Chemical lean determination of boneless beef and lamb using a halogen moisture analyser

Abstract

Context Chemical lean (CL) is an important metric used by the Australian meat industry to describe fat content of meat product. It is a minimum meat specification included in contracts between Australian vendors of bulk packed boneless manufacturing meat and overseas or domestic buyers and can be regarded as the complement of chemically determined fat in meat (% fat, CL = 100-% fat). The microwave moisture method is commonly used for measuring CL content of meat in Australian abattoirs, relying on a relationship between CL and moisture content of boneless meat. It is regarded as a quick and easy method to use. More recently, newer methods for moisture analysis have become available which may also be suitable for CL determination, including commercial halogen moisture analysers (HMAs). HMAs use a halogen lamp as a source of infrared radiation that is absorbed by a sample, which then results in moisture loss. Aims This study aimed to compare the use of HMAs for CL determination of beef and lamb to that obtained from Soxhlet extraction technique, which is the AOAC Final Action Method for determining fat in meat and accepted as the reference method for fat determination. Additionally, the study sought to validate the use of HMAs as a method for CL determination in the Australian meat industry. Methods HMAs were used to determine the moisture content of six beef and one lamb samples, which were used to calculate the CL content. The fat content of the samples was also determined using Soxhlet fat extraction. Passing-Bablok regression and Bland-Altman plot analysis were used to identify any differences and bias between the methods, respectively. Key results Passing-Bablok regression showed that there was no difference between methods, while Bland-Altman plot analysis indicated no bias was evident between the methods. While some differences were apparent between approaches either due to using moisture as a proxy for fat/CL compared with continual solvent extraction or sample heterogeneity, sufficient agreement existed between results to lie within an acceptance criterion of 1.2 CL units. Conclusion The use of HMAs was substantiated as a method for CL determination in the Australian meat industry and has been accredited by AUS-MEAT Ltd as a method for boneless beef and lamb. Implications HMAs can be used in the Australian meat industry for CL determination and represent a relatively simpler and easier approach for this important industry metric.