Ohmic heating could really be a new way to process sheep milk this century?

Ohmic heating (OH) is a technique considered as a potential fluid food processing technology, due to rapidly and uniformly food material heating, requiring less energy as compared to conventional heating. The electric fields generated by OH affects moisture content, starch gelatinization, by applying different frequencies and voltage of food material and inactivation of food borne contamination microorganisms and pathogens. Process sheep milk by OH (40, 70 and 100 V) and conventional heating (CH), comparing analyze microbiology and costs effect data.
Methodology: Sheep milk processing and OH parameters calculations were performed accordingly to Pires et al. (2020) and microbiological analyzes followed Balthazar et al. (2018). It was observed the electric current was increased over time when applied a constant voltage between the electrodes immersed in milk expressed a variation on milk conductivity which consequently rose as the temperature. Thus it is possible to infer that OH40V showed higher electrical conductivity over temperature due to longer time (98 min) ohmic heating equipment was switched on to increase the milk temperature until pasteurization standard at mild voltage. Powerful voltages (OH70V and OH100V) decreased the time for milk achieves pasteurization temperature significantly (p < 0.05) for moderate (17 min) and high voltage (9 min). The energetic consumption were calculated by electrical energy spent during processing, while conventional heating (CH) was obtained by liquefied petroleum gas (LPG) consumed during milk pasteurization in water bath stainless steel container. Electrical energy or LPG consumption for OH40V, OH70V, OH100V and CH processing were 307 KJ, 146 KJ, 139 KJ, 515 KJ, respectively. The fastest heating process was CH in seven minutes, followed by OH100V, OH70V and OH40V. Surprisingly, OH processing consumed 27% (OH100V), 28.4% (OH70V) and 59.6 % (OH40V) of energy compared to CH. Accordingly with microbiological analyses OH, as well as CH maintained bacterial counts within legislation parameters. Authors verified that OH is eco-friendly and could be applied by any available AC alternate power source. However, authors warn that present results were obtained at a laboratorial scale and more studies should be developed for milk processed by OH equipments in industrial scale to compare to plate heat exchangers.