Food myths, food facts, food questions...
Food myths, food facts, food questions...
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Mobsta

Original Poster:

5,614 posts

283 months

Tuesday 6th November 2012
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I did a one day food health and hygiene course many years ago, and seem to remember learning that, at the rate bacteria doubles, at least 8 hours was needed if food left sitting on the counter was to be dangerous. Let's assume normal UK temperatures.

My grandmother would leave food out a lot longer, overnight semi regularly. No sickness, no problems.

My first question: why can food not be frozen twice? GF insists it will go off, if frozen twice. I say it won't, so long as its not out for more than 8 hours. It's temperature will be below room temperature and colder than a fridge, whilst defrosting, so it won't even start going off until up to room temp.

Also, reheating food - surely the same 8 hour rule applies. Ie, food which lasts 3 days in the fridge will only "go off" during the moments or hours during which its temperature is above that of a fridge. If I cool something, bang it straight in the fridge, I should be able to reheat it, eat half, then bang it straight back in the fridge, should I not?

GF refuses point blank to heat up any takeaway, after its been refrigerated. Why rice is a no no as well, I do not know. It's always freshly cooked and contains no lingering bacteria of its own.

And finally, sell by dates. I ignore them with one exception, fresh meat. How fussy is your household when it comes to sell by dates?

Pothole

34,367 posts

310 months

Tuesday 6th November 2012
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NHS.UK said:
Uncooked rice can contain spores of Bacillus cereus, a bacterium that can cause food poisoning. When the rice is cooked, the spores can survive.
If the rice is left standing at room temperature, the spores can grow into bacteria. These bacteria will multiply and may produce toxins (poisons) that cause vomiting or diarrhoea.
The longer cooked rice is left at room temperature, the more likely it is that the bacteria or toxins could make the rice unsafe to eat.
Tips on serving rice safely

Ideally, serve rice as soon as it has been cooked.
If that isn't possible, cool the rice as quickly as possible (ideally within one hour).
Keep rice in the fridge for no more than one day until reheating.
When you reheat any rice, always check that the dish is steaming hot all the way through.
Do not reheat rice more than once.
ETA, takeaway rice has most likely already been reheated, especially fried rice, which is often boiled first.

I threw out some Hollandaise sauce from my Mum's fridge this morning. Its use by date was July.

KungFuPanda

4,637 posts

198 months

Wednesday 7th November 2012
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I eat rice which has been kept at room temperature for two, sometime three days with no ill effects. Coming from an oriental family, I've been doing this since a child.

I remember watching Saturday Morning Kitchen once when someone called in and asked whether it would be safe to eat reheated rice and Ken Hom who was a guest chef that day said it was absolutely safe however James Martin butted in and said it was fairly risky. Seriously, trust the guys that have been eating rice for centuries...

21TonyK

13,245 posts

237 months

Wednesday 7th November 2012
quotequote all
KungFuPanda said:
I eat rice which has been kept at room temperature for two, sometime three days with no ill effects. Coming from an oriental family, I've been doing this since a child.

I remember watching Saturday Morning Kitchen once when someone called in and asked whether it would be safe to eat reheated rice and Ken Hom who was a guest chef that day said it was absolutely safe however James Martin butted in and said it was fairly risky. Seriously, trust the guys that have been eating rice for centuries...
Considering the severity of the potential poisoning from rice I will only reheat rice that I have chilled from hot and kept in a fridge. I would not reheat plain takeaway rice as it's easy to cook fresh but I'll take the risk for a decent mixed fried rice!

It's one of those things, I will eat a raw egg, raw meat (steak) and fish, unpasturised soft cheeses etc which many would run a mile from. It's what you are used to, understand and are comfortable with.

My concern with questions like this is if the OP doesn't already know the answer they many not fully understand the reasoning behind it so given advice that contradicts what is known to be categorically safe is potentially dangerous.

The "best" answer is to read the Food Standards Agency guidance.

Mobsta

Original Poster:

5,614 posts

283 months

Wednesday 7th November 2012
quotequote all
21TonyK said:
My concern with questions like this is if the OP doesn't already know the answer they many not fully understand the reasoning behind it so given advice that contradicts what is known to be categorically safe is potentially dangerous.
My concern is the voice in my ear, AKA girlfriend, who insists we can and cant do certain things.

