Enterotoxin-producing strains of Bacillus thuringiensis isolated from food

Strains of Bacillus thuringiensis were isolated from various food items (pasta, pitta bread and milk) and were found to belong to either H-serotype kurstaki or neoleonensis. The strains were bioassayed against Pieris brassicae and insecticidal activity of strains was found to correspond to the presence of the cry1A-gene. All strains, except one, were found to express cytotoxic effects on Vero cells as an indicator of enterotoxin activity. Further, the B. thuringiensis strains HD-1 (serotype kurstaki), NB-125 (serotype tenebrionis) and HD-567 (serotype israelensis ) which are used commercially for insect pest management, were also found to have cytotoxic effects on Vero cells.