Based sort-of on this thread I was wondering about a reverse version of that question concerning cooking. Strictly GQ, not a CS query.
My mother has a major phobia about un-freezing and then re-freezing food. All food. I understand the problem with meat/fish or other food products with certain textural issues, and, perhaps, bacterial issues. But it certainly doesn’t apply to soups, chilis or other food items that want to be served leftover, the next day or so, and freeze perfectly fine - or does it? I never thought so. When she would complain about my wife refreezing the spaghetti sauce, I pretty much ignored her.
So then she came in on a new tack and pointed this out. Whenever the missus makes up a big pot of sauce, we eat some, put the rest in freezer containers and have 3 or 4 dinners out of it. When we’re down to the last of it, and it’s time to make a new sauce, whatever remained of the last one goes into the new pot - got it? Over and over and over. You’re cooking 20 year old sauce, sez me mum. Well, yeah, I guess I am, sez I. But it’s cooking for hours and hours, so there can’t be a problem - it’s tomato sauce!
Well. It did make me wonder. I know (I’ve heard ;), that is) that there are sour-dough starters for bread that can be over a hundred years old, and sour-mash whiskey is kind of the same deal. So what about my wife’s pasta sauce. Are we making sour-mash bolongese sauce, and should I make some sour-dough pasta to go with it (hmmm, I guess this is sort of CS :p), or are we contributing to the delinquency of a very mature bacterial colony? And how long before it catches up with us?
[QUOTE=Backwater Under_Duck…or are we contributing to the delinquency of a very mature bacterial colony? And how long before it catches up with us?[/QUOTE]
Eek “Attack OF The Killer Tomato Sauce”
Sorry, I cannot advise, but I shall certainly be following closely, being failry casual about what goes into soup and so on myself.
As long as you are boiling the sauce every time you start over you are most likely killing any harmful bacteria that might have been in there. And if you freeze it right after use (as opposed to, say, leaving it out on the counter overnight and freezing it the next day) there is probably not enough time for bacteria to get enough of a head start before their growth is stopped by the freezing.
For the record yeast cultures are not usually boiled in between, which is why the same culture can persist indefinitely.
Wow, two cooking questions in one day, that I can help with!
When your wife freezes the original batch of sauce, is she freezing it all together, or is she freezing it in meal-size portions? That can make a difference.
For purposes of restaurant cooking, the Washington State Department of Health tells us professionals to never reheat something more than once. So we can reheat yesterday’s leftover soup, for example, but we have to throw away anything that is leftover from the second heating.
The reason given has to do with the total amount of time the food spends in the “danger zone”. The danger zone is that temperature range between 40 degrees and 140 degrees Farenheit (5 degrees and 60 degrees Celsius), in which bacteria can grow. Reheating food takes time, obviously, and the food is potentially dangerous while its temp is in the range listed.
So let’s say your ingredients come out of the refrigerator at 40 degrees. The temperature starts rising as soon as you take the stuff out. And we’ll say it takes about 30 minutes of prep time, including cooking, before the food reaches 140 degrees. The food is served, and again, the temp starts dropping as soon as you remove it from the stove or oven. You eat the food, then put it away in the refrigerator or freezer. Depending on the quantity, it can be hours (counting from when the food first dropped below 140 after cooking) before the temp is lowered to 40 again.
Some time later, you decide to reheat the food. The cycle starts all over again, and the food spends another two hours or so in the “danger zone”, while it’s being brought up to 140 and and then brought back down to 40.
So overall, you’re keeping this food in the “danger zone” for quite a long time. And any time the food is in that zone, it has the chance to pick up bacteria and foster its growth. By avoiding repeated heating and cooling cycles, you reduce the opportunity for bacteria to grow. There is always the chance that the food won’t heat evenly, and that a portion of the food won’t reach 140 degrees and some dangerous bacteria might survive to be eaten by you or somebody else. Keep in mind that a child or an elderly person is going to be far more susceptible to that bacteria than a healthy teenager or adult in the 20-50 age range (remember the E.Coli situation - it was mostly children and seniors who got sick). Bacteria that has little effect on you could be debilitating to a child or senior citizen.
