Food Irradiation

you today we're going to talk about food irradiation man does that sound scary something you're gonna eat irradiated but the scariness is myth take this example let's say I had a flashlight right and it's shining out light and it shines out light on anything how about on a rock okay when you turn off the light does the rock glow no of course not it's the same thing with food irradiation we put out gamma rays that will kill the bacteria if it doesn't turn the food radioactive the food is the same as the food was before it's just it's a way to kill the germs the bacteria the mold the viruses the other things that could be inhabiting this item an item you want to eat to make it safe so how do we do this we take a radioactive substance and gamma emitter one example is cesium 137 it has a half-life of 30 years and what it does is it decays by a beta decay into another element which goes into an excited state that excited state then emits a gamma of 0.6 mega electron volts it's those gamma rays that go and would hit the substance you're trying to sterilize even more common is cobalt 60 it has a shorter half-life meaning the food a radiator you build in five point something years is only going to be half as effective but it has much higher energy gamma rays in fact you get to sort of for the price of one that beta decay goes into nickel and then it gives you two gammas of over one MeV each this is the most common type of food a radiator you take the substance that you want to sterilize and you put it in there you expose it to the gamma rays it kills the bacteria kills the fungus it kills the viruses you take it out and now you will have a much longer shelf life there's a great example of this have you ever had strawberries and you left them in your refrigerator for a couple days this is often what they look like very common it's a fungus and mold other things that grow on your strawberries you don't want to eat that so you buy them in the store you better eat them right away stores can do various things to try to make the strawberries last longer because after all this is the picture of the strawberry you want to eat now there are two choices you could spray a bunch of chemicals onto the food right you can put on fungicides and mold removers and antibiotics and all sorts of stuff you get a coating this delicious strawberry your mom always told you wash your food before you eat it not a bad idea maybe you would wash it all off or maybe it would just look so delicious you pop it in your mouth or you could irradiated if you were radiated no problem popping it right in your mouth the gamma rays killed the bugs they didn't stay around I'd much rather have and a radiated strawberry so how do you know if your foods been treated with the chemicals which could be very bad if you ate them before you clean them off the surface or if you had food that was sterilized and kept with a longer shelf-life by radiation the key is looking for this symbol this is the red aura symbol and indicates that things have been treated by gamma rays to kill off the unwanted bacteria and other items now there's always been the question of does it alter the food in some other ways are there negative consequences after all if you put enough gamma rays through that can kill the bacteria Yeah right the scam array comes through it's going to affect the DNA that's inside here the bacteria is going to die what about some of the the proteins right the the carbohydrates the other items that were in the food itself won't it break some of them up in fact some people say won't this make free radicals well the answer is it will make some of those Oh free radicals are bad well they are very bad if they're in your bloodstream if they're in your flesh if they're in their body they can cause genetic damage but remember you're gonna eat this food you're not taking the food and injecting it with a needle into your bloodstream you're putting it in your stomach those free radicals aren't going to live through digestive systems and stomach acids and everything else in fact much of the food you eat has all sorts of broken up proteins and other things because you cook most of it and in that process you make all sorts of radicals and other things too but when you digest it and eat it and chew it up and swallow it this type of stuff these quote negative consequences the things that would happen to the substances in the food from the irradiation those are not going to be anything to be concerned about for your health there's another example virtually all the spices in the world are irradiated first you ever wondered why you can keep black pepper around on your shelves for years and it doesn't all turn moldy or start rotting or have things growing in it it's because it's been irradiated it's fairly common and something that the public is afraid of but should not be hey let's go and actually see a food a radiator in action all right we are here today at the nuclear radiation lab with my friend senior research scientist stoyan Tasha thank you for sitting here so we are here in his lab because he studies food irradiation and we actually have a food a radiate tour so Stein can you tell us some about this device and this is canadian-built machine what with 24,000 qt Wow 24,000 using cobalt extremely safe to work that's