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CYTOTOXICITY ASSESSMENT OF BACILLUS STRAINS ISOLATED FROM STREET‐VENDED FOODS IN JOHANNESBURG, SOUTH AFRICA
Author(s) -
MOSUPYE F.M.,
LINDSAY D.,
DAMELIN L.H.,
HOLY A.
Publication year - 2002
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2002.tb00333.x
Subject(s) - bacillus cereus , bacillus licheniformis , cereus , cytotoxic t cell , cytotoxicity , microbiology and biotechnology , bacillus subtilis , bacillales , biology , chemistry , food science , bacteria , in vitro , biochemistry , genetics
Twenty‐one isolates each of Bacillus (B.) cereus, B. licheniformis and B. subtilis from street foods, collected in central Johannesburg, were randomly selected to test for cytotoxicity against McCoy 5A Mouse cells using a 3‐(4,5‐dimethylthizol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, and observation by confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM). Forty‐eight percent of B. cereus, 33% of B. licheniformis and 19% of B. subtilis strains produced cytotoxic compounds. For B. cereus strains, all supernatants exhibiting cytotoxic effects were inactivated by heat treatment at 121C for 15 min. By contrast, 24% of B. licheniformis and 10% of B. subtilis supernatants exhibited cytotoxic effects following heat treatment. CSLM and SEM showed that McCoy cells treated with cytotoxic supernatants exhibited leakage and necrosis. Presence of B. cereus, B. licheniformis and B. subtilis in street foods in high numbers may pose potetnial safety risks due to production of cytotoxic compounds.