Must admit, Im very surprised by the "days at room temp" from kung fu panda, even Im not that brave.

I'll happily eat spices which are years out of date (I tend not to read the label), but get the stick if I get caught using them on our food...

21TonyK

13,245 posts

237 months

Wednesday 7th November 2012
quotequote all
Mobsta said:
y concern is the voice in my ear, AKA girlfriend, who insists we can and cant do certain things.

Must admit, Im very surprised by the "days at room temp" from kung fu panda, even Im not that brave.

I'll happily eat spices which are years out of date (I tend not to read the label), but get the stick if I get caught using them on our food...
With regard to double freezing / reheating etc it's not so much a specific time at a certain temp it's baterial growth rates, residual contamination from previous growth etc etc Refridgeration and freezing only slow bacterial growth, they don't stop it or reverse it.

So, for example, lets say bacteria doubles every hour above 10 degrees (it's not the case but for examples sake). And lets say more that 1000 bacteria are harmful to you, it's closer to millions but lets say 1000.

You buy a bit of chicken and bring it home with 10 bacteria on it. If you cook it and eat it straight away you kill 9 of the bacteria and eat 1. No issue.

Same chicken gets cooked and some of it eaten then left out to cool for 4 hours before going into the fridge. During those 3 hours 1 bacteria becomes 2, becomes 4, becomes 8, becomes 16.

It then sits in the fridge for 3 days where bacteria doubles every 15 hours (again just an example where it slows down). 16 becomes 32, then 64, then 128, then 256 and nearly 512.

If you reheat this thoroughly in a curry or something you kill most of this bacteria and everyone is happy. If you take it out and leave it on the side for a couple of hours and have it in a salad then that 512 may double again making it potentially dangerous.

(TO ALL: I know I'd be fine eating properly cooked and stored chicken from a fridge after 3 days but this is an example to highlight some of the issues!)

The best thing to do is download the "Safer Food Better Business" pack from the FSA website, that gives lots of practical guidance.

As for defrost, freeze / refreeze etc similar issues can arise but most of the time it is more to do with the damage to the product in the refreezing process. Domestic freezers slow freeze food during which time large ice crystals form with puncture the cell walls causing food to lose structure and hence moisture. Meats will loose texture and become pulpy and vegetables turn to mush. This is why most frozen products containing meat are low grade process meats.

SpeedMattersNot

4,506 posts

224 months

Wednesday 7th November 2012
quotequote all
I leave my takeaways out over night and not yet had an issue, but to be fair I do eat them cold. Mostly as punishment for ordering far too much when drunk.

I think the smell test rules above all else. You know when you smell something if it's a bit dodgy...and if you can't tell even after you've had the first bite, you probably deserve to be punished through food poisoning.

I know someone who claimed to have eaten raw chicken. Zero sympathy.

Mobsta

Original Poster:

5,614 posts

283 months

Wednesday 7th November 2012
quotequote all
21TonyK said:
Mobsta said:
y concern is the voice in my ear, AKA girlfriend, who insists we can and cant do certain things.

Must admit, Im very surprised by the "days at room temp" from kung fu panda, even Im not that brave.

I'll happily eat spices which are years out of date (I tend not to read the label), but get the stick if I get caught using them on our food...
With regard to double freezing / reheating etc it's not so much a specific time at a certain temp it's baterial growth rates, residual contamination from previous growth etc etc Refridgeration and freezing only slow bacterial growth, they don't stop it or reverse it.

So, for example, lets say bacteria doubles every hour above 10 degrees (it's not the case but for examples sake). And lets say more that 1000 bacteria are harmful to you, it's closer to millions but lets say 1000.

You buy a bit of chicken and bring it home with 10 bacteria on it. If you cook it and eat it straight away you kill 9 of the bacteria and eat 1. No issue.

Same chicken gets cooked and some of it eaten then left out to cool for 4 hours before going into the fridge. During those 3 hours 1 bacteria becomes 2, becomes 4, becomes 8, becomes 16.

