Inactivation of naturally occurring microbiota in cucumber juice by pressure treatment

• Published in: International journal of food microbiology Vol. 174; pp. 12 - 18
• Main Authors: Zhao, Liang, Wang, Yongtao, Wang, Siyuan, Li, Hui, Huang, Wenshu, Liao, Xiaojun
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 17.03.2014; Elsevier
• Subjects: Anti-Infective Agents - pharmacology; Beverages - microbiology; Biological and medical sciences; Colony Count, Microbial; Cucumber juice; Decompression time; Food industries; Food microbiology; Food Microbiology - methods; Fundamental and applied biological sciences. Psychology; Fungi - drug effects; Fungi - physiology; High hydrostatic pressure; Homogenization; Hydrostatic Pressure; Microbial Viability; Microbiota - physiology; Modeling; Nisin; Nisin - pharmacology; Time; Yeasts - physiology; Homogenization; Nisin; High hydrostatic pressure; Decompression time; Cucumber juice; Modeling; Microorganism interrelationships; Vegetables; Physical dressing; Bacteriocin; Microflora; Inactivation; High pressure; Hydrostatic pressure; Cucumber
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2013.12.023

The inactivation effects of high hydrostatic pressure (HHP) (350MPa/10min, 400MPa/4min and 500MPa/2min) with homogenization (20MPa/2min), nisin (100IU/mL) and decompression time (<3s and 7–8s) on naturally occurring microbiota in cucumber juice were investigated. Initial concentration of yeasts and molds (Y&M) was 5.6×103–2.4×104CFU/mL, and total plate count (TPC) was 1.0×105–3.5×105CFU/mL. Y&M were inactivated below the detection level (≤10CFU/mL) in all cases. The reduction of TPC in non-homogenized cucumber juice (NHCJ) was 2.5–3.0 log cycles, which was significantly higher than 1.0 log cycle in homogenized cucumber juice. The combination of nisin with HHP had a synergistic effect on the inactivation of TPC. The reduction of TPC in NHCJ with a decompression time of <3s was approximately 4.5 log cycles, which was significantly higher than a decompression time of 7–8s. Five non-linear models including the biphasic, Weibull, modified Gompertz, log-logistic and Baranyi models were fitted to TPC inactivation curves for the NHCJ at 300, 350 and 400MPa for 2–15min and 500MPa for 2–8min at a decompression time of <3s. The biphasic model provided the best fit for the data. •Homogenization played an unfavorable role in the inactivation of TPC by HHP.•Nisin had a synergistic effect on the inactivation of TPC with HHP.•A decreased decompression time with HHP enhanced the inactivation effect of TPC.•The biphasic model provided the best fit with the data to describe the effects of HHP on TPC.