Journal Article

Application of on-pack pH indicators to monitor freshness of modified atmospheric packaged raw beef

Bhadury, Debarati, Dyson, Jennifer M, Tanner, Joanne, Tuck, Kellie L, Lin, Maoqi, Nadeem, Humayun

2024

Overview

Abstract Objectives To deveop on-pack visual indicators for the real-time monitoring of raw beef steaks in a modified atmospheric packaging (MAP). Materials and Methods Three indicators were prepared by spray deposition of a nanocellulose suspension (1.5%, in mass) with the desired concentration of the pH-sensitive indicators, either red cabbage (RC) extract, black carrot (BC) extract, or chlorophenol red (CPR). The responsiveness of the colorimetric pH indicators, assessed visually and by CIE-Lab quantitative analysis, to the freshness of raw beef steaks stored under MAP conditions at 4 °C or 20 °C, was analysed over 7 d. Results All the indicators showed a colour change for beef steak stored at 4 °C for 7 d that was noticeable with the naked eye and had a ΔE value>12. The sensitivity of the RC pH indicator was superior to that of the BC and CPR pH indicators. A study linking total microbial count (aerobic+Escherichia coli+coliform) and the quantitative colorimetric response of the indicators (ΔE) revealed a strong linear correlation. Conclusions The developed colorimetric pH indicators could be used to monitor the freshness of raw beef and as an alternative to the best-before date commonly used in pre-packaged meat. Graphical Abstract Graphical Abstract

• Publisher: Oxford University Press
• Subject: Beef / Chlorophenol / Colorimetry / E coli / Freshness / Indicators / Microorganisms / pH effects / Quantitative analysis / Real time / Spray deposition