inspecting grain wheat for defects and impurities · hazards and must not be inhaled. ergot the...

Inspecting grainfor defects and impurities

For best practice grainsampling and storage forcereals and oilseeds,consult the Grain samplingguide and the Grain storageguide, or go to:

cereals.ahdb.org.uk/grainstorage

Physical damage

Smell Diseases

PestsScreenings

Weed seedsBrome

Black-grass

Couch

Wild oats

Bindweed

Cleavers

Brassica

Unwanted non- cereal matter (eg chaff, straw, stones) that has no value to the miller andmust be removed before milling. Stones can damage machinery; metal objects maycause sparks.

To check for insects, the whole of a laboratory sample should be inspected and sieved(typically using a 2mm mesh) and the material passing through the mesh examinedthoroughly. This is especially important for grain going into storage.

25mm

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20 –30mm

7–14mm

6mm

3–4.5mm

2–5mm

2–3.5mm

Insect damageThis example shows weevil damage. Eggsare laid within the grain. Endosperm is eatenby the larvae inside the kernels.Evidence of insects indicates poor storageand possibly local hot spots.The presence of live insect pests isunacceptable to processors.

Orange blossom midgeMidges infest crops at flowering, laying eggsin empty florets.The larvae attack immature grain, pierce thebran and inject enzymes into the grain. Thiscan lead to water ingress and low HagbergFalling Numbers.Black areas indicate additional fungalinfection.

Rodent droppingsRodents directly damage grain and carryinfection.Rodents urinate on grain, posing a foodsafety risk. Contaminated grain is unacceptable.

FusariumPink moulds indicate possible Fusariuminfection. Some Fusarium fungi can producemycotoxins that are toxic to humans andanimals. Permitted mycotoxin levels aregoverned by legislation or tradingspecifications.

Mouldy grainsDull looking, weathered grains indicate poorharvest conditions and may impair quality,eg wholemeal colour.Dullness may be due to spores or mouldswhich are unacceptable to all users due tothe risk of mycotoxin formation.

Spores present possible healthhazards and must not be inhaled.

ErgotThe fruiting body of the fungus Clavicepspurpurea affects grasses as well as rye,wheat and barley.The inside of an ergot is grey/white, whichdistinguishes it from rodent droppings.Ergot is toxic to humans and animals and so isunnacceptable to any processor.

Bunt (Tilletia tritici)Fragile grains, dark in colour. Part of the grainmay have eroded.Surface cracks may reveal black powderyspores within the endosperm. Bunt ballsoccur occasionally and spores give grains adull look.Infected grain has a pungent fishy smell,making it unacceptable for cereal products.

BlackpointAs a response to infection the plant produceschemicals in the bran which vary from brown toblack over the germ area. Blackpoint is often associated with Alternariainfection but this is not the only cause. Somevarieties are more prone to blackpoint thanothers.Dark bran specks in flour can affect flour quality.

Broken grainsExposed endosperm, usually due toaggressive handling, provides potential sitesfor mould infections.Broken grains are removed during thecleaning process and hence milling potentialis reduced due to a lower yield of clean,white flour from each tonne purchased.

Sprouted grainsGerminated grains, caused by wet harvestconditions, will have very high levels ofalpha-amylase. Even a few in a bulk canreduce Hagberg Falling Number tounacceptable values, resulting in rejection ofmilling wheat.

Lost embryosEmbryos may be damaged mechanically orby mites (as shown) or insects.Damage by mites or insects may indicatepoor storage.

Burnt grains/heat damageHeat damage arises from localised ‘hotspots’ or excessive temperatures duringdrying.Grains can range in colour from bronze todark brown (charred).Such wheat is unacceptable. Over-dried grainwill have irreversibly damaged gluten.

Large screeningsStraw, beans, unthreshed grain, sticks,stones, etc.

Small screeningsBroken grains, shrivelled grains, chaff, weedseeds and small straw pieces.

Mud and stonesMud balls are a particular problem during wetharvests.Stones can be picked up during combining,particularly when harvesting conditions aredifficult.

Dust, chaff and fine soilIf dust is visible, do not smell it asgrain dust can be harmful if inhaledand can cause respiratory problems.

When inspecting grain, note any unusual smells. A sweet or minty smell indicatesmites; musty and fishy smells indicate moulds; chemical smells, eg cleaning fluidsand diesel, can also occur. If the grain is visibly mouldy or dusty, do not smell it. Moulds and grain dust can be harmful and cause respiratory problems.

While the Agriculture and Horticulture Development Board seeks to ensure that the informationcontained within this document is accurate at the time of printing, no warranty is given in respectthereof and, to the maximum extent permitted by law, the Agriculture and HorticultureDevelopment Board accepts no liability for loss, damage or injury howsoever caused (includingthat caused by negligence) or suffered directly or indirectly in relation to information and opinionscontained in or omitted from this document.

Reference herein to trade names and proprietary products without stating that they are protecteddoes not imply that they may be regarded as unprotected and thus free for general use. Noendorsement of named products is intended, nor is any criticism implied of other alternative, butunnamed products.

AHDB Cereals & Oilseeds is a part of the Agriculture and Horticulture Development Board (AHDB).

WHEAT

cereals.ahdb.org.uk © Agriculture and Horticulture Development Board 2016. All rights reserved.

