Growth and toxin production by proteolytic and non-proteolytic strains of Clostridium botulinum have been followed in 28 cooked puréed vegetables prepared under strict anaerobic conditions and incubated at 30 degrees C for up to 60 d. Toxin production was confirmed in 25 of the cooked vegetables inoculated with a suspension of spores of proteolytic strains of types A and B, and in 13 inoculated with a suspension of spores of non-proteolytic strains of types B, E and F. For both proteolytic and non-proteolytic strains, a trend was identified correlating growth and toxin production with the pH of the cooked puréed vegetables.