Understanding the Role of Bacteria in Cheese Making: A Comprehensive Guide

Introduction to the Bacterial Role in Cheese Making

From artisanal to mass-produced, cheese is a beloved dairy product worldwide. Its rich flavors, textures, and aromas are largely due to the microorganisms involved in the cheese making process. Bacteria play a pivotal role in transforming milk into the diverse array of cheese varieties. This guide will delve into the specific bacteria used to make cheese, their functions, and the impact they have on the cheese's flavor development and characteristics.

Key Bacteria in Cheese Making

Lactococcus lactis is a prime example of a bacterium widely used in cheese making. It is utilized to produce various types of cheese, including Cheddar, Colby, Cottage Cheese, and Cream Cheese. When introduced to milk as a starter, Lactococcus lactis uses enzymes to convert lactose into lactic acid, producing energy molecules called ATP. This process is crucial in the fermentation stage of cheese making, which contributes to the cheese's texture and taste.

Other Bacterial Cultures in Cheese Making

).'Lactobacillus plantarum', 'Lactobacillus brevis', 'Lactobacillus helveticus', and 'Lactobacillus lactis' have been discovered in Cheddar cheese and are believed to play a role in the flavor development process. Some strains of these organisms and other lactobacilli may also contribute to the development of off-flavors in ripened cheese.

Mesophilic cultures are essential for the production of many types of fresh, young, and medium-aged cheese, including Cheddar, Gouda, and Chèvre, as well as washed and bloomy-rind cheese like Muenster and Camembert. The bacteria in mesophilic culture work within a temperature range of 62°F to 102°F, with optimal activity at around 84°F to 86°F. This process is vital for the consistent and controlled development of the cheese's flavor and texture.

Thermophilic Bacteria in Cheese Making

Thermophilic starters, which must be cultured before being added to milk, include members of the Lactobacillus and Streptococcus families. Swiss cheese, for instance, uses Propionibacter shermanii, which produces carbon dioxide gas bubbles during the aging process, giving Swiss cheese its distinctive holes or "eyes."

The Diversity of Cheese Bacteria

Over 400 varieties of cheese are made today, and the bacteria used vary depending on the type of cheese desired. Some cheese varieties use fungi instead of or in addition to bacteria. Some of the bacteria used include:

Lactobacillus lactis
L. delbrueckii
L. bulgaricus
Streptococcus thermophilis
Propionibacterium shermanii

Thermophilic Bacteria in Mediterranean Cheeses

Most Mediterranean cheeses are made by thermophilic bacteria, which include:

Streptococcus salivarius subsp. thermophilus Lactobacillus delbrueckii subsp. bulgaricus Lactobacillus helveticus

Mesophilic Bacteria in Continental and Cottage Cheeses

Many continental and cottage cheeses are made from mesophilic bacteria, which include:

Lactococcus lactis
Lactococcus lactis subsp. cremoris
Lactococcus lactis biovar. diacetylactis
Leuconostoc mesenteroides subsp. cremoris
Lactobacillus plantarum
Lactobacillus rhamnosus
Lactobacillus paracasei
Propionibacterium freudenreichii subsp. shermanii

The use of these bacteria in cheese making ensures the development of unique flavors and aromas that contribute to the diverse palette of cheese varieties. Understanding the role of bacteria in cheese making is essential for cheesemakers, enthusiasts, and consumers alike. Each type of microorganism brings a unique set of characteristics to the cheese, making the process of cheese making both an art and a science.