Sampling Plans to Determine the Minimum Core Temperature Reached during the Precooking of Tuna

This paper presents acceptance sampling plans that use existing statistical principles to ensure that the minimum core temperature can be used as a Critical Limit (CL) for a Critical Control Point (CCP) for precooking tuna. This strategy will ensure a 5 log10 reduction of the histamine-forming bacterium Morganella morganii and control the associated risk of histamine formation in tuna during the time needed for further processing and prior to retorting. Core temperatures of precooked tuna of different sized fish were gathered from industrial production for validation. The lower limit of the core temperature of the batch was calculated as: sample average – (3 times the standard deviation). For variable sampling plans, a sample size of 23 provided a 90% confidence level, with 99% percent acceptable, while a sample size of 35 provided a 95% confidence level, with 99% percent acceptable. Sample sizes are given for attribute sampling plans as well. The subsequent tables and sampling plans provided will allow tuna processors to develop HACCP plans to monitor CLs for a CCP for precooked tuna core temperature and allow for a significantly longer period of time in which to process tuna of any size after precooking.