On-package dual sensors label based on pH indicators for real-time monitoring of beef freshness

On-package dual sensors label has been constructed based on two pH indicators, and it has been applied to monitor the beef freshness. The two pH indicators used are methyl red (MR) and bromo cresol purple (BCP). The beef decay could be detected clearly and easily by the dual color indicators, where the MR change from red to yellow, while the BCP change from yellow to purple. The label responses accurately to the beef freshness, in term of its pH change due to the deterioration as shown by both color change at room and chiller temperatures. Similarly with the other parameters, such as the total volatile basic amine (TVBN), total viable count (TVC) and sensory evaluation. These levels were reached at 8 h and 7 days as the threshold of spoilage at room and chiller temperature respectively. Therefore, the label can be used as a simple and practical indicator for freshness monitoring of packaged beef.