Journal Article


C Hill
R P Ross
R Hickey
S M Morgan



microbial sensitivity tests escherichia coli o157 pharmacology listeria hydrogen peroxide isolation purification acids animals bacteriocins microbiology fermentation growth development milk

Efficient method for the detection of microbially-produced antibacterial substances from food systems. (2000)

Abstract A novel method for the isolation of microbially-derived inhibitory substances from food sources was developed. The method involves an enrichment step coupled to a killing assay which is initially carried out in multiwell plates. The technique has advantages in that large numbers of samples can be tested in parallel. The assay can be completed in less than 60 h and is more sensitive than direct plating due to the enrichment step. This novel screening approach was compared with the standard direct plating approach in an effort to identify the antimicrobial potential of a number of Kefir grains. Kefir grains were incubated in 10% reconstituted skim milk for 20 h at 32 degrees C to enable production of any potential biopreservatives. Following overnight incubation, fermentates were aliquoted into multi-well plates and a known number of indicator cells was added to each well. The fermentates were incubated for a further 20 h and counts were carried out to determine whether a reduction in indicator cell numbers had occurred. A reduction in cell-forming units indicated the presence of an inhibitory substance and these inhibitory fermentates were selected for further investigation. Using the protocol outlined, Kefir fermentates capable of inhibiting Listeria innocua DPC1770 and Escherichia coli O157:H45 were identified.
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Full list of authors on original publication

C Hill, R P Ross, R Hickey, S M Morgan

Experts in our system

Colin Hill
University College Cork
Total Publications: 351
R Paul Ross
Total Publications: 441
Rita M. Hickey
Total Publications: 24