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Is it safe to eat greens that were in a hot car?
March 24, 2012 7:13 PM   Subscribe

Should I Eat This? filter: Farmer's market lettuce left in a hot car for (up to) a few hours - is it safe to eat?

I hit up the farmer's market Saturday morning for some lovely fresh greens - spinach, swiss chard, romaine, etc. The day was cool, overcast and rainy (and forecasted to stay that way) so I figured the greens would be fine in the car while we went to the movies. Unfortunately when the movie let out we found skies had cleared and the sun had come out. The greens, sitting on the back seat of the car, were in direct sunlight and quite warm. They couldn't have been in the sun for more than 2-3 hours, possibly a lot less.

I immediately put the greens in the cooler, and then in the fridge when we returned home. I'd hate to throw them out but... are they safe to eat?
posted by geeky to Food & Drink (23 answers total)
 
If the lettuce is bad, you will be able to tell. It will be slimy and not look appetizing.
posted by doomtop at 7:19 PM on March 24, 2012 [1 favorite]


think about it, veggies grow in hot temps all summer, they don't spoil like meat/dairy. I'm sure they are a bit wilted, but should be safe.
posted by HuronBob at 7:19 PM on March 24, 2012 [11 favorites]


Yes. Eat them.
posted by vegartanipla at 7:19 PM on March 24, 2012


Yes.
posted by Balonious Assault at 7:19 PM on March 24, 2012


The greens are fine, they were growing outside in the dirt under the sun just a few days ago.
posted by jamaro at 7:19 PM on March 24, 2012


What could possibly be wrong with them? They grow in the sun. They might have gotten a little wilty but nothing that's going to hurt you as long as you wash them, which you should do no matter what.
posted by LionIndex at 7:21 PM on March 24, 2012


They're fine. If they're wilted, soak them in cold water for maybe half an hour.
posted by DoubleLune at 7:21 PM on March 24, 2012


Thanks MeFites! They're not really even wilted. I figured they were fine to eat, but wanted to ask just in case there was something I was overlooking. :)
posted by geeky at 7:31 PM on March 24, 2012


I do think they'd be fine to eat, but the "they grow in the sun" argument doesn't work, because when they are growing, they are rooted in the soil and can draw water from it. After they've been harvested they can more easily dry out. But I think the worst they will be is a bit dry, not actually dangerous to eat. You can perk them up by placing the stems in icewater for a while.
posted by parrot_person at 7:53 PM on March 24, 2012 [2 favorites]


think about it, veggies grow in hot temps all summer, they don't spoil like meat/dairy.
What could possibly be wrong with them? They grow in the sun.


This is not a good way to think about food safety.

It's not so much that you should be concerned about potential damage (like wilting) to the veggie in question by the sun, but about what happens to all the microorganisms (some good, some not-so-good) that may be living on a moist veggie and get stuck in warm-hot place. Those conditions (warmth and moisture) are ideal for many kinds microbial growth.

Fresh produce can be exposed to pathogenic bacteria through many, many, many sources such as soil, water, and human hands. There are really nasty bacteria that like to hang out in the soil, water, or under fingernails and don’t have a difficult time moving from the ground water to an entirely different ecosystem, like say - your gut.

So say you lettuce has a couple hundred of some harmful bacteria hanging out on it. Not enough to make you sick. Leave the lettuce and bacteria in an environment that potentiates growth (like the back of your hot car), and you go from a couple hundred nasty bacteria to a few hundred thousand (which might make you not feel so great) pretty quickly.

If the lettuce is bad, you will be able to tell. It will be slimy and not look appetizing.

While slimy lettuce probably means the lettuce isn't a good idea to eat, regular feeling/looking lettuce can be just as problematic because you can’t actually see, smell, or taste the harmful bacteria that are responsible for most food-borne illness.

Your lettuce is probably fine*, and I know I am a little bit of an alarmist, but it’s this kind of thinking that leads people to make poor food safety choices which can effect not only themselves but the people the serve food to.

Here is an excellent way to think about food safety and foodborne illness.

*I would probably eat it. I eat a lot of stuff I think/know I shouldn't. Sometimes I pay for it dearly. I am pretty crazy hygenic about the food I feed other people though.
posted by OsoMeaty at 8:29 PM on March 24, 2012 [7 favorites]


Also the argument that: think about it, veggies grow in hot temps all summer, is also ill informed because while they are growing (in the sun) their immune systems are active and they are able to ward off or keep microbrial growth to a minimum. So a plant in the ground is different story than the plant in your fridge.
posted by OsoMeaty at 8:35 PM on March 24, 2012 [2 favorites]


Well, first, plant diseases are highly unlikely to have any sort of negative effect on mammals, so the presence of plant anti-microbial immune systems isn't really an issue. Second, note that every bacteria listed in the food safety website you link to is transmitted through meat, poutry, or dairy, or through produce that has been in contact with those items and been insufficiently cleaned. Staph Aurea for example isn't going to produce toxins on a piece of lettuce because it really has no food source there, no matter what the heat and moisture conditions are.
posted by LionIndex at 9:10 PM on March 24, 2012


So yeah, microbes could reproduce under those conditions, but that's why you wash produce.
posted by LionIndex at 9:12 PM on March 24, 2012 [1 favorite]


