Three types of bacteria are used in the production of Swiss cheese: Streptococcus thermophilus,[8] Lactobacillus (L. helveticus or L. delbrueckii subsp.

[11] A hypothesis proposed by Swiss researchers in 2015 notes that particulate matter may also play a role in the holes' development and that modern sanitation, which eliminated debris such as hay dust in the milk, played a role in reduced hole size in Swiss cheeses, or even "blind cheese".

[14] In general, the larger the eyes in a Swiss cheese, the more pronounced its flavor because a longer fermentation period gives the bacteria more time to act.

As a result, U.S. industry regulators have reduced the minimum eye size with which Swiss cheese can receive the Grade A stamp.

[16] Typical annual production of Swiss cheese in the United States is approximately 330 million pounds (150 kt).