Mention any four microbes used in household products.

Solution

Microorganisms are widely in used in household products. Some examples include
1. Lactic acid bacteria (LAB) like Lactobacillus acidophilus are added to milk to make curd. 
2 Baker's yeast, that is Saccharomyces cerevisiae is used to make bread. 
3. Leuconostoc and Streptococcus species of bacteria are used to make idli and dosa.
4. Single Cell Protein like Spirulina is used as supplementary food for the source of protein.