Effect of bovicin HC5 on growth and spore germination of Bacillus cereus and Bacillus thuringiensis isolated from spoiled mango pulp

Abstract

Aims: To use bovicin HC5 to inhibit predominant bacteria isolated from spoiled mango pulp.Methods and Results: Bovicin HC5 and nisin were added to brain heart infusion (BHI) medium (40–160 AU ml )1 ) or mango pulp (100 AU ml )1 ) and the growth of Bacillus cereus and Bacillus thuringiensis was monitored. Cultures treated with bovicin HC5 or nisin showed longer lag phases and grew slower in BHI medium. Bovicin HC5 and nisin were bactericidal and showed higher activity in mango pulp at acidic pH values. To determine the effect on spore germination and D values, mango pulp containing bovicin HC5 was inoculated with 10 6 and 10 9 spores per ml )1 , respectively, from each strain tested. Bovicin HC5 reduced the outgrowth of spores from B. cereus and B. thuringiensis, butthermal sensitivity was not affected.Conclusions: Bovicin HC5 was bactericidal against B. cereus and B. thuringien sis isolated from spoiled mango pulp.Significance and Impact of the Study: Bacillus cereus and B. thuringiensis had not been previously isolated from spoiled mango pulp and bovicin HC5 has the potential to inhibit such bacteria in fruit pulps.