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Highâpressure destruction kinetics of spoilage and pathogenic microorganisms in mango juice
- HIREMATH, NIKHIL D., RAMASWAMY, HOSAHALLI S.
- Journal of food processing and preservation 2012 v.36 no.2 pp. 113-125
- Escherichia coli O157, Leuconostoc mesenteroides, Listeria monocytogenes, Pichia membranifaciens, Zygosaccharomyces bailii, fruit crops, juices, mangoes, microorganisms, spoilage, storage time
- Highâpressure (HP) destruction kinetics of three common spoilage microorganisms, Zygosaccharomyces bailii, Pichia membranaefaciens and Leuconostoc mesenteroides, and two pathogenic microorganisms, Escherichia coli O157:H7 and Listeria monocytogenes Scott A, were evaluated in processed mango juice at pressures ranging between 250 and 550âMPa and a hold time 0â60âmin at 20â25C with generaâspecific initial counts in the 106 to 108âcfu/mL range. Microbial destruction was evaluated based on (1) an initial kill which is due to a pressure pulse (pulse effect) and (2) a subsequent semiâlogarithmic destruction during the pressure hold time. The decimal reduction times were generaâspecific and decreased with an increase in pressure. Pressure sensitivity of microbial destruction rate was evaluated by a zP value. L.âmesenteroides was found to be most resistant spoilage bacteria; yet its complete destruction was achieved by a 5âmin treatment at 400âMPa. Pathogenic E.âcoli was the most resistant of all the bacterial strains tested. A sixâlog reduction in E.âcoli O157:H7 was observed at 400âMPa when treated for 10âmin, while at 500 and 550âMPa, there were no survivors after the 1âmin treatment. HP processes were established using a 6, 8 and 10D treatment based on E.âcoli O157:H7, and counts were monitored after treatment and during subsequent storage at 20, 12 and 4C for 28âdays. Results showed that these processes were satisfactory because no growth of E.âcoli O157:H7 was observed during the entire storage time. PRACTICAL APPLICATIONS: Highâpressure (HP) processing is becoming a full commercial reality, and fruitâbased HP processed products are appearing in the marketplace at a rapidly increasing pace. Successful use of HP processing relies on established processes based on scientifically evaluated destruction kinetics of spoilage and pathogenic microorganisms, and adequately verified process safety through microbial challenge studies. This study is based on such an approach for HP processing of mango juice demonstrating the technology to be feasible if the process is properly established. The study provides the scientific kinetic base line data for establishing HP process of mango juice, which is a wellârecognized globally important exotic fruit crop.