Opportunities and challenges in pulsed electric field processing of dairy products

Raw and Heat-Treated Milk: From Public Health Risks to Nutritional Quality

“…that constitute the predominant microorganisms limiting the raw milk shelf-life under refrigerated conditions and also of Listeria spp., Salmonella spp., E. coli, B. cereus, S. aureus, Brucella spp., Coxiella spp. and Enterococcus [126] that can occur in raw milk.…”

Thermal properties of milk fat, xanthine oxidase, caseins and whey proteins in pulsed electric field-treated bovine whole milk

“…Thermal treatments at 63°C for 30 min and 73°C for 15 s gave the highest extent of denaturation of xanthine oxidase, 81% and 79%, respectively ( Table 2). The electric field induced changes in the native conformation of proteins are understood to be due to alteration in the dipole moment of the polypeptide chain of proteins (Buckow, Chandry, Ng, McAuley, & Swanson, 2014). The lesser extent of denaturation of xanthine oxidase after PEF treatment suggests that this technology can preserve the integrity of this protein to a greater extent compared to thermal treatments.…”

“…Xiang et al (2007) also found an increase in the ANS fluorescence intensity at an electric field strength of 22 kV cm À1 and an increasing number of pulses from 20 to 80. The observed effect in PEF-treated milk (without additional heat) could be due to the unfolding of protein molecule by Joule heating in the presence of the applied electric field (Buckow et al, 2014). In PEF treatment of milk where a preheating (55°C for 24 s) step is applied, thermal energy may also contribute to alterations in protein conformation, in addition to the electric field effects.…”

Moderate and high intensity pulsed electric fields : Effect on microbial inactivation, shelf life and quality of fruit juices

“…Reported studies showed about 3.5 log 10 inactivation of E. coli in carrot juice, pH = 6.0 (Zhong et al, 2005) and also 3.5 log 10 inactivation of L. monocytogenes in melon and watermelon juice at pH 5.8 and 5.5, respectively (Mosqueda-Melgar, Raybaudi-Massilia & Martín-Belloso, 2007), although energy input in these studies was calculated to be 1.8 − 90 times higher than used in our study. For dairy applications, electrical energy inputs of 120 − 240 kJ/kg and intermediate cooling are reported necessary for the inactivation of pathogenic micro-organisms (Buckow et al, 2014). This minimal requirement of 120 kJ/kg is in the range of that used at moderate electric field strength of E = 2.7 kJ/kg used in our study, so future research could focus on the suitability of these moderate intensity PEF conditions for dairy applications.…”

“…However, the absolute effect of a disturbance and change in electric field strength is larger for high intensity PEF than for moderate intensity electric field strength, expecting to result in a more homogeneous field distribution and higher effectivity for moderate intensity PEF than high intensity PEF. As the microbial inactivation with reduced electric field strength conditions were pH-independent, dairy products are an interesting class of products to be treated with these new conditions, possibly requiring a lower PEF energy use than the reported 120 − 240 kJ/kg for high intensity PEF (Buckow et al, 2014;Mathys et al, 2011).…”