Lactobacillus brevis is a gram-positive bacterium. It can be found in many different environments, such as fermented foods, and as normal microbiota. L.brevis is found in food such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. The hop, which is an antimicrobial bitter flavoring agent in beer, fails to suppress some strains of L. brevis.
Pediococcus is a genus of gram-positive bacterium. Pediococcus is, along with other lactic acid bacteria such as Leuconostoc and Lactobacillus, responsible for the fermentation of cabbage, making it sauerkraut. Pediococcus bacteria are usually considered contaminants of beer and wine, although their presence is sometimes desired in some beer styles.