They're fine. You should take them home, rinse them all in cool fresh water, maybe trim their stem-ends a little and place them upright in a mug of water in the fridge. Alternatively, wash them in water, letting them soak a bit, then dry them in a salad spinner and place in a plastic bag in the fridge with a paper towel. They'll perk right up. And for your tougher greens - chard, kale, arugula - if they don't perk to your satisfaction, you can still cook with them.
posted by Miko at 9:13 PM on March 24, 2012


And to be a total pedant, you should always wash ALL fresh produce, especially leafy produce, this way. It's not different advice because it's wilted - this is how to treat produce.
posted by Miko at 9:15 PM on March 24, 2012


The salient microbial health hazards associated with fresh produce are enterics of fecal origin, for the most part the poop gets on to produce from runoff from nearby animal agriculture. Regarless, they arn't going to grow in your hot dry car on the hostile surface of a healthy lettuce.

However, even if incubation in your car is unlikely to exacerbate microbial issues, you don't know if there is poop on your lettuce or not so it is still a good idea to wash it.

LionIndex, Staph aureus is associated with skin, utters, and nasal cavities, one wouldn't expect to find it on lettuce. The things to worry about are coliforms like E. coli, Salmonella, and Klebsiella or other agricultural fecal zoonotics like Campylobacter.
posted by Blasdelb at 9:44 PM on March 24, 2012 [2 favorites]


And to be a total pedant, you should always wash ALL fresh produce, especially leafy produce, this way. It's not different advice because it's wilted - this is how to treat produce.

Yes, organic as well as conventional. It doesn't matter how it was grown if someone dropped gasoline or poop on it just before it was harvested!
posted by threeants at 9:49 PM on March 24, 2012


The lettuce's immune system is also largely irrelevant to the microbial safety of your meal as the things that make lettuce sick, assuming you are not catastrophically immunocompromised, will not make you sick. The only microbial factors of genuine concern come from poop, that poop will remain infectious in the field for a long time, and while it won't be aided by incubation in your car, it won't be hurt either.

There are also non-microbial good reasons to wash produce related to the sketchy journey that produce took to the store or farmers market, chemicals applied to the produce, and in the case of lettuce mildly carcinogenic insecticides secreted by most varieties.
posted by Blasdelb at 9:55 PM on March 24, 2012 [2 favorites]



The lettuce's immune system is also largely irrelevant to the microbial safety of your meal as the things that make lettuce sick, assuming you are not catastrophically immunocompromised, will not make you sick.

Yes, and I didn't mean to imply that plant pathogens = human pathogens, although I can understand that from the wording of my answer that isn’t particularly clear.

However, I was under the impression that unhealthy or damaged leaves (especially those with soft-rot) are thought to enhance the growth and survival rate of E.coli and Salmonella on lettuce and spinach.

So in a very circuitous matter I would argue that the lack of functional immunity could influence the likelihood of bacterial proliferation on lettuce.

posted by OsoMeaty at 10:36 PM on March 24, 2012


LionIndex, Staph aureus is associated with skin, utters, and nasal cavities, one wouldn't expect to find it on lettuce. The things to worry about are coliforms like E. coli, Salmonella, and Klebsiella or other agricultural fecal zoonotics like Campylobacter.

Yeah, I just used that as an example from the list OsoMeaty linked to since I have some familiarity with it. There have been obvious issues with E. coli in produce.


Also, if just non-refrigeration of the produce is a problem in and of itself, farmer's markets would have some serious issues - it seems like the produce generally gets to the markets in unrefrigerated vans, and is then sitting out in the open for however long the market goes.
posted by LionIndex at 10:58 PM on March 24, 2012


I knew I could count on you MeFites to beanplate my lettuce! :)

Thank you, OsoMeaty and Blasdelb. You guys addressed my main concern - that any contamination on the greens (e-coli or similar) would flourish in the hot car. I know the first rule of food safety is to store food at proper temperatures to discourage bacterial growth.

I really don't want to throw the greens out, I'm healthy, and it sounds like the risk is minimal, so I'll just wash the greens thoroughly and eat as planned. I was planning to cook the chard anyway.
posted by geeky at 5:23 AM on March 25, 2012


This is the kind of microbial thing that could hurt you, An outbreak of Escherichia coli O157: H7 infections associated with leaf lettuce consumption (PDF).

The primary problem is cell attachment to the leaves. The cells we're worried about won't really meaningfully grow there; even wilted lettuce has precious little in the way of available sugars. The problem is that the fecal contaminants don't need to grow, they just need to remain viable and remain on the lettuce in an infectious concentration, which in some of these bugs can get under 100 cells. Damaged lettuce is still problematic though as it allows for greater penetration of cells, thus protecting them from both cleaning and killing.

Even then though, with lettuce specifically, if there was enough poop going into the field, you're boned regardless of how well you wash, as high enough concentrations can lead to E. coli invading the root systems and traveling up into the edible portions on the inside. (Transmission of Escherichia coli O157:H7 from Contaminated Manure and Irrigation Water to Lettuce Plant Tissue and Its Subsequent Internalization)
posted by Blasdelb at 7:42 AM on March 25, 2012 [2 favorites]


Good news: I've eaten some of the greens and I'm still alive to tell the Internet about it.
posted by geeky at 6:42 PM on March 26, 2012 [1 favorite]


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