# Are parsley and spinach dangerous to reheat? **URL:** \ **Category:** Factual Questions\ **Created:** [April 3, 2004, 6:54pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086 "2004-04-03T18:54:49Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Takeo\_Jr](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@Takeo\_Jr](https://boards.straightdope.com/u/Takeo_Jr)\ **Post date:** [April 3, 2004, 6:54pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/1 "2004-04-03T18:54:49Z")
I am an American living in Denmark, and there is a general belief that foods with parsley in it cannot be reheated and eaten safely, as parsley becomes poisonous (?) when reheated. Ditto for spinach and cilantro. People here take this quite seriously, my ex worked in a Kindergarten where they were strictly forbidden from serving hot food containing either parsley or spinach. I simply don’t believe this is true. What about canned spinach? That’s cooked, and then you are supposed to reheat it. Please settle this for me once and for all! Breathlessly awaiting enlightenment on this, TJ ---
**Author:** ![newcrasher](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@newcrasher](https://boards.straightdope.com/u/newcrasher)\ **Post date:** [April 3, 2004, 6:59pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/2 "2004-04-03T18:59:51Z")
It is widely known that spinach, cilantro, parsley as well as broccolli, rhubarb and orange chutney are highly explosive when heated above 122 degrees f. Please heat these products with care. ---
**Author:** ![Takeo\_Jr](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@Takeo\_Jr](https://boards.straightdope.com/u/Takeo_Jr)\ **Post date:** [April 3, 2004, 7:08pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/3 "2004-04-03T19:08:18Z")
> [@newcrasher](#): > > It is widely known that spinach, cilantro, parsley as well as broccolli, rhubarb and orange chutney are highly explosive when heated above 122 degrees f. > > Please heat these products with care. That may be the case, but not at all what I’m talking about or what these Northerners are living in fear of- apparently, reheating, that is, heating ALREADY cooked parsley, cilantro or spinach makes it, well, POISON. No explosions, no mechanical dangers like that. POISON. Hope this was de-obfuscating TJ ---
**Author:** ![Torpor\_Beast](https://avatars.discourse-cdn.com/v4/letter/t/71e660/32.png) [@Torpor\_Beast](https://boards.straightdope.com/u/Torpor_Beast)\ **Post date:** [April 3, 2004, 7:21pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/4 "2004-04-03T19:21:24Z")
> [@Takeo Jr](#): > > That may be the case, but not at all what I’m talking about or what these Northerners are living in fear of- apparently, reheating, that is, heating ALREADY cooked parsley, cilantro or spinach makes it, well, POISON. No explosions, no mechanical dangers like that. POISON. > > Hope this was de-obfuscating > > TJ I’m pretty sure this is just one more stupid health scare like the one several years back when people claimed that microwaving plain water made it carcinogenic. I think you’ll find plenty of guinea pigs like me who’ve eaten re-heated parsley, spinach etc. serveral times and are still breathing. Then again you’ll just have to trust me when I say I’m not undead… 😃 ---
**Author:** ![cabdude](https://avatars.discourse-cdn.com/v4/letter/c/58956e/32.png) [@cabdude](https://boards.straightdope.com/u/cabdude)\ **Post date:** [April 3, 2004, 7:23pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/5 "2004-04-03T19:23:22Z")
The only reference I can find is a danger of shigellosis food poisoning from raw, uncooked parsley. It’s not the parsley _per se_ that causes the food poisoning but the contaminated water sitting on the parsley leaves. I would have thought that heating the leftovers decrease the danger of food poisoning rather than increase it. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [April 3, 2004, 7:28pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/6 "2004-04-03T19:28:07Z")
The issue is that safe shelf life for these veggies after being cooked and saved is a paltry 48 hours. They only keep for 48 hours…and… …to make matters worse, they reheat extremely quickly, so any bacteria that has made itself at home won’t be presented with heat above 140 degrees F…and if they do reach 140 at rehating, it won’t be for long since they reheat so quickly, increasing the odds that bacteria will survive. So, it is very easy to keep these foods past their shelf life after initial heating, and when you do get around to reheating them, you might have gone past the 48 hours. And to make matters worse, they reheat so fast that bacteria might not be killed. That’d be the dangers. ---
