What is the difference between Bioburden and Microbial limit testing (MLT)?

Dear Friends,

In microbiology, we generally use two terms, bioburden and Microbial limit test (MLT). Do we know the difference between Bioburden and Microbial limit testing? Here is a little explanation about Bioburden and MLT testing which you can understand very easily.

Bioburden: The term bioburden means total bioload (living microorganisms) on the surface or within the material. It is a combination of bacterial count and fungal count and generally TVAC (total viable aerobic count) term is used for that. Bioburden is performed for non sterile material, unfiltered or filtered solutions. Bioburden is a quantitative testing in which we only detect number of colony forming units (cfu).

Membrane filter showing colony forming units

Microbial Limit Testing (MLT): Microbial limit testing comprises of detection of total aerobic microbial count (TAMC) and total yeast and mold count (TYMC) seperately in the material. MLT is performed for non sterile materials. MLT also includes detection of specified pathogens which means MLT is quantitative as well as qualitative testing. Quantitative testing is related to only the counting of number of cfu's and qualitative testing is related to detection of specified microorganisms in which we only detect whether the specified microorganism is present or absent.

Mannitol salt agar showing growth of Staphylococcus aureus

Thanks...