An assessment of methods of sampling bulk grain

Abstract

Removal and examination of samples of grain is the most widely used method of measuring quality parameters. However, there are few research data to support methods currently used or to quantify errors that may occur. Many variables, such as the equipment, operator or the type of grain storage, may affect the make-up of samples and, therefore, the results obtained.

A series of experiments was done to determine the effectiveness of various sampling methods at detecting insects in bulk grain and to assess the influence of these different methods on the results of quality measurements. It proved almost impossible to detect insects at infestation levels below about 5/kg using commercial rates of sampling. There were large errors in predicting some quality parameters, such as total impurities and broken grains, but quality prediction was not affected by sampling equipment. Statistical analysis confirmed that the accuracy of prediction was related to both the number of samples from a single lot and the number of individual lots that were examined. The best method of assessing the quality of a bulk would appear to be pool the results from the assessment of the individual lots that go to make up the bulk.

Further work on sampling is reported as Project Report No 79 and Project Report No 118.