Lets say for example you have some spaghetti dehydrated. Its got tomato sauce, hamburger, onions, garlic etc... in it (minus the noodles). How safe is it to start the re-hydration process for pre-cooked meals in cold water hours before you plan to eat them?

Using the spaghetti example again, say you want to eat at 6pm but you don't want to do the whole warm the water, wait in coozies thing. Can you start the process in cold water at say, 3pm and then just heat up when its time to eat?

This might be a silly question but I just don't know.

I hope its OK since I put them in GSI fair share mug at noon for dinner.

quote billconner: "I hope its OK since I put them in GSI fair share mug at noon for dinner."

I figured it was a silly question but I wanted to be sure. Thanks for the response.

I often add water to my dinner meal at noon and let the plastic bag sit out in the sun all afternoon.

... it has not killed me yet.

I wouldn't do anything with meat in it for more than 1 hour before use. You are IMHO asking for a problem with food poisoning depending on the temperature outside. Look at it this way how long would you let this stuff sit around at home out in the open before you start worrying about food contamination. I really don't think you would want to ruin a great trip by having to cut it short with a bout of diarrhea or vomiting. I know others will say they have left stuff out for quite a while with no problems but maybe they have just been lucky.

Ripple had a very good responce to this very question on a previous thread. I start the rehydration in a nalgene bottle at noon and finish the process by adding more water at dinner and bringing to a boil.

O.K.... Here, I am an expert. I taught my first food safety class about 20 years ago, so pay attention...

NO, IT IS NOT SAFE!

And

IT IS NOT NECESSARY!

First, safety. Food safety rules the "I've done X for years and never got sick" does not apply here. (This gets gross now, so more sensitive people skip ahead to the next paragraph.) If, for example, one got sick every time a food worker din NOT wash their hands, we would never be well. Even if we got sick every time a food service worker with fecal contamination failed to wash their hands... There would be tens of thousands of sick people every day. Washing hands is just one of many many many safe food handling rules. So, just because you didn't get sick over many years doing the wrong thing, just means you were fortunate.

The tough thing about food poisoning is this... People are rarely correct about the source of the illness. What we refer to as 'food poisoning' is really 'food borne illness'. In exceedingly rare cases food borne illnesses show up in a day. Usually it is several days to a couple weeks before the illness is apparent from the time of the infection. The good news is that if you give yourself a food borne illness, you are likely to be back home, or headed back when it gets you!

A true food 'poisoning' however will show up quickly. Fresh pork sausage will release some nice toxins. The soap residue on plates and pans is a top causer of trips spent on the throne. These are chemicals and toxins that cooking does not remove. I do not take soap on a back country trip.

So, anyway... You dehydrate the food to remove water. Why? Because bacteria need water to grow. This is why you get the 20 year old Twinkie with no mold. You can do the same by leaving a slice of bread in a nice dry place. Once you bring water back, you allow bacteria to grow. 4 hours at room temperature. Can you go longer? Probably. At home I routinely stretch the rules. At work, never. And really, safety is not the real issue here. The fact is...

You don't need to.

You can soak some things (like a dehydrated casserole) all day and it will still be very crunchy, especially the macaroni noodles. If you just pour in boiling water it will rehydrate perfectly in 15-20 minutes.

Assuming you are going to heat your food, using boiling water and adding it to the food will use less fuel than heating up (to boiling) a partially or even fully rehydrated meal.

Thanks EC. That was a well thought out response and we will follow your advice.

Thanks for the good advice ECPizza.

I doubt I change rehydrating my pizza sauce starting at lunch. Somehow the boiling water before putting it on dough doesn't make sense.