Batch accuracy of on-line fat determination.

A new method for determination of the fat content of large meat batches without sampling is presented. It is based on dual-energy X-ray (DXR) scanning of meat trimmings prior to mixing, in order to determine the exact fat content of the resulting meat batch. Twenty-seven samples of three types of pork trimmings with a fat content ranging from 24 to 63% were collected and combined into batch sizes of 27-241 kg. At small batch sizes (27 kg) the nature of the measurement error is mainly random, resulting in a prediction error (root mean square error of prediction) of 0.57% against the reference method. At a batch size of 241 kg the error was reduced to 0.34%. The DXR method determines the fat content of all meat in a batch without any sampling required, thus reducing the sampling error to a minimum. This is essential, as the results show that the sampling error is large: when 27-kg samples were homogenized and measured by the reference method, the standard deviation of high-fat samples was 4.7%.