It then sits in the fridge for 3 days where bacteria doubles every 15 hours (again just an example where it slows down). 16 becomes 32, then 64, then 128, then 256 and nearly 512.

If you reheat this thoroughly in a curry or something you kill most of this bacteria and everyone is happy. If you take it out and leave it on the side for a couple of hours and have it in a salad then that 512 may double again making it potentially dangerous.

(TO ALL: I know I'd be fine eating properly cooked and stored chicken from a fridge after 3 days but this is an example to highlight some of the issues!)

The best thing to do is download the "Safer Food Better Business" pack from the FSA website, that gives lots of practical guidance.

As for defrost, freeze / refreeze etc similar issues can arise but most of the time it is more to do with the damage to the product in the refreezing process. Domestic freezers slow freeze food during which time large ice crystals form with puncture the cell walls causing food to lose structure and hence moisture. Meats will loose texture and become pulpy and vegetables turn to mush. This is why most frozen products containing meat are low grade process meats.
This is precisely my thinking yes Nail on the head. But the GF, having been poisoned by her family growing up on numerous occasions, now cannot think logically and refutes any reassurances food is fine.

I dont always let food cool down before refrigerating, it goes straight in the fridge/freezer after half an hour. A single dish isnt enough to defrost or warm up anything in the fridge or freezer to allow that product to start doing the bacteria doubling, another myth logic tells me, food does not have to be cold before it can be frozen.

21TonyK

13,245 posts

237 months

Wednesday 7th November 2012
quotequote all
Mobsta said:
his is precisely my thinking yes Nail on the head. But the GF, having been poisoned by her family growing up on numerous occasions, now cannot think logically and refutes any reassurances food is fine.

I dont always let food cool down before refrigerating, it goes straight in the fridge/freezer after half an hour. A single dish isnt enough to defrost or warm up anything in the fridge or freezer to allow that product to start doing the bacteria doubling, another myth logic tells me, food does not have to be cold before it can be frozen.
Ding. Might not be the best idea to bung a 10Kg roast in the freezer if it's at 75c but a plate of warm food in a fridge or freezer won't hurt. If you are not raising the temp of the fridge or freezer above the ideal temp, <5 or <18 then no issue.

I have to admit to being freakishly anal about this. I have two fridges and three freezers at home. One fridge for dairy, salad and cooked produce <5, one for raw meats and fish <3. Freezers, one for frozen storage and one for freezing stuff <-16, plus my new magic medical freezer that goes to <-80 (but costs a fortune to run!)

miniman

29,958 posts

290 months

Wednesday 7th November 2012
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21TonyK said:
plus my new magic medical freezer that goes to <-80 (but costs a fortune to run!)
Corpses, right?

21TonyK

13,245 posts

237 months

Wednesday 7th November 2012
quotequote all
miniman said:
Corpses, right?
Not that big, although it's and idea. Experimenting with frozen, dehydrated deserts(?) Don't ask me, HC just bleated on about wanting a new toy and I gave in as usual.

missdiane

13,994 posts

277 months

Wednesday 7th November 2012
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I would reheat rice and eat as long as it was over 70, professionally I wouldn't though, rice is one of the worst but apparently the way we have been taught to cook it means we are minimising risk, but don't quote me on that it's what an EHO lady told me once
I think high risk food should not be unrefrigerated for more than 4 hours and if it was hot food, get it in the fridge within 90 mins
Double freezing, I'd only freeze the product if it had changed state; i.e. frozen raw, defrost and cook it then ok to freeze again

Egg rules make me laugh, caterers have strict rules that we have to keep them refrigerated at the bottom of the fridge with the raw meat... where are they in the supermarket? At home we keep chickens and the eggs sit here for up to a month on the side with no issues
Sometimes the guidelines are just silly (or for silly people...)

missdiane

13,994 posts

277 months

Wednesday 7th November 2012
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With regards to dates, I am very fussy frown won't even eat stuff that is on it's last date just in case it hasn't lasted and I get a funny tasting mouthful
Same as bread, once it's out of date I cannot eat it in case I get mould in my mouth
Herbs and spices I won't chuck out though, I'd be silly

Milk is totally different; will drink it in tea til it curdles, sometimes a week out of date
Still can't eat cheese, yoghurt, cream etc. out of date though

21TonyK

13,245 posts

237 months

Wednesday 7th November 2012
quotequote all
missdiane said:
Egg rules make me laugh, caterers have strict rules that we have to keep them refrigerated at the bottom of the fridge with the raw meat... where are they in the supermarket? At home we keep chickens and the eggs sit here for up to a month on the side with no issues
Sometimes the guidelines are just silly (or for silly people...)
At work we have two storage fridges, two storage freezers, a blaster chiller and <-80 freezer. We also have an immediate freezer and two service fridges with stock changes <24 hours.

