REPORT: wheat testing to meet world standards Research shows areas for improvement by Bernie Reppel

Grower-supported research has yielded a five-year plan to take Australia's grains exporting industry to world leadership in quality testing (see story p4).

A new national quality testing centre for grains was unveiled by the GRDC Board following a review commissioned by the Corporation and follow-up research on ways to further improve wheat quality testing at receival depots in Australia.

Last year the Queensland Graingrowers Association (QGGA) told a GRDC review of testing procedures that a 0.1 per cent error in testing a 60 tonne load of wheat at delivery could cost a grower as much as $1,200.

QGGA said this could happen when the Australian Wheat Board's (AWB's) price differentials were more than $20/t around a 0.1 per cent protein increment and "when the testing levels cannot deliver the necessary level of accuracy".

Accuracy research

Because of these and other concerns, the GRDC supported a research project on accuracy and consistency of wheat quality testing by Brian Osborne, of the Bread Research Institute, and John Ronalds, of CSIRO's Grain Quality Research Laboratory.

The two scientists inspected 15 receival stations in five States, as well as visiting district laboratories and the head offices of bulk handling authorities (BHAs). The aim was a critical review of current procedures.

The review found that all BHAs had made substantial investments in equipment and significant improvements since a previous review in 1989. But further improvement was possible.

Aiming for best practice

Recommendations made by Dr Osborne and Mr Ronalds included:

  • an immediate end to the use of hand grain probes with ports which opensimultaneously, in favour of probes with ports opening sequentially from the bottom;
  • urgent and thorough evaluation for bias and consistency of simple core samplers based on industrial vacuum cleaners and — if feasible — parallel evaluation of the various types of remotely controlled truck samplers; and
  • mechanical mixing and subsampling equipment to be used in place of existing hand procedures.

The review did not question the accuracy and consistency of near infrared reflectance (NIR) and transmittance (NIT) which it said were the only technologies rapid enough for load by load protein testing while allowing integration with other quality tests.

However accuracy of results across different loads and their consistency across different receival stations needed to be addressed.

Part of the problem appears to be the consistency of NIR/NIT calibration against a chemical reference standard. Two international methods are used in Australia which don't give the same results on the same sample.

"Current practice in all states is to calibrate the NIR/NIT equipment prior to the commencement of harvest, then to update the calibrations continually, (against reference standard) results on check samples taken from each receival station," Dr Osborne and Mr Ronalds reported.

"The risk of payments becoming distorted by systematic errors in protein test results is greatest at the beginning of the season, when relatively large adjustments are most likely to be made to calibrations, especially as such adjustments are made on a station by station basis.

"The practice in some States of using different calibrations for different subregions could result in discrepancies in readings if the same sample is submitted for testing at neighbouring receiving stations.

"Such discrepancies experienced by some growers who choose to 'shop around' appear to be a major cause of the perceived lack of consistency in results.These potential problems could be avoided by deriving for each state a single calibration for protein which does not require major adjustment each season."

Improving protein tests

The researchers recommended two areas for improving the accuracy of protein tests: the earliest possible introduction and the networking of whole-grain instruments (rather than ground grain analysis) throughout the grain receival system; and, research towards the development of stable, robust calibrations that are unaffected by weather damage and do not require adjustment each season.

The Grain Industries Centre for NIR has been established at the Bread Research Institute of Australia in Sydney to catapult this country into world leadership in wheat quality testing.

The $2 million, five-year investment by growers through the GRDC is in response to a review and research on receival testing throughout Australia (see story above). The Centre's national coordinator is Brian Osborne who jointly conducted the research and is rated an international expert on NIR technology.

The Centre will help Australia develop world best objective grain measurements for many quality specifications beyond protein and moisture, the current tests. Topping the list for new quality measures is grain hardness, extensibility of dough, quality of feed, barley malting quality and specifications for crops like oilseeds and pulses.

NIR has the advantage of being fast, accurate and cheap and requires very little grain. Reportedly, none of Australia's international competitors presently is able to measure these quality characteristics routinely to satisfy discerning markets.

Region North