I like to eat off silicone containers. I've noticed that if I rinse them right away after eating, there will be basically no visible residue left on the surface.

Now let's say that, err, I had a friend who is lazy and gross and was considering rinsing a container that way and placing it in the fridge in between meals, eating in that same container throughout the day and only washing it properly after dinner.

That would be yucky, yes, but not dangerous, right? Since the fridge can keep a whole container of food safe for a few days, surely it can keep some microscopic food residue safe from morning until night? The food would only stay briefly in the temperature danger zone (4-60 C or 40-140 F) when eating, so it wouldn't add up to two hours of non-safe temp throughout the day.

I coul-I mean, my friend could even rinse with hot water, or place it in the freezer instead to make extra sure. Or you know, actually wash it for real, but it's a really lazy person I'm talking about here.

EDIT - To summarize: I want to know whether it is dangerous to not fully clean the container in between meals throughout a day (like three or four times). I would only give it a quick rinse to remove visible residue, and then keep it under 4 C / 40 F, where bacteria won't grow too quickly (and then clean it properly afterward for the next day).

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    Technically a more accurate tag would be 'not cleaning', but I suppose this will do. Commented Apr 5, 2021 at 20:40
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    Are you really talking about the difference between adding soap vs not? Is your question better posed as: Is soap necessary to sanitize by silicone container?
    – moscafj
    Commented Apr 5, 2021 at 20:54
  • Not quite, the question is more like about whether it is dangerous to not fully clean the container in between meals throughout a day (like three or four times), if I keep it under 4 C / 40 F, where bacteria won't grow too quickly (and then clean it properly afterward for the next day). I'll add this to the end of the question to hopefully make it more clear. Commented Apr 5, 2021 at 21:06
  • Yeah...but you are suggesting everything short of adding soap or sanitizer...no? ...rinsing....cold...hot...refrigerating...freezing...
    – moscafj
    Commented Apr 5, 2021 at 21:08
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    I don't think this can be answered without knowing what and how you eat out of the container. E.g. for eating "dry" bread from a wooden plate (or silicone container), I'd consider shaking out the crumbs quite sufficient. If OTOH, you're talking of eating fish and a greasy sauce...
    – cbeleites
    Commented Apr 6, 2021 at 17:45

4 Answers 4


I see you're familiar with the "danger zone" concept. I think the only on-topic way to answer this is to help you add up the "danger zone" time, (and raise the concern of cross contamination!). I will say in response to your heading, there is no "loophole" in food safety guidelines. They are pretty stark in that things are either safe or not.

Eating something that has been treated "unsafe" aren't guaranteed to make you ill--but for this site, "will it make me sick?" is off-topic, while "is this considered food safe?" is on-topic, so I'll focus solely on the latter.

Cross contamination ❌

It's not guaranteed this will happen, but every time you handle something, you risk cross contamination. Uncovered food in the fridge can also be a contamination vector. Each time you reuse a dish without washing, you essentially double your chances of having a problem. A trace of e. coli on an apple peel during breakfast has a chance to be transfer to the plate, grow all day long and be ingested during every meal of the day, increasing the chances that you might get ill.

Danger zone math ⚡

Keep in mind that this is a CUMULATIVE time for the food (and residue)--it doesn't reset when the food hits your bowl. Also, food safety guidelines consider a plate to be "contaminated" with food from the time food hits it until the plate is properly washed/sanitized (ie, with soap). Even if there is no visible residue, if it hasn't been washed properly the plate is treated the same as if there was still a full serving of food on it, from a food safety perspective.

Based on all of that, you'd need to add up time the ingredients (for everything that was on the plate) are unrefrigerated coming home from the grocery, being prepared & cooked (between cold and hot), after cooking on your plate, time in the fridge while cooling back down, repeat for each meal.

If you use the same plate for breakfast, lunch, dinner, and dessert without washing, you'd essentially be calculating the danger zone time as if you had breakfast leftovers that you refrigerated then reheated at lunch. Then added extra lunch leftovers and put them in the fridge. Then you reheated breakfast and lunch leftovers, added some dinner leftovers and back into the fridge. Then reheated breakfast, lunch, and dinner leftovers to eat them for dessert.

So it gets complicated to do all that math... But there's a lot of time that will accumulate as it passes from warm to cold to warm to cold, etc.

My verdict? 👨‍⚖️

It seems unlikely that you'd be able to add up all that time in the danger zone and still stay within the time window that is considered food safe by government food safety guidelines.

If you're already going to rinse it water to remove visible residue, a quick swipe of a soapy wash cloth seems like a low-difficulty added effort to wash away the remaining unseen food & bacterial residue. I'd even possibly argue that a quick soapy wash is no more difficult than trying to find a way to stay within food safety guidelines.