Now, to specifically address the example you gave, you’re probably safe. Tomato products like spaghetti sauce have a very high acid content, and that acid greatly hinders the growth of bacteria. The little germs don’t like it. Still, it’s best to play it safe: don’t freeze the whole big batch in one container after it’s first made. Freeze it in smaller, meal-size amounts, and only thaw and reheat what you need for a meal.
While I’ve been known to do similar things with various recipes, you should probably be aware that the theoretical concern is twofold: spores and preformed toxins.
Preformed toxins are chemicals produced by bacteria, and while many are inactivated by sufficient boiling, not all are. Botulism toxin is moderately thermostable, for example. Since toxins aren’t alive, they can’t be killed, and the part that isn’t consumed [probably in dises too small to cause serious illness at first, but later, who knows] could accumulate from batch to batch
Spores are ultra-tough bacterial “seeds” (well, close enough). They are basically bacterial survival capsules, and many can survive not just boiling but antiseptics and even high pressure, high temperature autoclaving. They may take a bit to ‘wake up’ but they might have ample growth time in a long slow simmer.
Put those two factors together, and add the fact that many bacteria can survive in the cooler parts of a simmering pot, and you see the risks.
I don’t want to make you paranoid. I’m not inclined to ultrafastidious germ phobia at home (work is another story). I’ve been in too many countries in too many situations where “hygiene” consisted of water-- not necessarily potable water, but enough to wash with. Our species evolved under conditions that scare even me sometimes (though life expectancy wasn’t always anything to write Methusalah about) We wouldn’t have some of my favorite foods without fungal and bacterial contamination, so you know our ancestors tried some pretty heady stuff and liked it (Bread, cheese, wine, mushrooms, cheese, beer, truffles… it’d almost be easier to make a fine meal entirely from microbially contaminated foods than without them)
I just thought I’d tell you the medical risks, so you’d know. Personally? If your family sauce is good, I’ll be there with with a bib on, taking seconds.
The fact that you’ve been eating it for twenty years without any apparent ill effects should tell you that you’re doing it right.
I disagree. I think you’ve been VERY lucky. Check out a graphed curve on bacterial reproduction in food that’s been out for a bit - It looks like a rollercoaster at Six Flags.
A neighbor DIED from eating improperly ‘maintained’ meat at a local Mexican place a couple of years ago. We clean the fridge OUT every couple of weeks. I’d purge the stock every now-and-then, if it was me.
Here’s a short primer:
http://www.fsis.usda.gov/Frame/FrameRedirect.asp?main=http://www.fsis.usda.gov/oa/FAQ/spoilage.htm
I think you are being a bit alarmist. As long as you rapidly defrost, and rapidly freeze, those bacteria aren’t going to take over the world. You bushel it up before you die, as my gran you used to say.
Very good. Interesting replies. I don’t like to be too alarmist with my food, but I don’t like getting sick either. The last 2 times I was at Dodger Stadium, I definately went down the next day after eating a few of the famous Dodger Dogs. I think it was the onions at the condiment bar. I’ve sworn off those.
But we are re-freezing dinner size portions of sauce, not large pots, and when the last 2 cups or so of leftover sauce go into a new pot, it will cook for 3-4 hours before coming out again. Unless I’m unwittingly introducing something un-killable into the sauce I guess it’s okay.
This time of year it’s especially good. We use the fresh tomatos from the garden. Wowzers!
[QUOTE=Backwater Under_Duck]
Based sort-of on this thread I understand the problem with meat/fish or other food products with certain textural issues, and, perhaps, bacterial issues. But it certainly doesn’t apply to soups, chilis or other food items that want to be served leftover, the next day or so, and freeze perfectly fine - or does it? QUOTE]
I had to take a course on microbiology once, because that was the one often at that time period and one of several things I remember. Like in that Dial commercial-“You’re not as clean as you think you are”, germs get everywhere and a lot of them survive quite well in a freezing environment. Every time someone dips into a sauce for a taste, they add their germs to the prevailing mess. BTW - I got the impression that these germies like a wet environment, the wetter, ther better. 
