Title: Inactivation of E. coli K12 in buffered peptone water and apple cider by pilot-plant scale supercritical carbon dioxide system Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 7, 2008
Publication Date: June 28, 2008
Citation: Yuk,H-Gyun,Geveke, D.,Zhang,H. 2008. Inactivation of E.coli K12 in buffered peptone water and apple cider by pilot-lant scale supercritical carbon dioxide system [abstract].Institute of Food Technologists (IFT) Annual Meeting.New Orelaans. LA. p.1. Technical Abstract: There is increasing interest in non-thermal processing to inactivate foodborne pathogens and background microflora in juice products. Non-thermal pasteurization ensures safety and may offer better quality products than thermal pasteurization. Of non-thermal technologies, use of supercritical carbon dioxide (SCCO2) is promising in that carbon dioxide (CO2) is non-toxic, non-reactive, non-flammable, inexpensive, and environmentally safe. Data is lacking on the ability of a continuous SCCO2 system to inactivate E. coli K12 in buffered peptone water (BPW) and apple cider. Autoclaved stock BPW (100g/L) diluted in distilled water to 0.1% concentration and pasteurized apple cider without preservatives were used for this study. BPW and apple cider inoculated with E. coli K12 were processed using a SCCO2 system at a CO2 concentration range of 0 – 9.4% (g CO2/100 g product), hold temperatures of 34, 38, and 42C, a system pressure of greater than 7.6 MPa, and a flow rate of 1 L/min. Higher CO2 concentration and temperature enhanced microbial reduction. A 6-log reduction was obtained at 8.1% and 42C for BPW and a 7-log reduction was achieved at 6.8% and 42C for apple cider. To achieve a 5-log reduction of E. coli K12 in BPW, minimum CO2 concentrations of 9.6, 5.9, and 4.8% were needed at 34, 38, and 42C, respectively. For apple cider, minimum concentrations of CO2 for inactivating 5-log unit were 6.2% at 34C, 5.8% at 38C, and 4.1% at 42C. A central composite design indicated that factors significantly (P < 0.05) affecting the inactivation of E. coli K12 were temperatures for BPW and CO2 concentrations for apple cider. This study showed that the pilot-plant scale SCCO2 system could be applicable for non-thermal pasteurization of apple cider.