"Peter H.M. Brooks" wrote:

> I'm making a curry for my father's 85th birthday party tomorrow. Not
> that that's particularly relevant to the post, but still...
>
> My sister works for a food retailer and is consequently paranoid about
> various matters related to food - as, of course, any good food retailer
> must be. I'm not sure that quite the same level of paranoia is required
> at home though.
>
> My sister is of the opinion that it would be dangerous to re-heat the
> curry tomorrow morning, then travel over to her house (a twenty minute
> drive) and then heat it again for serving. She's afraid that everybody
> will be poisoned if this happens. According to her re-heating the food
> twice will be much more dangerous than re-heating it twice.
>
> She might be right, but I'm interested to know exactly what the
> mechanism is. If I heat food to boiling point then only bacteria that
> survive at higher temparatures will survive, during the cooling period
> it may indeed be re-colonised, by bacteria from the air but again this
> would be killed by re-heating to boiling (and keeping it there for a few
> minutes, of course).
>
> I can see that it is wise usually to keep food refridgerated and only
> heat that which is required shortly before the meal, and I'm not
> advocating re-heating the same curry many times over several days.
> However, I am interested to know just how big the danger of food
> poisoning would be from two re-headings tomorrow relative to only one.
> Would it truly create a danger of poisoning or is it paranoid to worry
> about it?

You really have to cook it thoroughly to get rid of bacteria. It's that in
between stage, warm, that allows the bacteria to really flourish, bt warming
it up, letting it cool off a bit for transport, and then re-warming that
keeps the food in the prime temperature range for bacteria that she is
concerned about. She may have a point about the amount of time the food
will spend in that prime science project temperature range without heating
it enough to kill bacteria and destroy it's toxins.