Pengembangan sistem pasteurisasi berbasis kombinasi Ultraviolet (UV) dan Medan Pulsa Listrik Tegangan Tinggi (HPEF) untuk susu kambing

Abstract

Some efforts have been addressed in order to fulfill the demand of consumers towards goat’s milk products to produce a high quality and effective process for inactivating pathogenic bacteria without damaging the physical, chemical properties of milk, has minimal affects which causes quality and nutritional degradation and reduce, sensory acceptance value. One of alternative method is combination of the ultraviolet (UV) and high pulsed electric field (HPEF). The UV pasteurization instrument uses three reactors constructed in series system at UV-C 10 W and 253.7 nm wavelength with specification 1.80 J/cm2 dose per reactor. The specification of HPEF instrument is 31.67 kV/cm, 0.11 mA, oscilatory and 7.0 pulses for high electric field voltage, electrical current, pulse form and number of pulses, respectively with goat’s milk rate at 4.32 ± 0.71 cc/second. The material for the experiment was fresh goat’s milk sterilized using autoclave at 115oC for 3 minutes and ready for recontamination using Salmonella Typhimurium ATCC 14028, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. The bacteria were obtained from Integrated Laboratory of Faculty Animal Science, Bogor Agricultural University which had been grown in 105 cfu/ml concentration. The statistical analysis was conducted using Complete Randomized Design. Observed variables were total bacteria, pathogenic bacteria (S. Typhimurium, E. coli dan S. aureus) and physical, chemical properties before and after treatment. The result showed that the inactivation reduction rate using series system of UV series-HPEF at 5.50, 7.00 and 10.00 pulses were 70.00%; 89.49% and 85.67% respectively. The statistical analysis showed that the physical, chemical properties among treatments were insignificantly different (P>0.05). Inactivation rate was 0.52; 0.98 and 0.84 log cycle or 11.78; 22.04 and 19.01 log cfu/ml/hour, respectively; D value was 0.09; 0.05 and 0.05 hour, respectively. Whereas bacteria pathogen inactivation rate of Salmonella Typhimurium ATCC 14028, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 was 0.28; 0.07 and 0.19 log cycle, respectively. The observation of cell damage using SEM (Scanning Electron Microscopy) showed that Salmonella Typhimurium ATCC 14028 and Staphylococcus aureus ATCC 25923 cell had formation changes.