Mathematical modeling and microbiological verification of ohmic heating of a multicomponent mixture of particles in a continuous flow ohmic heater system with electric field parallel to flow.
To accomplish continuous flow ohmic heating of a low-acid food product, sufficient heat treatment needs to be delivered to the slowest-heating particle at the outlet of the holding section. This research was aimed at developing mathematical models for sterilization of a multicomponent food in a pilot-scale ohmic heater with electric-field-oriented parallel to the flow and validating microbial inactivation by inoculated particle methods. The model involved 2 sets of simulations, one for determination of fluid temperatures, and a second for evaluating the worst-case scenario. A residence time distribution study was conducted using radio frequency identification methodology to determine the residence time of the fastest-moving particle from a sample of at least 300 particles. Thermal verification of the mathematical model showed good agreement between calculated and experimental fluid temperatures (P > 0.05) at heater and holding tube exits, with a maximum error of 0.6 °C. To achieve a specified target lethal effect at the cold spot of the slowest-heating particle, the length of holding tube required was predicted to be 22 m for a 139.6 °C process temperature with volumetric flow rate of 1.0 × 10(-4) m3/s and 0.05 m in diameter. To verify the model, a microbiological validation test was conducted using at least 299 chicken-alginate particles inoculated with Clostridium sporogenes spores per run. The inoculated pack study indicated the absence of viable microorganisms at the target treatment and its presence for a subtarget treatment, thereby verifying model predictions.
Dept. of Food Science and Technology, Kasetsart Univ., Thailand.
Pitiya
P
Kamonpatana
Hussein M H
HM
Mohamed
Mykola
M
Shynkaryk
Brian
B
Heskitt
Ahmed E
AE
Yousef
Sudhir K
SK
Sastry
D000464:Alginates / Q000737:chemistry; D000818:Animals; D002645:Chickens; D003013:Clostridium / Q000254:growth & development / Q000302:isolation & purification; D004560:Electricity; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006358:Hot Temperature; D008460:Meat / Q000032:analysis / Q000382:microbiology; D008962:Models, Theoretical; D010865:Pilot Projects; D013242:Sterilization / Q000379:methods*
D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid
Clostridium sporogenes; Ohmic heating; mathematical model; multicomponent mixture; verification