Comparisons of the General and Ball Formula Methods for Retort Pouch Process Calculations

ABSTRACT

Comparisons of general and formula methods were made for pouches processed under water in a still vertical retort. Changes were considered in the conventional use of the formula method. Heat penetration tests were performed using horizontally positioned pouches (3/4 inch pouch thickness). Tests on pureed product using a common brass thermocouple receptacle indicated a probability of less than 1% that errors were caused by the receptacle. Tests were then conducted using the same puree and two types of particulate products. Inclusion of the lethality portion of come-up time and the actual cooling lag factor in Ball calculations reduced the difference greater than 60% (5 min) and 18% (2 min), respectively, over the shorter general method times.