Patent ID: 7430982

Claim:
A TTI indicator device comprising: a substrate layer selected from packaging materials comprising paper, cardboard, plastic foil, metal or glass; agent A and agent B, a diffusion layer comprising film-forming substance(s) selected from carboxymethyl cellulose, micro-crystalline cellulose, methyl cellulose, hydroxypropylmethyl cellulose, starches, corn protein, soy protein, casein, glutein, cyclodextrins, cithosan, lecithin, phospholipide, hydro-gels, sol-gels, gum Arabic and agarose dissolved in a solvent or mixture of solvents, agent A being a pH-indicator and agent B being an organic acid selected from citric acid, tartaric acid, lactic acid, acetic acid and formic acid, and a) the agent A and agent B being adjacent to each other but not in direct contact with each other and the diffusion layer being on the agent A and agent B, or b) the agent A being on top of agent B and the diffusion layer being on the agent A, or the agent B being on top of the agent A and the diffusion layer being on the agent B; or c) a blend of the agents A and B being on the substrate layer and the diffusion layer being on the blend.