High pressure processing for microbial inactivation and shelf-life extension of fructo-oligosaccharide-fortified malt beverages

• Optimal germination period for SMG1 barley was day 8. • At 600 MPa, 6 min and 24 °C, HPP reduced Escherichia coli K12 and L. innocua > 5 log CFU/mL. • HPP prolonged shelf-life of malt beverage to at least 77 days under 8 °C. • HPP retained overall qualities of malt beverage superior to heat treatment. This study evaluated the optimal high pressure processing (HPP) condition for microbial inactivation in prebiotic-fortified malt beverages and product quality during storage. The malting duration for barley variety Samoeng 1 cultivated in Thailand was optimized at day 8 of germination. The optimized HPP condition using response surface methodology was pressure 600 MPa, holding time 6 min, and initial temperature 24 °C which reduced Escherichia coli K12 and Listeria innocua to <5 log CFU/mL meeting USFDA standards. Pressure significantly affected HPP efficiency ( p < 0.05) against both bacteria. HPP reduced beverage total plate and yeast and mold counts to below detection levels compared with conventional heat treatment (85 °C, 10 min), with a shelf-life of at least 77 days under a temperature of 8 °C while retaining physicochemical properties and sensory qualities similar to the untreated sample and superior to heat-treatment.