The Role Of Bacteria In Cheese
Although cheese making is an ancient art, the role of bacteria in cheese has not always been well understood. It wasn't until the latter part of the 19th century that cheese makers realized that bacteria played a significant role in making cheese, at least to the extent that since there was a certain amount of fermentation present in the process, there must be some kind of an agent, such as bacteria, helping the process along.
It wasn't until the beginning of the 20th century that the role of bacteria in cheese became well understood, along with the knowledge that there were many types of desirable as well undesirable bacteria in milk, and whichever types happened to predominate would strongly influence the ultimate taste of the product. When the wrong types of bacteria predominated, the final cheese product usually was inedible or unmarketable.
The first hint of the role played by bacteria in cheese may well have been during initial attempts to make cheese from pasteurized milk. In the pasteurizing process, the bacteria in the milk is killed off, and any cheese produced from that milk would never ripen. Pasteurized milk can be and is used to make cheese, but the bacteria which allow the cheese to ripen must come from an external source. Put another way, the pasteurized milk is inoculated with friendly bacteria.
Quality Wasn't Always A Constant - When you shop for cheese today, and shop for a particular type and a particular brand name, you can be quite certain what the cheese you have purchased will taste like. The taste does not vary much, if at all. The reason for this is that bacteria in cheese is carefully controlled during the cheese making process. It wasn't always that way, and in years past, a hundred or more, one could not always be certain exactly what the flavor of a given cheese might be. Those making the cheese tried to standardize the process, and in that way standardize the taste of the product, but on occasion the wrong mix of bacteria would prevail, and the taste of the final product would not be as expected.
Cheese making basically involves separating most or nearly all of the water from milk and then letting the milk ferment and age. It is the lactose in milk that is fermented and the fermenting agent is one strain or another of lactic acid bacteria. The lactic acid bacteria in cheese also helps keep pathogenic bacteria, the “bad” bacteria, in check as well as hastening the solidifying process and contributing to the taste of the final product.
Starters Define Taste And Texture - The concentration and types of bacteria used in making cheese are carefully controlled, and cultures of these bacterial types make up what are called starters. Starters are mixed in with the milk to initiate the fermentation and drying process. A starter may be a simple starter, containing a single strain of bacteria, or known proportions or percentages of different strains, or a compound starter, containing a mix of bacteria designed to produce a specific end result. The starters are further categorized as being mesophilic or thermophilic, terms defining the temperatures under which the fermentation and curing processes take place.
Mesophilic bacteria in cheese produce fresh and hard cheeses such as cheddar and Colby, and fresh softer cheeses such as Camembert, Gouda, and blue cheese. Thermophilic starters yield Swiss and feta cheeses, as well as many of the Italian cheeses such as Parmesan, provolone and mozzarella.
While bacteria in cheese has always been with us, and has led to the production of the many different kinds of cheeses we all are familiar with, it has only been during the last century that it became known that the different types of bacteria in cheese more than the cheese making process itself was the major factor in determining the flavor and texture of the final product.