 Okay, everybody, Dr. O'Hare, this video we're going to talk about pasteurization, so obviously like the name implies, developed by Louis Pasteur, I believe in the 1860s, mainly to prevent the spoilage of beer and wine, but we now use it for lots of things. And generally when you think of pasteurization, at least the first thing people think of is dairy products like milk. So pasteurization is kind of interesting. It is not a sterilizing technique, it's not designed to be one. So pasteurization has two key functions. Number one, to kill pathogens, right, to kill the food-borne illness causing organisms that are in milk for this example here, and then it's to reduce the spoilage organisms. So generally speaking, when you pasteurize, why wouldn't you try to kill all the organisms? Why wouldn't you try to sterilize the milk, like we actually do in one example I'll share in a moment, or get close to sterilization. That's because it's a trade-off. You want to extend the shelf life of food like dairy, I'm just going to talk about milk. In the shelf life of milk, you want to make sure there's no pathogens in it that can make you sick or kill you, but you still want to taste like milk. So that's the trade-off there. You want to kill as many organisms as you can without greatly changing the product. Like I've consumed quite a bit of raw dairy in my life and I think it tastes different, but it's not wildly different. So that's this idea of pasteurization. It's a trade-off between how many microbes can we kill without changing the end product, the food or beverage that much, right? All right, so a couple of examples here of pasteurization, but I'll give you one first. They're just like stovetop pasteurization. The whole point behind pasteurization is the higher the temperature goes, the less time it takes to pasteurize a food product. So traditionally, pasteurization was 63 degrees centigrade or Celsius for 30 minutes called stovetop pasteurization. We still do that if we take like our raw dairy and we pasteurize it so we can turn into yogurt. That's what we would do, 63 degrees, which is like 145 degrees Fahrenheit. For 30 minutes. So that's just regular or stovetop pasteurization. Then we have this HTST pasteurization is high temperature, short time pasteurization. And that's going to be 72 degrees, only takes 15 seconds. So as the temperature goes up, the amount of time it takes plummeted. So this is going to be like what we would consider pasteurization now, usually high temperature, short time pasteurization. On the right side here we have UHT or ultra high temperature pasteurization. So 138 degrees for two to four seconds generally. And then if this is properly sealed and you put it in sterile packaging, then like it says there are containers, you can go 90 days without refrigeration. This is about as close as you're getting to sterilizing this milk product. So why is this important? If you need to really extend the shelf life or you're going to consume, you're going to buy or sell these products where refrigeration is either spotty or non-existent, that's when you would use this. I've seen a lot of military bases are going to have ultra high temperature pasteurized products on some other countries. Like I've had some students from Germany that say this is much more common there. So you certainly can find these things here in the US as well. So those are the three types of pasteurization, like your stove top, your HTST and your UHT. Don't care about the numbers specifically, but just remember as the temperature goes up, the time can go down. So we talked about the benefits of pasteurization already. We're trying to eliminate pathogens and minimize spoilage organisms. So one just kind of interesting thing, looking at this picture here, this organic valley product, one thing I find a little bit of ironic is that many of your organic products are going to be ultra high temperature pasteurized, which, you know, because lots of people buy organic because they want foods that have been less processed and less adulterated if you want to use that term. But the reason they have to do that is to extend the shelf life because organic products don't sell as quickly. So this is kind of an interesting little tidbit. All right, that's pasteurization developed by Pasteur. Just remember it's not a sterilization technique. It's not designed to be one. Okay, I hope this helps. Have a wonderful day. Be blessed.