Effect of treating with propionic acid, sodium bisulfite and sodium hydroxide on the biosynthesis of aflatoxin on groundnut cake

Aflatoxin free groundnut cake (GNC) pretreated with 0.25, 0.50, 0.75 and 1.00% each of propionic acid, sodium bisulfite or sodium hydroxide at three moisture levels of 10, 15 and 20% was charged with Aspergillus flavus (107–108 spore) and kept in sealed polythene bags or in petri dishes. The propionic acid and sodium bisulfite treated samples were kept for a period of 15 days at room temperature (which varied from 18 to 35°C) in sealed polythene bags. In an another set sodium bisulfite and sodium hydroxide treated samples were kept at 25°C for 25 days in petri dishes. The results showed that at 0.5% treatment level of propionic acid or 1.0% sodium bisulfite at 10% moisture, there was a complete inhibition of mold growth as well as aflatoxin biosynthesis when kept at room temperature. At 25°C the aflatoxin biosynthesis was fully checked with 0.75% sodium hydroxide at 10% moisture and with 1.0% sodium bisulfite at 15% moisture. Out of the three chemicals tested as mold inhibitors, the propionic acid was found to be most effective followed by sodium bisulfite and sodium hydroxide.