**Author:** ![cabdude](https://avatars.discourse-cdn.com/v4/letter/c/58956e/32.png) [@cabdude](https://boards.straightdope.com/u/cabdude)\ **Post date:** [April 3, 2004, 7:35pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/7 "2004-04-03T19:35:11Z")
> [@Philster](#): > > The issue is that safe shelf life for these veggies after being cooked and saved is a paltry 48 hours. > > They only keep for 48 hours…and… > > …to make matters worse, they reheat extremely quickly, so any bacteria that has made itself at home won’t be presented with heat above 140 degrees F…and if they do reach 140 at rehating, it won’t be for long since they reheat so quickly, increasing the odds that bacteria will survive. > > So, it is very easy to keep these foods past their shelf life after initial heating, and when you do get around to reheating them, you might have gone past the 48 hours. And to make matters worse, they reheat so fast that bacteria might not be killed. > > That’d be the dangers. OK - but who reheats parsley or spinach on their own? What about reheating foods that CONTAIN parsley or spinach? The act of reheating them wouldn’t necessarily render tham poisonous. ---
**Author:** ![Takeo\_Jr](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@Takeo\_Jr](https://boards.straightdope.com/u/Takeo_Jr)\ **Post date:** [April 3, 2004, 7:46pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/8 "2004-04-03T19:46:34Z")
> [@Philster](#): > > The issue is that safe shelf life for these veggies after being cooked and saved is a paltry 48 hours. > > They only keep for 48 hours…and… > > …to make matters worse, they reheat extremely quickly, so any bacteria that has made itself at home won’t be presented with heat above 140 degrees F…and if they do reach 140 at rehating, it won’t be for long since they reheat so quickly, increasing the odds that bacteria will survive. > > So, it is very easy to keep these foods past their shelf life after initial heating, and when you do get around to reheating them, you might have gone past the 48 hours. And to make matters worse, they reheat so fast that bacteria might not be killed. > > That’d be the dangers. Thanks Philster! That’s the first illuminating thing anyone has said to me concerning this. A couple of thoughts: I assume your 48 hour scenario assumes prompt refrigeration, which is something…errr…outside of normal Danish customs, say. They are extremely lackadaisical concerning food/sanitation issues. FX- It is entirely normal for a guy to make your burger, prepare the break, slice the veg, take money and give change, all without gloves or ANY handwashing. And most people around me think I am just “uptight” about things and generally chalk it up to me being an American, disregarding science altogether. My point- perhaps in such an environment, foods with these ingredients in them as you described really DO become toxic…unless (segue to my second thought)- If you reheat it REALLY well, for a specified sufficient length of time, wouldn’t that clear up all risk? I’m sure this is only true to a point, but in any case wouldn’t people be served better if they were taught safe reheating practices rather than be told that it becomes “poisonous”? I had an employee of the Kindergarten explain to me VERY confidently how parsley becomes poisonous, as in it lets out toxins- if reheated, same for spinach and cilantro. She seemed singularly unimpressed that I didn’t know these vegetables had these traits. Sorry to be long winded. So reheating thoroughly solves this? or not? ---
**Author:** ![Torpor\_Beast](https://avatars.discourse-cdn.com/v4/letter/t/71e660/32.png) [@Torpor\_Beast](https://boards.straightdope.com/u/Torpor_Beast)\ **Post date:** [April 3, 2004, 8:10pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/9 "2004-04-03T20:10:55Z")
(Standard IANAD disclaimer applies) Actually, spoiled food IS poisonous. The some of the bacteria and other micro-organisms that cause food to spoil produce various not so nice toxins. Some types of food poisoning are caused by the bacteria in food multiplying in your body and other types are caused by the toxins. No amount of heating will destroy some of these toxins. At least if you still plan to eat the food. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [April 3, 2004, 8:14pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/10 "2004-04-03T20:14:15Z")
