Thermal Processing of Foods: Part II. Lethality Determination

• Published in: Food Engineering Laboratory Manual pp. 39 - 52
• Main Authors: Barbosa-Cánovas, Gustavo V., Ma, Li, Barletta, Blas
• Format: Book Chapter
• Language: English
• Published: United States CRC Press 1997; CRC Press LLC
• Edition: 1
• Subjects: Food & beverage technology; Required Processing Temperature; TDT Curve; Rt; Thermal Process; Lethal Rate; TDT; Coxiella Burnetti; Cooling Lag Factor; Surface Convective Heat Transfer Coefficient; Heating Lag Factor; Decimal Reduction Time; Clostridium Botulinum; Heat Transfer Mechanism; Heat Penetration Data; Falling Rate Stage; Required Processing Time; Heat Penetration Curves; Integrated Lethality; Microbial Inactivation; Heat Penetration; Lethality Determination; Moisture Content; Cold Point; Formula Methods
• ISBN: 9781566765411; 1566765412
• DOI: 10.1201/9780203755662-5

This chapter focuses on the problem of relating the lethal effect on the microorganism of interest when processing a food product. To understand the kinetics of microbial or enzymatic inactivation, some background is provided. The purpose of the laboratory exercise is to understand and evaluate a thermal process in a food product heated by conduction and convection. When the heat transfer mechanism is dominated by convection in a thermal process that is liquid or highly viscous, there is movement of the product inside the container due to natural convection and buoyancy forces. When the heat transfer mechanism is dominated by conduction, there is no product movement inside the can. The solution to the problem of finding an integrated lethality for the whole can is quite complex. A low-acid food is preferred because it has great commercial importance in a sterilization process due to the possible presence of Clostridium botulinum. The chapter illustrates some examples with solutions for lethality determination.