Yeast and Mold Test

Dilutions of the original sample are plated on DRBC agar and incubated at room temperature (20°C to 25°C) for five days.

Standard Microbiology Equipment

Compendium of Methods for the Microbiological Examination of Foods 4th Edition: Chapter 20
FDA BAM, Chapter 18

CFU/g

100g

These are usually considered significant spoilage organisms in high acid or low water activity products. They can also serve as quality indicators in grain ingredients and products.

Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time; they invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Their delectability in or on foods depends on food type, organisms involved, and degree of invasion. The contaminated food may be slightly blemished, severely blemished, or completely decomposed, with the actual growth manifested by rot spots of various sizes and colors, unsightly scabs, slime, white cottony mycelium, or highly-colored sporulating mold. (BAM Online 2001 Chapter 18 https://www.cfsan.fda.gov/~ebam/bam-18.html)