Growth of, and aflatoxin production by Aspergillus parasiticus when in the presence of either Lactococcus lactis or lactic acid and at different initial pH values.

Aspergillus parasiticus was grown in a modified Lab-Lemco tryptone broth both as a single culture and in association with Lactococcus lactis. Total aflatoxin (B1 + G1) production was higher in the mixed cultures. This stimulation persisted when different batches of media, inoculation procedures and makes of ingredients were used. Aflatoxin yields increased in media with an initial pH of 4.2 compared with a pH close to neutrality. Hydrochloric and/or lactic acid had little effect. The substitution of half the carbon content of the medium by lactate resulted in stimulation or reduction on aflatoxin production when the initial pH was 4.2 or 6.8, respectively.