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This project evaluated the antimicrobial activity of whey samples and its potential as a new sanitising agent. Whey samples produced during the manufacture of various cheese types were tested. Different thermal treatments (65°C for 10, 20 and 30 minutes, 72°C for 15 sec and 121°C for 15 minutes) were applied to the whey samples. The impact of the heat treatment on mesophilic, psychrotrophic and lactic acid bacteria, yeast and moulds were monitored. The physio-chemical properties (pH, water activity, moisture content, ash content, soluble solids and turbidity), proximate analysis (protein content using the Bradford assay and peptide pattern using SDS-PAGE) of the various samples were determined. Their antimicrobial activity against Escherichia coli ATCC 25922 (microtiter plate assay) was investigated. The application of heat treatment (65°C for 20 minutes) after dialysis reduced initial microbiological load in all whey samples. Blue cheese whey sample non dialysed (ND) had the highest protein content (338.01 ± 3.79 mg/100ml) and had the highest percentage inhibition (93.29 ± 5.25%) against E. coli which is equal to the activity of sodium benzoate (60 mg/ml) a popular food preservative.
Mohsen Pour, S. (2014) The Antimicrobial Activity of Whey Permeate (Against Escherichia Coli ATCC 25922), Dissertation, PgDip(Res), Dublin Institute of Technology.