:eek:
I think part of your confusion is the sour dough yeast and the mash yeast. Yeast is a special breed of organism as each particular strain will have a by-product that has a differing flavor. In fact, a fair number of yeast strains, *lactobacilli * strains (sour cream/yogurt), and aspergillus strains (soy sauce) used in the production of food are developed over generations, and protected as company secrets. These organisms are not harmful, and they create the recognizable flavor distinctive of these foods. Moreover, the organisms themselves are killed off before the food is consumed, unlike your guys.
I don’t think what you’re doing is entirely safe. In fact, I think your mother is partly right.
She’s right, in that you are indeed cooking 20 year old spaghetti sauce. Let’s say that twenty years ago you picked up a bacterial colony on the counter when you were cooking the original batch. Now I’m assuming (probably wrongly) that you put meat in your sauce. Meat is more highly contaminated that the other ingredients, so let’s just say you threw in a bit of sausage that happen to contain E. coli. Generally *E. coli * s harmless, so he just hangs around in the sauce doing a little E. coli dance, and reproducing himself every 20 minutes. Moreover, his offspring are doing the same thing .
So now you cook you sauce. This is the fist time, so you really boil it well and you kill off 99 % of the* E. coli.* It is almost guaranteed that when we cook we do not cook long enough at high enough temperatures to kill off all the bacteria.
So now you only have one guy left. However, each time you thaw you are slightly less careful. So now your one has become 100. But you make another batch, killing off 99% and now your down to one again. This continues for the next 20 years. And you always have you friend with you each spaghetti night.
But the safety issues only comes in because you are continuing to use the same sauce ad infinitum. Eventually you may pick up something nasty. Especially if you pick up a spore producer that won’t be killed with heating alone. This guy is just going to continue to reproduce because you can’t kill him, until his levels are high enough to cause illness. Also remember that all toxins aren’t heat labile. So even if you cook off the bacteria, you can leave toxin. Over many generations, this too could build up enough to make you very ill.
Now keep in mind, Microbiologist tend not to generally concern themselves about getting sick due to bacterial contamination in food. So I would simply recommend that you start a new batch when the old one is done. Tomato bases are not very friendly environments to bacterial colonization, due to the osmotic pressure and pH, so it should be quite safe.
I agree with the others that posit that this is A Bad Idea.
It’s called “the cycle of contamination”, and it should be broken. I can’t believe it adds much, flavor- or quaility-wise, to your sauce to have 1 cup from the last batch mixed in. It COULD add much contamination-wise, and if you do it every time, you never break the cycle.
Seems a lot easier to not worry about it and throw that last cup away and start from scratch next time.
Wouldn’t the sauce being diluted and mostly removed counteract this? Chances are that one little ecoli is gonna get eaton before he makes it to the next batch. Same with any toxins. they’ll be heavily diltued the next batch.
Most of the sauce eaton will be new. Assuming 1/4 of it makes it into the next batch 1/16 will be 2 batches old, 1/64 3 batches old, 1/256 4 batches, 1/1024 5 batches old, In other words most of the sauce is new.
Slightly OT, but I remember this from Reader’s Digest several years ago:
(paraphrasing, not me)
Once I was making a homemade pasta sauce early in the morning for some guests that night. Only, when I was done with the sauce and turned off the stove, I left it there, and forgot about it until it was time to make dinner many, many hours later. Oops. I called poison control, and explained the situation. They told me that as long as I boiled it for 15 minutes, everything ought to be okay.
Dinner turned out great. Sauce was excellent, and the guests were impressed. As I was washing dishes, the phone rang, and one of the guests answered it. Imagine my embarrassment when the guest announced in front of everyone, “That was the poison control center. They asked if the pasta sauce came out okay!”