Evaluation of Microbial Numbers and Physical Properties of Milk Preserved with Different Time of Pre-Heating and Pulsed Electric Fields (PEF) Exposure

Abstract

Milk production is intended for human consumption; hence preservation technology is required while maintaining the sensory and nutritional attributes. Some of technologies applied in milk are the use of pre-heating combined with pulsed electric fields (PEF) exposure. The aim of this study was to examine the effect of combination food preservation techniques using pre-heating and PEF with various conditions. The raw milk first received the pre-heating treatment at 70 ËšC, followed by PEF exposure. A completely randomized design (CDR) was applied in this research. It used two factors, namely factor I (pre-heating duration: 10, 20, and 30 minutes), and factor II (PEF exposure duration: 2, 4, and 6 minutes) with three replications, resulting in nine (9) treatments. The results reveal that there was a bacterial reduction within the range of 0.70-1.06 log CFU/mL. Besides, the increasing duration of pre-heating combined with PEF exposure decrease the values of viscosity, emulsion stability, and lightness of raw milk samples. Moreover, the most effective treatment observed in the raw milk-treated with pre-heating of 10 minutes and PEF of 2 minutes, with the level of TPC, viscosity, emulsion stability, and lightness of 1.88 log CFU/mL, 14.65 cP, and 95.65%, respectively

Pulsed electric field and pre-heating treatment effect on free fatty acid (FFA), pH, vitamin C, and organoleptic properties of milk

“…The fresh milk parameters are: negative alcohol content, 1.028 g/mL density, and 6.6 pH, which meets The Indonesian national standard (SNI) for fresh milk (SNI 01-3141-1998). The density of fresh milk used in this study was lower than in our previous study (Priyanto et al, 2022). The total plate counts (TPC) value of fresh milk we use in this study is 5.267 ± 0.017 log cfu/mL (Esfandiar et al, 2022), below the maximum value of fresh milk according to SNI, 6.00 log cfu/mL.…”

Pulsed electric field processing in the dairy sector: A review of applications, quality impact and implementation challenges

“…Priyanto et al . (2022) observed a 0.70–1.06‐log reduction of total bacterial count in raw whole milk treated with PEF (field strength = 15 kV cm −1 for 2,4 and 6 min, pulse width = 66 μs, pre‐heating = 70 °C, for 10–30 min hold). Putranto et al .…”

“…Overall, PEF is an efficient technique to significantly reduce the bacterial count in dairy products but bacterial spores reduction efficiency was comparatively lower. Some authors have successfully achieved a 5‐log reduction of targeted bacteria in milk (without pre‐heating) which is a requirement of pasteurisation (Al‐Hilphy et al ., 2021, Delso et al ., 2023) while others reported lower log reduction (even when PEF was accompanied with pre‐heating) (Sharma et al ., 2018; Priyanto et al ., 2022). This demonstrated the need to choose optimum processing parameters to achieve the maximum microbial efficiency.…”

“…Priyanto et al . (2022) reported that PEF treatment (field strength = 15 kV cm −1 , pulse width = 66 μs, pre‐heating = 70 °C) induced a substantial drop in the lightness value of raw whole milk when the treatment time increased from 2 to 6 min and pre‐heating time increased from 10 to 30 min. McAuley et al .…”