Louis Pasteur, which is why we call it 'pasteurising' the milk, by heating it to 72oC.
Pasteurising of milk is to make it safe to drink. Drinking raw milk (before pasteurisation became standard practice) resulted in many cases of bovine tuberculosis in humans. Thankfully, modern pasteurising practices has reduced Bovine TB in today's populations in the western world, at least.
Pasteurising kills all microorganisms in the milk then you introduce the bacteria that makes the yogurt.
Harmful food microbes, including bacteria and viruses, are killed when heated to 65°C (150°F).
Deep freezing, pickling, pasteurising, ultra heat treating, salting, canning, drying, boiled in sugar (Jam), smoking.
Bacteria are only able to live in a very narrow temperature range. Too high, or to low a temperature, and they perish. This is why pasteurising milk stops it going bad too quickly.
Warm cold milk slightly is one way to make it lukewarm. Or leave the too warm milk to cool to lukewarm. Or add cold milk to reduce the too warm milk to lukewarm. I'm not sure whether the question is actually about pasteurising raw milk?
By heating the loop before using, all bacteria which may be on it will be destroyed. It is allowed to cool before using and it is sterilized again after use.
It is critical to cool the inoculating loop before collecting the culture since retrieving the culture while it is still hot will result in the culture being scorched and destroyed. When the heated loop comes into contact with the liquid broth culture, part of the broth (and bacteria) will momentarily boil, resulting in a bacterium-containing aerosol. These microorganisms in the air may enter the student's respiratory tract or settle on her skin.
There are a couple of methods for pasteurisation: 1. Batch pasteurisation In this method milk is heated in a tub while stirring to not less than 63°C for at least 30min. This is followed by cooling within 30min to below 5°C. This method is less commonly used today. 2. High temperature short time pasteurisation Using a continuous system (stainless steel pipelines) milk is pumped through heat exchangers for pasteurisation at 72°C for 15 seconds. After this it is cooled down to below 5°C quickly through heat exchangers. The more the temperature is increased, the less time is needed for the pasteurisation to be effective. After pasteurisation, the standard test to see if it was effective is the phosphatase test.
Keep it as cold as possible (put the container into a bucket of cold water as soon as you finish milking) and then just strain through a coffee filter or (as a coffee filter does a great job but takes forever!) or a very fine mesh strainer. We have drunk goats' milk for 17 years now without any ill effect and we have never bothered with pasteurising. We like our milk raw and whole as nature intended. HOWEVER, I wouldn't give raw milk to babies and very young children or people with weakened immune sytems . It's up to everyone to decide for themselves whether they need the entirely bacteria-free sterility of pasteurised milk and if neccessary they should ask a health professional for advice. ALSO, you probably won't be able to sell raw milk in most places, so you need to check with someone like Trading Standards or the equivalent. But you can always sell for pets and there's a whole lot of thirsty puppies out there!!
Coffee with milk contributes abrasives that would worsen arthritic conditions already being experienced by the arthritis sufferer, though the consumption of coffee/cafiene itself may not imediately/directly increase the pain. Black coffee might not worsen the problem for an arthritis sufferer, but when milk is added to the hot water it becomes abrasive,(perhaps because of the coarse calcium). For that matter Tea might also contribute to the sufferers woes, then again, milk itself has a coarse form of calcium( better suited for calves, funny that, than for humans) that would already have become an abrasive due to the heat employed during the pasteurising process. In contrast, by placing 3 prunes in a mug, filling the mug with boiling water and allowing this to stand (covered, perhaps with a saucer) overnight, then drinking this in the morning, everymorning, will provide relief for the arthritis sufferer,due to natural lubricants, present in the prunes,being provided for the body's joints. For reference, read "Fit For Life" by Harvey and Marilyn Diamond, this explains coarse calcium aswell as calcium humans can benifit from, namely RAW sesame seeds, if a lack of calcium is the main concern/reason for adding milk to coffee/tea. Best regards, Tuffy.