Not that I believe reheating is a problem, [but](http://www.sassibrix.com/01_23_04.html) > [@](#): > > The other day I was reading an email from a member of a yahoo group that I belong to who lives in Australia. She was > giving us a recipe containing spinach and mentioned that we > should remember not to reheat the leftovers, saying, “Of course, > you all knew that.” No, the majority of us had never heard that > spinach contains nitrates and that reheating it will turn the > nitrates into nitrites, which are carcinogenic. She said that > factory-made frozen spinach is prepared in a special way > and checked for nitrate levels. The story is probably a mutant outgrowth of [nitrite studies done back in the 60’s and 70’s](http://www.inchem.org/documents/ehc/ehc/ehc005.htm): > [@](#): > > a few cases of methaemoglobinaemia in infants have been associated with the consumption of water containing less than 50 mg per litre. Cases of methaemoglobinaemia in babies fed with spinach purée or carrot juice (both of which may contain very high levels of nitrates) have been reported, but there are too few data to establish dose-response relationships. ---
**Author:** ![cabdude](https://avatars.discourse-cdn.com/v4/letter/c/58956e/32.png) [@cabdude](https://boards.straightdope.com/u/cabdude)\ **Post date:** [April 3, 2004, 8:17pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/11 "2004-04-03T20:17:43Z")
What you’re saying is quite correct, but why is parsley being singled out here? The longer food stays at roomish temperature, the greater the build up of harmful bacteria which produce toxins, etc. Heating to a high enough temp kills the bacteria but leaves the toxins. This applies to ALL foods - the OP specifically mentioned a Danish phobia against reheating parsley, spinach, cilantro. Presumably reheating shellfish, hotdogs, poultry is fine, as long as there is no garnish? ---
**Author:** ![Spiny\_Norman](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@Spiny\_Norman](https://boards.straightdope.com/u/Spiny_Norman)\ **Post date:** [April 3, 2004, 9:00pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/12 "2004-04-03T21:00:24Z")
- actually, an old Home Economics’ Teacher’s tale, if such a thing exists. Being a Dane who took Home Economics, I have encountered this idea and did the reasearch, and there is some factual basis, althought it’s been mostly distorted. Parsley carries bacteria from the ground, obviously. If the parsley is cooked with the dish (in _persillesovs_, for instance), there’s no problem. But raw, chopped parsley is (was) sometimes used as garnish on a cooked dish, added just before serving. _If_ this is done, and _if_ the dish is then refrigerated, the bacteria won’t be killed. On the contrary, they’ll multiply and give off toxins. If you then reheat the dish the next day, you will kill off the bacteria, but the toxins do not get destroyed by heating. And then you’ll have a dish that can pose a risk. It’s not at all likely, but for some reason the warning has been hammered home to generation after generation. The spinach idea is somewhat similar: Spinach contains nitrates, and some bacteria convert nitrates to nitrites. Nitrites are dangerous for small children (under 1 year). Again, if you’re not careful, bacteria may increase the nitrite levels in the dish - and reheating can’t do away with the nitrites, just like it can’t do away with the toxins. And that’s where I think the myth is rooted: Neither nitrites from spinach nor toxins from parsley-carried bacteria can be removed by recheating the dish. Most people were told this in 7th grade, but the exact circumstances are lost in the mist of time and only the vague idea that reheating parsley and spinach is somehow bad remains. Have your Danish friends refer to this link, or use it as language training 😃 : [forbrug.dk](http://www.forbrugerstyrelsen.dk/pj/pj320932.htm) So, problem solved: What are you doing in Denmark and where are you ? Enjoy a Paaskebryg for me, willya ? They’re hard to come by in Southern California… ---
