The second most popular and most frequently used starter culture after the mesophilic type is thermophilic bacteria. They have a number of features of use and production procedures.
Unlike the more common mesophilic ferments, which are added to milk heated to 25-30 degrees Celsius, thermophilic “tolerate” 30-40 degrees and more. Less susceptibility to temperature conditions makes the latter type of cheese ingredient indispensable in the production of so-called extract cheeses, very popular in Italy, as well as reheating varieties. These include the varieties "Mozzarella", "Provolone", "Romano" and various varieties traditionally produced in Switzerland.
The main strains of bacteria used in the preparation of thermophilic starter cultures are Streptococcus thermophilus, Lactobacillus delbrueckii ssp.bulbaricus and Lactobacillus helveticus. They survive and interact perfectly with milk at temperatures up to 65 degrees Celsius. At a lower temperature, mixing of thermophilic starter cultures with mesaphilic ones is not excluded.
If you want to make a simple homemade cheese or a semi-hard version of it like "Gouda", then you simply do not need thermophilic starter cultures. The same is true for varieties with different types of mold - white, blue, green or red-orange. In this case, you will only need to purchase a regular mesophilic starter culture.
