title: Occurrence and significance of Bacillus thuringiensis on wine grapes.
abstract: Wine grapes harvested at different stages during cultivation from several vineyards in New South Wales, Australia, harboured Bacillus thuringiensis at viable populations of 10(2)-10(6) cfu/g. Commercial preparations of B. thuringiensis had been sprayed onto the grapes as a biological insecticide. B. thuringiensis (10(1)-10(3) cfu/ml) was isolated from grape juice and fermenting grape juice in a commercial winery. Although B. thuringiensis remained viable when inoculated at 10(3)-10(4) cfu/ml into grape juice and wine (pH 3.0-6.0), it did not grow. Using in vitro agar culture assays, B. thuringiensis inhibited several grape-associated yeasts and bacteria as well as various species of fungi associated with grape spoilage and ochratoxin A production. B. thuringiensis did not inhibit Saccharomyces cerevisiae in agar culture or during alcoholic fermentation of grape juice. B. thuringiensis inhibited the malolactic bacterium, Oenococcus oeni, in agar culture but not during mixed cultures in a liquid medium.
authors.affiliation: Food Science and Technology, School of Chemical Sciences, The University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Sungsook
authors.initials: S
authors.lastname: Bae
authors.forename: Graham H
authors.initials: GH
authors.lastname: Fleet
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Heard
mesh_terms: D000898:Antibiosis; D001413:Bacillus thuringiensis / Q000502:physiology*; D001419:Bacteria / Q000254:growth & development*; D015169:Colony Count, Microbial; D005516:Food Microbiology; D007306:Insecticides; D008826:Microbial Sensitivity Tests; D027843:Vitis / Q000382:microbiology*; D014920:Wine / Q000382:microbiology; D015003:Yeasts / Q000254:growth & development*
chemical_list: D007306:Insecticides