**Author:** ![Torpor\_Beast](https://avatars.discourse-cdn.com/v4/letter/t/71e660/32.png) [@Torpor\_Beast](https://boards.straightdope.com/u/Torpor_Beast)\ **Post date:** [April 3, 2004, 9:00pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/13 "2004-04-03T21:00:39Z")
> [@cabdude](#): > > What you’re saying is quite correct, but why is parsley being singled out here? The longer food stays at roomish temperature, the greater the build up of harmful bacteria which produce toxins, etc. Heating to a high enough temp kills the bacteria but leaves the toxins. This applies to ALL foods - the OP specifically mentioned a Danish phobia against reheating parsley, spinach, cilantro. Presumably reheating shellfish, hotdogs, poultry is fine, as long as there is no garnish? I think there’s no reason to single out parsley in this case. Nitrate can be found in all plants. [This](http://muextension.missouri.edu/explore/envqual/wq0258.htm) link suggests that mostly small infants are vulnerable to nitrate poisoning. [Here’s](http://members.tripod.com/~Prof_Anil_Aggrawal/poiso023.html) an interesting interview with a toxicologist about nitrite/nitrate poisoning. > [@](#): > > There are more interesting facts Tarun. Nitrite poisoning from spinach has also occurred. During 1959-65 in Germany there were 15 cases of nitrite poisoning in infants, aged two to ten months, who had eaten spinach. Nitrite and the remains of spinach were found in the stomach contents of one of the infants. Two factors were responsible. First, the excessive use of nitrate fertilizer, which should not, but often did, exceed 80 kg/hectare. Second, bacterial activity converted the nitrate in spinach into nitrite. Samples of spinach, fresh, frozen and tinned, showed a nitrate contamination of from 40 to 2100 mg/kg. The risk arose when the feed was prepared in advance and stored overlong at room temperature. Even after cooking, a sufficient number of bacteria remained to produce nitrite. The maximum nitrate content of spinach should not exceed 200mg/kg. It has even been recommended that during the first three months infants should not be given spinach." ---
**Author:** ![Torpor\_Beast](https://avatars.discourse-cdn.com/v4/letter/t/71e660/32.png) [@Torpor\_Beast](https://boards.straightdope.com/u/Torpor_Beast)\ **Post date:** [April 3, 2004, 9:02pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/14 "2004-04-03T21:02:45Z")
Ah, simulpost with Norman… ☹ ---
**Author:** ![Takeo\_Jr](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@Takeo\_Jr](https://boards.straightdope.com/u/Takeo_Jr)\ **Post date:** [April 3, 2004, 9:47pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/15 "2004-04-03T21:47:44Z")
So, problem solved: What are you doing in Denmark and where are you ? Enjoy a Paaskebryg for me, willya ? They’re hard to come by in Southern California… Im a musician living in Copenhagen. I would if I were a drinker…I rarely drink if ever but have to say Denmark does have some remarkably good beer. It’s strong, but it’s good. Problem ain’t exactly “solved”…but it’s a lot more clear to me what people are on about, but in general, they are way off. Luckily, the consequences of their actions to their PERCEIVED reality are not likely to cause any problems, and may very well prevent some accidents, though not for the reasons thought. I’m new here and I have to say, you guys are FAST- I posted a question, went to get something in the kitchen, sat down, and lo and behold- I had been addressed! Viva la Brave New World!!! THANKS! -TJ ---
**Author:** ![wolfman](https://avatars.discourse-cdn.com/v4/letter/w/a8b319/32.png) [@wolfman](https://boards.straightdope.com/u/wolfman)\ **Post date:** [April 3, 2004, 11:01pm UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/16 "2004-04-03T23:01:53Z")
> [@](#): > > Nitrite poisoning from spinach has also occurred. During 1959-65 in Germany there were 15 cases of nitrite poisoning in infants, aged two to ten months, who had eaten spinach. Nitrite and the remains of spinach were found in the stomach contents of one of the infants. Even though it’s about 15 years yate, I’ll have to send this to my mom to prove that yes, in fact a little spinach _has_ hurt somebody. ---
**Author:** ![PatriotX](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@PatriotX](https://boards.straightdope.com/u/PatriotX)\ **Post date:** [April 4, 2004, 12:59am UTC](https://boards.straightdope.com/t/are-parsley-and-spinach-dangerous-to-reheat/238086/17 "2004-04-04T00:59:17Z")
I’ve worked with food professionally since I was eight years old. I’ve never heard of any warnings _particular_ to or _peculiar_ to or somehow _unique_ to parsley, spinach, cilantro etc. There’re a number of concerns with food _in general_ that apply to these foods. There’re a number dishes in the frozen food aisle that feature spinach that’s been cooked and is to be reheated. This is also true of all canned spinach. The same is true of parsley in canned soups. I think that this is most prob’ly almost entirely pure hokum.