New Techniques for Estimating Fungal Biomass in Foods
Viable counts estimate the number of colony-forming units (cfu) of fungi, which may be fragments of mycelium of widely varying dimensions, one or several sexual or asexual spores or yeast cells. Factors affecting viable counts include the degree of homogenization to which a sample has been subjected, the technique, medium, diluent and temperature of incubation as well as the history of the food before examination. Mycelial fragments in particular are likely to lose viability rapidly during storage of foods at reduced aw.
Viable counts give no indication of the content of dead fungal biomass, which is useful for retrospective information concerning the quality of raw materials used in processed foods. Even foods that have received minimal treatment may contain significant proportions of non-viable mycelium.
When fungal counts are determined to assess the shelf life of products, there is a need to know if the fungi detected are capable of growing in and spoiling the food in question. Hence, tests for specific metabolic activity and/or specific groups of fungi may be more useful than total viable counts.
KeywordsHigh Performance Liquid Chromatographic Detection Time Viable Count Muramic Acid Mold Count
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