EFFECT OF DIFFERENT METHODS OF SOAKING SOYA BEANS ON THE GROWTH OF BACILLUS-CEREUS, KLEBSIELLA-PNEUMONIAE AND STAPHYLOCOCCUS-AUREUS IN TEMPEH

Tempeh is usually made by fungal solid state fermentation of soaked and cooked soya beans. In this research the effect of different soaking conditions of soya beans on the growth of Bacillus cereus, Staphylococcus aureus and Klebsiella pneumoniae either alone or with a mixed inoculum of Rhizopus oligosporus and lactic acid bacteria was investigated. Natural acidification did not prevent the growth of undesirable bacteria. The acidification of soya beans soaked in water at 25°C for 24 h prevented the growth of S aureus. To prevent growth of S aureus in tempeh by chemical acidification it was necessary to add 0.6 % lactic and 0.06 % acetic acids and to adjust the pH to about 4.0. Copyright © 1990 John Wiley & Sons, Ltd