I read that irradiation of food leads to stuff that can sit weeks on a shelf without rotting. If you cook food, even boil it (and allow it to sit at room temperature) it will rot…within a day or so.
So why does gamma irradiation render stuff immne to decay?
I think the process oght to be used-now that a lot of chicken and beef is contaminated with bacteria, irradiation would be a good way to prevent a lot of food poisoning.
Where? This is likely not actually true.
Nothing. All irradiation does is kill the bacteria and other lifeforms on the food at the moment it’s irradiated. It’s essentially similar to heat treatment in that regard, except it doesn’t cook the food and it may be more effective. It doesn’t change the food in any meaningful way except to make it ritually unclean to the people who have massive religious objections to anything they don’t understand.
To make food last a long time, you have to do two things: Kill all (or at least, the vast majority) of the microbes that are already in it, and seal it off such that new microbes can’t get in (not necessarily in that order). Heat or radiation either one will take care of the first; for the second you need to wrap it in plastic, or put it in a sealed can or jar, or something of the sort (and note that canned foods, sterilized by heat and then sealed in metal or glass, have been around for ages and keep food good pretty much indefinitely).
The advantage to radiation over heat is just that it doesn’t cook the food. Cooking usually causes changes to the chemical structure, and hence taste and texture, of food, and people often prefer the raw forms.
Fruits and vegetables are about the only foods that will last much longer of they have been irradiated than if they are cooked. But that is because irradiation doesn’t cause any physical damage.
Plant produce gets damaged during the harvesting and packing process. In the cases of thing like brocolli the stem is deliberately cut for harvest, for fruits suck as apples the handling process causes micro tears in the skin. All those injuries are pathways for bacteria into the plant, and they cause the produce to decay fast.
Plants have defences against injuries analogous to animal clotting processes, so once a wound is few a hours old it ceases to be a major source of infection/decay. So if you irradiate fresh plants produce after the roughest part of the handling process is over, it will last much longer than either non-irradiated or cooked food.
But that is about the only example where the situation described in the OP is true. Given equivalent handling irradiated meat or irradiated bread, for example, do not last any longer than cooked material.
As I understood, intense irradiation (enough to definiely kill all bacteria in the food) will have a similar effect to heating, although not as strongly. I thoght one comment I read was that irradiated meat was partly cooked, too much irradiation made milk taste carmelized. Makes sense, basically strong radiation is doing what heat does, break apart long and fragile organic molecules.
Mind you, there’s still a big difference between a 2-minute blast that kills all life in a sample, and even the minor (?) radiation overexposure that makes your hair fall out and will leave you dead in a week or two. IIRC, bad radiation burn patients look very much like burn victims or people who have had an extra-serious case of (deep, penetrating) sunburn.
Oh yes, and whichever you do to preserve food, if you do not seal it it will rot.
Even if there wasn’t, it wouldn’t matter: A blast of radiation doesn’t make food radioactive in the slightest. As long as the places where the food actually gets irradiated, and the machinery that generates the radiation, are all shielded and proper safety precautions are taken, no radiation is going to escape into the general environment and cause problems.
Mind you, that won’t stop the protests, but since when has reason ever stopped protests?
Didn’t your momma ever can fruits/vegetables? If you boil it and seal it in a canning jar while it’s still boiling hot, you can store it on a shelf for months.
That’s not what I meant. What I meant was that the doses of radiation being used to sterilize (meat or milk usually) is substantially stronger than the dose we associate with Chernobyl-Japan fallout accidents, and also substantially stronger even than a serious radiation accident (like the Chernobyl emergency workers) where you look fine until you die of radiation exposure in a week or so - as happened to Szilard(?) when he accidentally set off a serious chain reaction with his screwdriver.
No, irradiation DOES NOT create radioactive elements in the food. The food is safe.
In other words, if you put a person through a food-irradiation process, the person would be in very bad shape. Which is only to be expected, really, since the food irradiation process is designed to kill every living thing in what it’s hitting. Likewise, a human dunked in a big pot of boiling water for a half-hour is also going to be in very bad shape.
I don’t think the OP as written actually makes sense. Irradiation is a method of sterilization, so it doesn’t make sense to ask if it’s “more effective than” sterilization. Are you asking how its effectiveness compares to other methods? You mention cooking and boiling, but those may or may not be methods of sterilization, depending on how they’re applied and what sort of germs (if any) you’re intending to kill.
Which has actually happened; there have been a few quite notable worker accidents at irradiation facilities. Each of them involved a worker deliberately bypassing safety requirements and routines, and/or poor maintenance. The IAEA publications website has information about several such.
But of course, there have also been quite a few worker accidents involving high-temperature processes. And I suspect that from a worker safety standpoint, irradiation is probably, on the whole, safer than heat-based sterilization (if for no other reason than that it’s a newer process).
If we’re going to ban machinery based on worker injuries and fatalities, fishing boats would be on the top of the list to be banned, followed by whatever it is that causes most logging injuries (chainsaws, perhaps?), followed by small aircraft.
Forbes article on dangerous jobs, from March 8 of this year. (It surprised me because farming didn’t make the cut. I was certain that was up near the head of the list, but it isn’t even mentioned.)
My point exactly. The person better be dead when the treatment is applied, since we also expect even his intestinal flora to be dead from this treatment.
What I was trying to say is the radiation to sterilize a food sample is a helluva lot stronger than even what we think of as a fatal radiation exposure; they typical ones we think of take days or weeks to kill.
That radiation level does not result in unharmed (sterile but raw) food. From some article I read many years ago, it will result in the sample being partially, slightly cooked. Slight carmelization taste of milk was mentioned as one side-effect.
No doubt of that; I was just making the observation. The articles I linked to are rather interesting (the irradiation ones are Nezvizh, Soreq, and San Salvador) in that in each case, the people involved had to blatantly ignore safety protocols and really WORK at it to get hurt. In the Nezvizh incident, the worker involved would have had to perform some genuine acrobatics to make his way through the ‘safety maze’ and enter the radiation area. They build these facilities with all kinds of safeguards to prevent accidents. The accident rate really is much lower than any other kind of sterilization method.
You have to shake your head at the foolish things people will do sometimes, though.
Take a look at the list in pictures - farmers and ranchers come in fourth most dangerous, just behind pilots, loggers, then fishermen.
You’ve got your nuclear physicists mixed up. You were thinking of Louis Slotin, the second victim of the Demon core.
This has been studied for about 50 years or so, and the biggest objections are that the normal bacteria are killed off leaving room for new unknown bacteria and the radioactive material has to be at processing plants with attendant security problems.
I have read the links posted here, and am curious: what would have happened if in both of these accidents the experimenter had not immediately removed the neutron reflector? Would there have been a meltdown, a nuclear explosion, or what?
We obviously come from vastly different social backgrounds.