right so our dose right here is Oh just a tiny bit above background yes right and of course inside the device where you'd actually be a radiating things that is not someplace we would want to stand up so what we have here is you're actually raising the shielding right yes okay the radiation chamber now you might say oh my gosh we're all getting irradiated but that's not the case the radiation source is still down inside the chamber where it's very safe what we do is this is the chamber where something would get irradiated and then you put it back in so historians adding liquid nitrogen because in studying the effects of food irradiation it's important to separate that from temperature effects so if you can keep things frozen then you can see what will happen not because maybe they got warm but because they were actually kicked by the gamma rays is there anything in there besides the liquid nitrogen any Sam yes the same okay he say so now that's the sample that will be ready and again our dose has never changed because the radiation source is inside and now we put this and all of this shielding on top will go back into the irradiation chamber I think this is a particularly interesting example here are a variety of medicines and if you might imagine if you have cancer treatments and they're doing radiation on you you might wonder what will the medicine you're also taking be changed because of the radiation treatment right and in this way one of his research projects is actually to determine that because he can expose the medicine into a similar environment of a radiation treatment that a patient would have and then find out afterwards if the medicine has changed its efficacy and its use in its chemical composition I think another one which you like showing off is the grilled beef steaks these are supposedly delicious right do you even one before okay so these are what we send up in space with our astronauts and it's very important that they don't get any kind of infection they don't get any disease they don't get food poisoning when you're up in a space capsule or a space station so you want to make sure that the food has been Arabia it's all the bacteria have been killed it doesn't hurt the food the food doesn't become radioactive but what happens is that all of the germs that might be in it from processing from the cow itself get cleaned off and you can tell because this then turns a color there yes before radiation is here oh this is indicator well now it's alright and so this has no bacteria left alive in it and it becomes you know very very safe to eat and it's not just astronauts right yes there are people that have had transplants yes in the Soviet time oh the foot of the this around five million are me so use in ready eight foot so the Soviet Army is always is radiated keep alert no I don't know we don't know no but but the key was that it would you don't want your troops to get sick from eating bad food so you might as well one way to really sterilize it and to do so without affecting the quality of the food is food irradiation when we radiate is dangerous but after second the food is absolutely not radioactive because the energy is 1.3 mm after after 6mf we start induced radiation that means we are absolutely safe absolutely it's a nice analogy of this is if you shine a flashlight on something it doesn't start giving off light it's the same thing here you hit these with gamma rays because it kills the bacteria it doesn't mean this gives off gamma rays just like a thing that got hit by any other type of light after all gamma rays are just very high-energy light so what we do when we radiate food is we kill the bacteria but then the food is not any more radioactive or different than it was before you put it into the food or radiator so what's actually inside this machine this of course this isn't really made out of cobalt-60 or I wouldn't be touching it like this okay but inside there each of these rods is actually a rod made of the radioactive element cobalt-60 and therefore a sample the food the state the Medicine something else that dr. Tosh cough is testing is in this field where all of these are emitting gamma rays so this is really neat to see what would be the actual device in here this is just made out of a copper but the actual thing would be made out of the radioactive elements themselves well the nice thing is this machine is foolproof there's no way you can actually physically like put your hand in where the radioactive sources yes and the most important is that the LED stop already coming from this machine right this is a special room with a special reinforced floor special steel platform because literally we have this thick of lead on all sides underneath and around this and lead is heavy so this room is very special and we also have of course all sorts of safety guards and automatic alarms and barred windows although in reality it's a little bit silly because I can't imagine anyone lifting this many tons of lead out of here or even wanting to but we can be safe so we will be safe and that's what you need to know about food irradiation [Music]

Channel: Illinois EnergyProf

Views: 39,798

Rating: 4.8975034 out of 5

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Id: BRMG5SsbYkY

Length: 14min 50sec (890 seconds)

Published: Tue May 14 2019