An investigation of the cytotoxic effect of Bacillus spp. isolated from raw milk on Vero cell cultures

Mijacevic, Z.; Bulajic, S.; Asanin, R. . Faculty of Veterinary Medicine

An investigation of the cytotoxic effect of Bacillus spp. isolated from raw milk on Vero cell cultures

1999

Mijacevic, Z. | Bulajic, S. | Asanin, R. (University of Belgrade, Belgrade (Yugoslavia). Faculty of Veterinary Medicine)

15 strains of Bacillus spp. isolated from raw milk have been screened for cytotoxicity to Vero cells. Out of this 13 were from the mesophyl group and 2 from the psychrotrophic group. All the examined strains were lecithinase positive, haemolytic and hydrolysed casein. Cytotoxicity was estimated after incubation for 1-48 h of the broth culture supernatant inoculum on Vero cells. There was no statistically significant difference in the Bacillus spp. numbers during incubation for 96 hours at 30 +- 1 deg C. A statistically significant difference in Bacillus spp. numbers (p0.05) occurred between the first and the fourth day during the incubation for 96 hours at 20 +- 1 deg C. The appearanace of a cytotoxic effect on Vero cells was found in 8 of the 15 investigated broth culture supernatants obtained after the first day of incubation of Bacillus strains at 30 +- 1 deg C in 9 after the second day and in 11 strains after the third and fourth day. After incubation of Bacillus strains in BHIG broth for 24-96 h at 20 +- 1 deg C, cytotoxicity of supernatants on Vero cells was noted in 7 out of 15 strains after the first day and in 10 strains after the second, third and the fourth days.

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