Document Type

Dissertation

Rights

This item is available under a Creative Commons License for non-commercial use only

Publication Details

Successfully submitted to Dublin Institute of Technology, Ireland, in fulfilment of the requirement for the award of the degree of PgDip by research

Abstract

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.

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