Effect of LP-system activation using externally added potassium thiocyanate, glucose oxidase, and glucose on total bacterial count and pH variability in raw buffalo milk

Abstract

Lactoperoxidase system has received high attention for raw milk preservation, because the system exerts hypothiocyanate ions to inhibit the growth of broad spectrum bacteria. The effectiveness of Lactoperoxidase system varies with LP-component concentration. LP-system was activated using different enzyme (glucose oxidase), substrate (glucose) concentrations in the presence of potassium thiocyanate at 37°C. Comparison was made by measuring extent of bacterial multiplication (SPC) and pH variation. At 37°C, for control milk, total bacterial count was around 5.057±0.057 log10 cfu/ml at 0th hour but it showed increasing effect up to 8.732±0.024 log10 cfu/ml after 5th hour.Whereas total bacterial count for LP-activated milk under varying concentrations of thiocyanate (30, 15 and 7.5 mg/l) with 2000 mg/l glucose and 400 U/l glucose oxidase was 7.239±0.239, 8.241±0.037 and 8.900±0.055 log10 cfu/ ml respectively after 9th hour at 37°C that clearly indicated the effectiveness of LP-component concentration on bacterial multiplication. pH of activated milk was continuously decreasing in milk samples with lower enzyme (glucose oxidase) substrate (glucose) concentration.