Prediction of heating lenght to obtain a definite F values during pasteurization of canned food

An empirical mathematical method to predict the heating length necessary to reach a desired F value during pasteurization treatments of canned food was developed. The method was based on (1) the fitting of heat penetration curve previously subdivided into three subsets of data and (2) the prediction of new heat penetration curves able to obtain the desired F value. The method was validated at laboratory and industrial scales by performing experimental tests on gherkins in vinegar, mushrooms in maize oil and semidried tomatoes in glass pots and tin cans. In all cases, the model well fitted the experimental data, obtaining r and E values lower than 0.990 and 3.66, respectively. The comparison between predicted and experimental heating times stated the accuracy of the method; in fact, at laboratory scale, the relative deviation values ranged between 0.622 and -5.644; instead, in a continuous pasteurizer tunnel, the values were lower than -3.898. PRACTICAL APPLICATIONS Pasteurization is the most important technology applied at industrial scale to reach safety of acidified canned foods. Although it is widely used and known, often the small medium enterprises are unable to optimize the process basing the definition of operative conditions on empirical information; for these reasons and with the aim to assure the safety, heating time is often overestimated, leading to several drawbacks such as the increase of the energy consumption, heat degradation and the decrease of productivity. In this way, the mathematical method developed in this work, which is a user-friendly tool to calculate with high accuracy, and on the basis of few experiments, the heating time necessary to reach the F value desired, is very important to the canned food industry.