Effect of heat treatment of milk on the physicochemical, microbiological and sensory characteristics of white cheese (Gibna bayda)

Abstract

This study was conducted to determine the effect of heat treatment of milk on the physicochemical, microbiological, and sensory characteristics of white cheese (Gibna bayda).  The cheese was made from raw warmed (45 °C) milk (T1) and heat-treated (72 °C/1 min) milk (T2) to which the starter culture (2% w/w), sodium chloride (2% w/w) and CaCl2 (0.02% w/w) were added. After manufacture, cheese was preserved at 5 °C for 45 days and subjected to physicochemical, microbiological, and sensory analysis.  The results revealed that T2 had longer coagulation time (75.5 min) and higher cheese yield (17.1 kg/100 L) compared to T1.  Fat (25.28%), moisture (55.70%), and ash (6.40%) contents were higher in T1, while protein (18.51%), total solids (47.49%) contents, and acidity (0.56%) were high in T2.  Total viable bacteria [TVB] (log10 6.64 cfu/gm), Staphylococcus aureus (log10 1.88 cfu/gm) and yeasts and moulds (log10 5.53 cfu/gm) counts were high in T1, while Escherichia coli count was log10