The range of pH in UK lamb and the influencing pre- and post-mortem factors

Abstract

Lamb with an abnormally high ultimate pH (>6.0) is considered to be of poorer quality and downgrading can be costly to the livestock industry. The UK is currently the third highest exporter of sheep meat and, with predictions of lamb production to rise 16% by 2030, it is important to ensure consistency and high standards across the industry. Despite this need, the unbalanced nature of red meat research, focusing largely on beef, has created a situation where there is a lack of understanding of the current lamb quality in the UK market. To fill the knowledge gap, this study collected and analysed the ultimate pH readings, a measure widely considered to be a good proxy for meat quality, from 2046 lamb carcases within the chillers of working Processors in the UK, during normal processing operations. Data were recorded across a year in four time periods: February-March, May-June, August-September and November-December. Additional data were also collected alongside to analyse factors influencing pH and quality: age (new season or old season), EUROP classification (conformation and fat class), cold carcase weight, transport duration, the presence or absence of pre-slaughter overnighting, and lairage duration. Results showed that the current range of pH in the UK is 4.1-7.4, with 81% of carcases falling within the ‘normal’ range of 5.5-6.0 and only 6% which could be considered ‘high’, in accordance with literature. The main influencing factors on pH were the interaction between lairage duration, overnighting and season. During warmer months, longer lairage durations saw the pH decline and during colder months, longer lairage durations led to an increase in pH. However, these differences were small in practical terms (a change in pH between 0.0002-0.002) and therefore unlikely to affect meat quality in any meaningful manner.

Date of Award	17 Jun 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Taro Takahashi (Supervisor) & Andrew Grist (Supervisor)