Process cheese foods and spreads manufactured to contain low sodium concentrations (ca 320 mg/100 g or 90 mg/28 g, one serving) and added delta-gluconolactone (0.33%) were resistant to toxigenesis by Clostridium botulinum inoculated at a rate of 1000 spores/g and held at 30°C for 84 d. Low pH values (5.26 or less) provided by delayed acidity development from delta-gluconolactone were influential in the C. botulinum inhibition observed. Disodium phosphate, trisodium citrate, dipotassium phosphate, tripotassium citrate, and sodium aluminum phosphate used in screening tests as single emulsifiers (2.5%) in process cheese foods and spreads allowed toxin formation in many samples prepared. However, some inhibition of toxin formation was indicated for samples emulsified with disodium phosphate, and possibly trisodium citrate.