| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 102 === Temperature control is important for perishable products with short shelf life. Time temperature indicators (TTIs) are used as cost-effective devices to monitor the effect of temperature history on food quality. This study aims to develop a microbial TTI prototype to monitor grouper fillets quality change by using both total aerobic plate count and volatile basic nitrogen as quality indicators and evaluate the applicability of the TTIs as shelf life monitors under real life conditions. Our design system considers following factors: selection of specific spoilage organism, selection of chemical chromatic indicators and selection of inoculum level of bacteria. Results indicated Lactobacillus sakei is the major spoilage bacteria for vaccum package chilled grouper fillets. Chlorophenol red at 0.1 mg/ml is used as chemical indicator. 3 log cfu/ml is the inoculum level. Under such condition, the system successfully shows the color change occurs when ΔE is 20 and pH is 5.8. The activation energy of the designed TTI is 116.8 kJ/mol, which is close to the spoilage of grouper fillets sample, indicatedly volatile basic nitrogen. In addition, quality of grouper fillets are divided into three grades according to color changes of TTI. Overall, the findings offer a novel view of developing TTIs when using multiple quality indicators for seafood. Moreover, our results suggest that it is necessary to develop such TTIs since more than one quality indicator is important for an effective quality assurance system for seafood.
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