Microbiological evaluation of tofu and tempeh during processing and storage

Abstract

Tofu samples consisting of ‘Fresh Tofu’, ‘Herb Tofu’, ‘Tofu Paste’, ‘Fried Tofu’, ‘Tofu Burger’, ‘Smoked Tofu’ and different types of herbs used for making ‘Herb Tofu’ were analysed for their microbiological load. Tempeh samples consisted of cook water, inoculated beans and fresh tempeh. ‘Fresh Tofu’ and ‘Herb Tofu’ had high bacterial counts (≥10⁵ cfu/g). ‘Tofu Burger’ and ‘Smoked Tofu’ had counts around 10⁴ cfu/g. ‘Tofu Paste’ and ‘Fried Tofu’ had low counts (<10² cfu/g). Cutting board, knife and frequent hand contact with product were the major sources of contamination for tofu. Herbs used for making ‘Herb Tofu’ were highly contaminated (>10⁵ cfu/g). Cook water and cooked beans for tempeh production had lower counts (≤10⁴ cfu/g). Initial count of fresh tempeh was high (about 10⁸ cfu/g). Most products had counts of >10⁶ cfu/g after 7 days of cold storage. The microbiological quality of the product may improve if producers avoid unnecessary contamination during processing.