For additional copies of this poster, contactcereals.publications@ahdb.org.ukor 0845 245 0009

For best practice grainsampling and storage forcereals and oilseeds,consult the Grainsampling guide and theGrain storage guide, orgo to:

cereals.ahdb.org.uk/grainstorage

BARLEY

cereals.ahdb.org.uk © Agriculture and Horticulture Development Board 2016. All rights reserved.

Physical damage

Diseases

Pests

Weed seedsBrome

Black-grass

Couch

Wild oats

Bindweed

Cleavers

Brassica

25mm

20–30mm

7–14mm

6mm

3–4.5mm

2–5mm

2–3.5mm

FusariumPink moulds indicate possible Fusariuminfection.Some Fusarium fungi can produce mycotoxinsthat are toxic to humans and animals.Permitted mycotoxin levels are governed bylegislation or trading specifications. May cause gushing of bottled beers.

Mouldy grainsMay result from adverse growing, harvest orstorage conditions. Quality may be impaired.Dullness may be due to spores or moulds,which are unacceptable to all users due tothe risk of mycotoxin forming.

Spores present possible healthhazards and must not be inhaled.

ErgotThe fruiting body of the fungus Clavicepspurpurea, which affects grasses as well asrye, wheat and barley.The inside of an ergot is grey/white, whichdistinguishes it from rodent droppings.Ergot is toxic to humans and animals and sois unnacceptable to any processor.

Insect damageThis example shows weevil damage. Eggsare laid within the grain and the endospermis eaten by the larvae.Evidence of insects indicates poor storageand possibly local hot spots.Severe infestations (as in this example) areunacceptable to processors.

Rodent droppingsRodents directly damage grain and carryinfection.Rodents urinate on grain, posing a foodsafety risk.Contaminated grain is unacceptable.

Broken grainsExposed endosperm, usually due toaggressive handling, provides potential sitesfor mould infections.Can cause processing problems. Theseinclude excessive water uptake and mushysteep with starch leaching into steep water.

Burnt grains/heat damageHeat damage arises from localised ‘hot spots’or excessive temperatures during drying.Grains can range in colour from bronze todark brown (charred).Over-dried grains are unlikely to germinateand may affect beer or malt flavour.

SplittingCracks through outer grain tissues may arisefrom excessive expansion or mechanicalweakness. Splits often occur along the ventralcrease but can also occur on the side (lateral)and back (dorsal). Exposed endosperm issusceptible to mould attack.Processing problems include excessive wateruptake and mushy steep with starch leachinginto steep water.

SkinningA separation and loss of lemma and palea(husk). Causes include developmentalfactors, weather conditions, rough harvestand post-harvest handling. May lead tofiltration problems due to loss of husk andhence malt production efficiency is likely tobe reduced. Dust problems during handlingmay arise. More prevalent in spring varieties.

GapeA gap between husk tissues (lemma andpalea) due to poor development and/orexcessive expansion. Endosperm remainsintact. Gape – a function of variety and environment– is not necessarily a defect unlessassociated with lateral splitting.

Lost embryosCommonly caused by mechanical damage.Of no use for malting as the grain will notgerminate.

Pre-germination (light)Recognised by a swollen and raised germarea. Pre-germinated grains may not maltand hence will reduce malt yield.Pre-germinated grains can be detected bylaboratory testing.

Pre-germination (heavy)Sprouted grains with visible rootlets will notmalt and hence will reduce malt yield.

Discoloured grainDull looking, weathered grains indicate poorharvest conditions and may lead to qualityproblems.Dullness can be due to spores or moulds.

ScreeningsUnwanted non-cereal matter (eg chaff, straw, stones). Stones can damage machinery;metal objects may cause sparks.

Large screeningsStraw, beans, unthreshed grain, sticks,stones, etc.

Small screeningsBroken grains, shrivelled grains, chaff, weedseeds and small straw pieces.

Mud and stonesMud balls are a particular problem during wetharvests.Stones can be picked up during combining,particularly when harvesting conditions aredifficult.

Dust, chaff and fine soilIf dust is visible, do not smell it asgrain dust can be harmful if inhaledand can cause respiratoryproblems.

Inspecting grainfor defects and impurities

To check for insects, the whole of a laboratory sample should be visibly inspected andsieved (typically using a 2mm mesh) and the grain passing through the mesh examined.This is especially important for grain going into storage.

For additional copiesof this poster, contactcereals.publications@ahdb.org.ukor 0845 245 0009

SmellWhen inspecting grain, note any unusual smells. A sweet or minty smell indicatesmites; musty and fishy smells indicate moulds; chemical smells, eg cleaning fluidsand diesel, can also occur. If the grain is visibly mouldy or dusty, do not smell it. Moulds and grain dust can be harmful and cause respiratory problems.

While the Agriculture and Horticulture Development Board seeks to ensure that the informationcontained within this document is accurate at the time of printing, no warranty is given in respectthereof and, to the maximum extent permitted by law, the Agriculture and HorticultureDevelopment Board accepts no liability for loss, damage or injury howsoever caused (includingthat caused by negligence) or suffered directly or indirectly in relation to information and opinionscontained in or omitted from this document.

Reference herein to trade names and proprietary products without stating that they are protecteddoes not imply that they may be regarded as unprotected and thus free for general use. Noendorsement of named products is intended, nor is any criticism implied of other alternative, butunnamed products.

AHDB Cereals & Oilseeds is a part of the Agriculture and Horticulture Development Board (AHDB).

Actual size

Actual size

Actual size

Actual size

Actual size

Actual size

Actual size