AbstractOne important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray‐dried milk, 4–5 log cycles destruction occurred. The results indicate that, the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/°K mole to about 38 kcal/°K