Study of Shelf Life of Pasteurized Tempe Vacuum Packed with HDPE and Aluminium Foil Packaging

Abstract

Tempe is very perishable food at room temperature. Several techniques used to process tempe for its preservation have been developed. These processing techniques include drying, frying, and canning have been used to achieve long shelf life of tempe, with the significant loss of tempe’s freshness. The objective of this research was to evaluate the effect of pasteurization process, as a milder heat treatment, in combination with vacuum packaging on extending shelf life of tempe. Using a target microbe of nonproteolytic C. botulinum with z value of 7.2 oC and D85 of 0.28 minutes, the extent of pasteurization process was based on the heat penetration data and calculated as Pv = P85 (z=7.2). Our result indicated that 6D reduction of C. botulinum was easily achieved at all temperatures of pasteurization. Futhermore, from several combinations of time and temperature studied, the optimum pasteurization value resulted in maximum shelf life of pasteurized tempe. The optimum pasteurization values of tempe vacuum packed in HDPE and stored at 5, 15, and 20 oC were 35.05, 35.36 and 33.30 minutes. The associated maximum shelf life of the tempe were 24, 16, and 13 days. For tempe vacuum packed in aluminium foil and stored at 5, 15, and 20 oC, the optimum pasteurization values were 37.04, 35.44, and. 42.47 minutes. These optimum pasteurization values resulted in shelf life of 25, 17, and 12 days. Therefore, the longest shelf life of 25 days was obtained from P85 (z=7.2) of 37 minutes by using aluminium foil packaging and stored at 5 oC. The anomaly observations, in which the shelf life was not proportional to the pasteurization value, was interesting and thought to be associated with complex microbiological nature of tempe as fermented soyfood.