The applicability of single end point, consumer readable Time-Temperature Indicators (TTIs) as monitors of the end of shelf life of refrigerated food products was examined. Two types of consumer TTIs, an enzymatic and a polymer based, were tested under isothermal and nonisothermal conditions. Their temperature dependence followed the Arrhenius equation (activation energy 11 to 24 kcal/mol), and except for one tag model, the response obtained under variable temperature conditions agreed well with that predicted from the Arrhenius equation. Evaluation showed satisfactory visual recognition of the end point as compared to an instrumental measurement. Consumer TTIs can be reliably used as end of shelf-life indicators for foods with a similar activation energy for deterioration.
1 International Flavors & Fragrance Co., NJ.
2Technology of Agriculture Products, Ministry of Agriculture, Lybovrissi, Greece