Influence of most-probable-number method and container perforation numbers on fungal population density during tempeh production

Abstract

Tempeh is a collective name for a sliceable mass of precooked fungal fermented beans or some other food processing by-products bound together by the mycelium of a living fungus (mostly Rhizopus spp.)(Nout and Kiers 2005). Tempeh has gained world-wide acceptability for its multiple health benefits. Generally, a good quality fresh tempeh is a compact and sliceable mass of processed raw material covered, penetrated and held together by dense nonsporulated mycelium of the fungus. Several containers made of leaf, plastic, wood or stainless steel is used eventually for tempeh production at cottage and industrial level. The limited air in a closed tempeh container significantly altered the tempeh quality at harvest (Aoki et al. 2003, Steinkraus 1996). Perforation of container for aeration upon maintaining adequate moisture in the raw substrate is a technological intervention to expedite tempeh production (Wadud et al. 1986). Hence perforation number as function of container size may be critical for fungal proliferation in scaling up of tempeh commercially. However reports on effect of container perforation on tempeh production are meagre.