We then get grief for keeping eggs at ambient, bearing in mind eggs are delivered every other day from a local free range farm!! We rarely have an egg +36 hours old on the premises but thats not in line with regs. rolleyes

Thankfully we have an EHP who has some common sense!

missdiane

13,994 posts

277 months

Wednesday 7th November 2012
quotequote all
Cripes, that must be some big operation or just a nice kitchen hehe

Pferdestarke

7,192 posts

215 months

Wednesday 7th November 2012
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A driend's mother takes the cool box to the supermarket. They live 2 miles away.

I'm more conscious of crossover with raw and cooked, chopping boards and dish cloths. The number of times I've watched friends wipe a chopping board with a dirty dish cloth that they've been using for months is untrue.

missdiane

13,994 posts

277 months

Wednesday 7th November 2012
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Eeww I'm the opposite think I change cloths twice a day and that's just at home hehe

Pferdestarke

7,192 posts

215 months

Wednesday 7th November 2012
quotequote all
missdiane said:
Eeww I'm the opposite think I change cloths twice a day and that's just at home hehe
Well rinsed, weekly is enough at our gaff.

calibrax

4,788 posts

239 months

Wednesday 7th November 2012
quotequote all
KungFuPanda said:
I eat rice which has been kept at room temperature for two, sometime three days with no ill effects. Coming from an oriental family, I've been doing this since a child.

I remember watching Saturday Morning Kitchen once when someone called in and asked whether it would be safe to eat reheated rice and Ken Hom who was a guest chef that day said it was absolutely safe however James Martin butted in and said it was fairly risky. Seriously, trust the guys that have been eating rice for centuries...
The key here are the phrases highlighted in bold. If you've been doing it since you were a child you most likely have antibodies that will kill off the most common bacteria/toxins associated with reheated rice. For those of us who haven't built up those antibodies over many years it could be a nasty shock to the system. Food poisoning from rice is usually pretty bad, and once you've had it once you certainly don't want to experience it ever again!

Mobsta

Original Poster:

5,614 posts

283 months

Thursday 8th November 2012
quotequote all
calibrax said:
Food poisoning from rice is usually pretty bad, and once you've had it once you certainly don't want to experience it ever again!
Myth.

I spoke to a lady who assured me food poisoning was more painful and a worse experience than giving birth.

I (correct me if I'm wrong) now understand it to be the case that food poisoning isn't a light switch. It isn't on or off. You don't either have it (and are practically dying) or not. There are actually a dozen levels of food poisoning, ranging from the finger licking squits for 4 hours, to 24 hours of mild to moderate cramps and the squits, to fully blown hospitalisation, drips and a NDE, and as many levels again inbetween.

Sell by dates is something we've been debating several times a week recently. My argument is this: no retailer wants any risk. Therefore, correctly chilled, the day after the "use by" date is within date. It's the manufacturer or retailers safety net.

But you calculate the date on a percentage.

Raw chicken has 3 days in the fridge. 20% of 3 days is less than 1 day, and I would not give it an extra day under any circumstances.

Processed microwave Rustlers cheap chicken burgers have a shelf life from factory to tummy of over 2 weeks. If something has 2 weeks, I'll happily eat it 4 days over the safety net.

If a food item has a shelf life of 10 months, I'll happily eat it 2 months over the shelf life date.

But will the other half understand this? hehe - she's getting there to be fair, but won't join me. Which is where the kids come in handy so as not to waste food she won't eat wink

Still not clear on this re heated rice thing, though. It's akin to asking her to spend five mins licking a raw chicken drumstick lolly which has been out in the sun for 5 days.