Development of an autonomous, wireless pH and temperature sensing system for monitoring pig meat quality June Frisby a , Declan Raftery a , Joe P. Kerry b , Dermot Diamond a, * a National Centre for Sensor Research (NCSR), Dublin City University, Dublin 9, Ireland b Department of Food and Nutritional Sciences, University College Cork – National University of Ireland, Cork, Ireland Received 28 August 2004; received in revised form 28 January 2005; accepted 28 January 2005 Abstract This paper focuses on the development of a unique wireless pH and temperature monitoring system to assess pig meat quality. Pale, soft and exudative (PSE) pig meat continues to be a major problem in the pig meat industry today. The PSE condition in pork is related to a number of factors including genetics, pre-slaughter stress and insufficient chilling of pig carcasses, which cause a rapid rate of glycolysis post-mortem (<1 h). As a result the pH drops to low levels while the muscle temperature is still high. A wireless dual channel system that monitors pH and temperature simultaneously has been developed to provide pH and temperature data of the carcass during the first 24 h after slaughter. We have demonstrated that this approach can distinguish in real time, pH and tem- perature profiles that are Ônon-normalÕ, and identify carcasses that are PSE positive quickly and easily. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Wireless sensing; pH; Temperature; PSE pig meat; Food quality 1. Introduction One of the biggest challenges confronting the pork manufacturing industry today is the demand for high quality meat products. PSE pig meat is a major problem causing huge financial costs within meat processing industries. A recent study carried out in Ireland indi- cated that cooked hams manufactured from severe PSE pork had an estimated financial loss of 50% in com- parison to those manufactured from normal pork (OÕNeill, Lynch, Troy, Buckley, & Kerry, 2003). The re- sults from this study indicate that PSE muscles are diffi- cult to process into high quality products. Pre-slaughter handling, method of slaughter and chilling at the pro- cessing plant are all factors that influence pork quality (Grandin, 1994, 1997; Lynch et al., 1998; Rosenvold & Andersen, 1997; Van der Wal, Engel, & Hulsegge, 1997). It is difficult to establish standard procedures for measuring the quality of pork within the industry as pork quality characteristics change dramatically with time. In recent years many novel techniques have been assessed for their ability to measure the quality of meat in the early post-mortem period (Forrest, 1998; Van Laack, Kauffman, & Polidori, 1998). These include mea- surement of muscle electrical properties (Byrne, Troy, & Buckley, 2001) and reflectance using fibre optic probes (Geesink et al., 2003). Muscle has certain electrical char- acteristics such as impedance and conductivity, which change with time post-mortem (Byrne et al., 2001). If these complex electrical changes are correlated with muscle pH decline, they may be of value in the assess- ment of meat quality. However at the critical time (45 min post-mortem), neither optical nor electrical methods are yet sufficiently reliable for accurate diagno- sis of PSE (Swatland, 1996). pH has been repeatedly shown to be the best among the known predictors of 0309-1740/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2005.01.023 * Corresponding author. Tel.: +353 1 704 5404; fax: +353 1 700 8021. E-mail addresses: june.frisby@dcu.ie (J. Frisby), dermot.dia- mond@dcu.ie (D. Diamond). www.elsevier.com/locate/meatsci Meat Science 70 (2005) 329–336 MEAT SCIENCE