Bactericidal effect of bovicin HC5 and nisin against Clostridium tyrobutyricum isolated from spoiled mango pulp

Aims: To test the effect of bovicin HC5 - a bacteriocin from Streptococcus bovis HC5 - against the strains of Clostridium tyrobutyricum isolated from canned spoiled mango pulp. Methods ans Results: Bovicin HC5 [40-160 arbitrary unit (AU) ml(-1)] reduced the specific growth rate and increased the lag phase duration of the bacterial isolates inoculated in brain heart infusion media at 30 degrees C. The inhibitory activity of bovicin HC5 (100 AU ml(-1)) in mango pulp was bactericidal and more pronounced at acidic conditions. When C. tyrobutyricum was inoculated into mango pulp with bovicin HC5, gas production was not observed. Cultures that were successively transferred in the presence of sublethal doses of bovicin HC5 did not become resistant. Conclusions: The addition of bovicin HC5 to mango pulp might be effective in preventing deterioration by spoilage bacteria. Significance and Impact of the Study: Bovicin HC5 and nisin have the potential to increase the shelf life of canned fruit pulps.