”. However, in view of the fact that acidic conditions favour the formation of nitrosamines from nitrite, coupled with the facts that nearly all foods contain some protein and are exposed to acid in the stomach nitrosamine production cannot completely be prevented. Hence the recommendation to avoid reheating spinach.
1Great answer. I'd love to see numbers attached - I suspect that's a case of the EU being massively overcautious.– ceejayozJul 20, 2010 at 12:42
Probably true... Jul 20, 2010 at 12:56
1Even so, this would only apply if the spinach dish had a significant bacterial presence. If it is refrigerated after it is cooked, there shouldn't be significant bacterial growth. Seems far fetched. Jul 20, 2010 at 15:04
3EUFIC changed their recommendation a few years ago, since it was based on outdated and inadequate numbers. Their website seems no longer to contain any of these recommendations at all, but the Independent article describing the reason behind the removal of this recommendation is still available. Feb 23, 2019 at 16:39
"It is also safe to eat leftover leafy greens like spinach as long as they are thoroughly reheated." – eufic.org/en/food-safety/article/… Feb 24, 2020 at 21:22
As others have said, reheated spinach may contain small amounts of nitrites. These are harmless to adults and children over 6 months, but dangerous for young infants. The upshot is: if you're not serving it to young infants, it should be fine.
This is what I read too, in a newspaper reporting current research. It added that you still should heat it a lot of times, and you shouldn't do it every day, but that the average person shouldn't worry about it.– CerberusAug 28, 2012 at 22:39
I can think of no reason other than taste.
I've reheated numerous spinach dishes in the past, with no apparent detrimental effects to my health.
Spinach doesn't have any special properties that other greens like beet greens, collards, mustard greens, etc. don't have, so I don't see any reason why spinach would be special in this respect.
Like most greens, it doesn't react well to being overcooked, so when reheating, stir often, and you should be fine.
"with no apparent detrimental effects to my health" Just because my grandpa smoked like a chimney and is still going strong at 80 years old...– LucOct 29, 2019 at 17:27