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    I see! I am just now learning about food safety and started thinking about this possibility. I did not really consider cross-contamination, yeah. I understand the analogy of refrigerating/reheating leftovers all day, but I'm curious: does the fact that the amount of 'leftovers' in the container is literally not visible to the naked eye not make a difference at all in this regard? Or does it make it a little safer, but not enough that it would be recommended I bet on it? Commented Apr 5, 2021 at 21:41
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    Just to clarify, if I were 100% sure none of the, erhm, non-roomtemp-safe ingredients hadn't spent 2h total in the danger zone, would this practice be considered technically food-safe? I know it's a bit gross and not something anyone would recommend, but it would be as safe as any other combination of danger-zone temps under 2 hours, right? Commented Apr 5, 2021 at 21:41
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    By the way, thanks a lot for your detailed response! I will mark it as accepted. I still have a few doubts, but I suppose your final verdict implies it would be safe as long as I got my danger zone maths correct, though it would be hard to make sure and thus not really recommended. That makes perfect sense and has satisfied my curiosity! Commented Apr 5, 2021 at 22:04
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    Pathogens (bacteria, etc) are the real enemy. You can't usually see bacteria because they are so tiny. Their tiny size means they only need a tiny amount of "stuff" to feed on and multiply. In fact--let's forget about food residue entirely. Bacteria like e coli (found in both meat and vegetables) can live on surfaces for up to a full day. Even without food residue, e coli can transfer from a leaf of lettuce to the plate, then live on the plate until the next meal, where it could contaminate that food
    – AMtwo
    Commented Apr 6, 2021 at 0:59
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    Could you edit your answer's verdict to remove the triple negative? Makes it quite confusing to read. 'Unlikely ... not ... NOT safe'.
    – orlp
    Commented Apr 6, 2021 at 7:24

As you are asking about a single day, I'm pretty sure it's safe.

Lets compare the concept with how we handle our typical leftovers;

Say we made chilly, and stored it in a container in our fridge, so every time we decide make tacos, simply could scoop out some chilly. 2 days after we made the chilly, it came down to the last scoop. Would we hesitate to scrape the bits of residue from the edges of the contain? I wouldn't.

Of course, this is assuming that nothing dirty made contact with the container while you were using it.

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    Yeah, that is basically my reasoning! Since the leftovers are basically microscopic it sounds to me like what I'm describing would be even a bit safer than your chilly scenario, technically. The only difference is that you'd have eaten in the container and taken it out briefly a few times (maybe eat quickly?), but I don't suppose tiny particles of spit potentially left on it would make THAT big of a difference over one day Commented Apr 5, 2021 at 21:46
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    Well, if the proposed mode of eating includes putting tools back from the mouth into the container that would be a substantial difference compared to using a fresh spoon every time you scoop out of the chilly.
    – cbeleites
    Commented Apr 6, 2021 at 17:43

I don't think that this plan is necessarily unsafe, in terms of likelihood of sickening or killing you, but it's definitely less safe than washing the container.

It only requires a microscopic amount of pathogens to make you extremely sick; that there is no visible residue is not as strong an argument as you seem to think. Rinsing is better with soap, too. for most consumer-grade soaps it's surfactant action that gets rid of pathogens-- they're not as good at clinging to surfaces when there is soap in the mix.

We're also talking about probabilities that add up over time-- you will be rolling the dice every meal, every day, with worse odds of success without washing. Your absolute risk of becoming ill as a result of doing this might not be very high, but your relative risk (compared to washing your dishes, or using clean ones) will be higher.

To illustrate, let's consider:

There are about 265,000 illnesses from E. coli in the United States each year. If the US population is 328,000,000, and the incidence of E. coli infections is evenly distributed among the population (it isn't, but let's keep things simpler), that is an annual illness rate per person of ~0.0008, or 0.08%. We'll also pretend that E. coli is the only foodborne illness risk there is.

That's around one illness per 1,250 people per year, which isn't too bad. Let's imagine that your plan doubles the relative risk (that's a huge jump and I have no data about how this practice might affect your risk, but should still illustrate the ideas). That would mean a 0.16% illness rate among people that eat that way.

That's still pretty low, in absolute terms! Most people certainly do riskier things every day. And yet it would still be enough to cause an extra 265,000 E. coli illnesses per year (if everyone made the switch), for a total of 530,000. That's a lot of extra illness.

But the point is that, while the absolute risk is still pretty low (0.16%), the relative risk is twice as severe, and the excess risk is (in this toy example) 100% avoidable with little effort.

Saying that it's safe is a pretty fuzzily defined conclusion-- your risk is never going to be zero, and is zero risk even the standard to use? Saying that it's safe enough for your risk tolerance and cleaning preferences is more defined but subjective; no one else can tell you if it's safe enough for your preferences. It is all but guaranteed to be less safe than washing the container.

  • I think you are an order of magnitude off -- 250k/250m = 1/1000. Still unlikely but not as remote. Commented Apr 7, 2021 at 23:03
  • Yes, it's a result in ten-thousandths; it's about 8 ten-thousandths, or 8 in 10,000, which is just a bit under one illness per 1,000 ; it is not "under one illness per 10,000 people per year" but 8 times that. Commented Apr 8, 2021 at 21:27
  • @Peter-ReinstateMonica Ah, that would do it! Thanks for spotting the error and pointing me to the right place.
    – Upper_Case
    Commented Apr 8, 2021 at 21:29

I'd add that it depends a lot on the food. On one end you have food that's inherently on the safe side, like sour milk products: They can safely stay at room temperature for a day or longer — being kept warm is how they are actually produced. The more acidic, sweet or salty a dish is, the safer.

On the unsafe end would be proteins like raw egg (in mayo) or raw, minced meat or fish which are bacteria breeding grounds.

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