Managing variation to produce quality in farm products.

摘要

The fundamental influence of variation on the production of quality products is reviewed. The partitioning of this variation into that which is controllable on the farm is discussed. The effectiveness of an on-farm quality assurance programme depends on the level of variation in a trait that can be controlled by farm management. A simple graphical method that can be used on the farm and is suitable for monitoring performance over time is the cusum control chart. This plots the cumulative sum of deviations, expressed as the standard deviation, from the target performance. It is designed to identify the occurrence of problems in production on the farm for which effective management action may be taken. The operation of a cusum chart for monitoring aquality assurance programme on the farm is illustrated using as an example the control of ultimate muscle pH in cattle. The cusum chart in this example is designed and operated using measurements, supplied by a meat processor, which were made on the muscle after slaughter.