The big difference between the two is simply that Sterilization kills virtually all microorganisms and pasteurization kills vegetative or hibernating spores or bacteria.
When dealing with many types of mushrooms and fungi, it helps to have a controlled setting with controlled atmospheres and environments to avoid unwanted growths and contamination from outside entities, other bacteria, or even other types of fungi like mold. This is where Sterilization may be preferred, especially with very sensitive and delicate strains of peculiar fungi.
Some mushrooms don’t need nutrient dense food, for instance, Oyster mushrooms can use wood chips. When dealing with non nutrient dense substrates, as long as you’re not adding supplements or fertilizer, you can simply pasteurize the substrate with hot steamy water. Essentially washing the wood chips with hot water and leaving them to soak for a few hours. Then you can grow your oyster mushrooms on the pasteurized substrate.
We mention the nutrient dense food because some food that isn’t nutrient dense does not have enough nutrients for things to grow. So there’s not a large risk for contamination from other strains of fungi or bacteria. That’s why pasteurization is the quicker and easier method to ensure enough unwanted foreign microbes are eliminated or reduced.
For sterilization, there are many methods that range from pressure cooking to various forms of heat treatment in austere environments. This helps to kill virtually all microorganisms, and there’s plenty of sterilization methods online.
Growing is basically farming, so it’s a mix between an art and a science. Find what works for you and keep at it.
If you have anything to add, feel free to comment down below.