Effect of metabisulphite on sporulation and alkaline phosphatase in Bacillus subtilis and Bacillus cereus.

The effect of metabisulphite on spore formation and alkaline phosphatase activity/production in Bacillus subtilis and Bacillus cereus was investigated both in liquid and semi-solid substrates. While supplementary nutrient broth (SNB) and sporulation medium (SM) were used as the liquid growth media, two brands of powdered milk were used as the food (semi-solid) substrates. Under both aerobic and anaerobic conditions, B. subtilis was more resistant to metabisulphite than B. cereus while the level of enzyme production and spores formed were generally higher under aerobic than anaerobic conditions. The metabisulphite concentrations required to inhibit spore production as well as alkaline phosphatase synthesis/activity were found to be relatively low and well within safety levels for human consumption. It is concluded that metabisulphite is an effective anti-sporulation agent and a recommendation for its general use in semi-solid and liquid foods is proposed.