jacobsen grain storage

8/2/2019 Jacobsen Grain Storage

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Maintaining Quality of Grains and

Managing Molds and Mycotoxins

Barry J. Jacobsen

Department of Plant Sciences and Plant Pathology

Bozeman, MT

1/6/09Crop pest Management School


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Grain is highest quality and lowest storage risk when fully

mature before harvest, absence of field mold damage,hail damage, lack of rain that delays harvest


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How did it happen?


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Moisture-not avera e moisture but moisture of wettest

component- affects ability of storage fungi to grow Temperature- affects growth rate of storage fungi and

BCFM-influences air movement, aeration, wet weed

seeds, etc ys ca amage o e erne or see

Mechanical-harvest and handling

Insects-field and storage

Stress cracks associated with high temperature drying

Infection b field molds


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Field Molds-infect in field and generally grow at moistures

> - n ecte erne s more suscept e to nvas on y storagefungi- may produce mycotoxins Aspergillus flavus-aflatoxins * can grow @16% enocarpe a may s p o a , e m n ospor um oc o o us Fusarium graminearum, pseudograminearum, culmorum, verticilliodes,

F. subglutinans, F, proliferatum (F. moniliformae)-, DON, fumonisins DON, DAS, T-2, HT-2, zearalenone

Nigrospora oryzae Penicillium species- ochratoxins, citrinin, penicillic acid and others

Cladosporium herbarum Alternaria sp.-alternariol, tenuazonic acid, etc Trichoderma viridae


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Generally non-toxic, ear molds of corn

Most common molds-Alternaria, CladosporiumRhizopus, Mucor, etc produce no known mycotoxins

a ospor umear ro


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n ec ons assoc a e w nsec amage earworm, corn orer ,high temperatures and droughty conditions during grain fill

Aspergillus flavus, A. parasiticus

Aflatoxins-B-1, B-2, G-1, G-2, M-1, M-2


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Gibberella zeaeearrotReddish-pink to white

Fusariummolds mayproduce DON (vomitoxin), zeara enone, - , - ,DAS

Cool, wet conditions in

21 days after pollination


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Favored by hot, dry weather atand after flowering-insect damage

Fusarium verticilliodes, F. subglutinans, F, proliferatum

(F. moniliformae)-Fusarium Kernel or Ear Rot-Fumonisins


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Fusarium verticilliodes, F.

, .(F. moniliformae)

*Warm,dry years

*

*Gibberella fujikuroi*Kernel damage promotes

the disease

* Less fumonisin in Bt

corns


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Gibberella Ear Rot

VOMITOXIN (DON) & ZEARALENONE

Corn: cool wet weather silking + 21 days, wet weather delayedarves

Wheat-Barley: 50-860

F anthesis +3-5 days-3 or more rain events


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19411941--19471947--Alimentary Toxic AleukiaAlimentary Toxic Aleukia--RussiaRussia--Central AsiaCentral Asia--wheat,wheat,barley, prosomillet overwintered in fieldbarley, prosomillet overwintered in field--trichothecene toxinstrichothecene toxinsfrom Fusarium sp.from Fusarium sp.

Fusarium-trichothecenes

Alternaria-Alternaria toxins

Wet weather delayed harvest-Field molds


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Dust= spores and hyphae of CladosporiumAs er illus Penicillium Alternaria


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Penicillium ear rot

en c um spp.

Source: D.W. White

c ra ox ns, s er ma ocyc n, remogen c ox ns, u eos yr n, a u n,Rubratoxin, Cyclopiazonic acid, Citrinin, Citreoviridin, etc


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-

in equilibrium with 65-90% relativehumidit

Members of the genera Aspergillus and

Penicillium These molds are nearly ubiquitous in the

environment

All corn kernels have these spores on theirsurface-infection is determined by:

, ,


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-

associated with decay of organic materials

Aspergilli favored by warm to hotcon ons

Penicillium favored by cooler conditions


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Water Activity

High Low Very Low

Eurotium spp.A.glaucus

torage o

Field Mold

Aspergillus flavusField/Stora e Mold


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Grain storage molds

As er illu and Penicilliums .

These fungi decay all seeds given theright commodity moisture andtem erature-some s ecies roducemycotoxins


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Equilibrium Moisture/Mold Growth% tarc y

grainsoy ean,

pea, bean,lentils

eanut,canola,camelina,

ung

safflower65-70 12.5 12.0 5.0 A. halophilcus/

A. restrictus

70-75 14.0 13.0 6.0 A. glaucus

75-80 15.0 14.0 7.0 A. candidus

80-85 16.0 15.0 8.0 A. flavus

Penicillium sp85-90 18.0 18.0 10.0 Above +Penicillium

>95 22.0 20.0 13.0 Yeasts/ bacteria

/most field molds


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Aspergillus glaucus


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Penicillium sp.


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Bin Burning associated with Aspergillus glaucusand A. candidus


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combustion due to storage mold activity


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Bin Burning of soybean-

sperg us g aucusanA. candidus


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Aspergillus restrictusSlow growing!!!Surface-white to greenReverse-paleBiseriate

reen con a

Long columnar head

Grows at equilibrium moistureof 65-70%13.5-14.3%

Discolors germs-brown-blackOften associated withgranary weevilsUsually a factor in long storage

ro uces mo sture to a owA. glaucusto grow


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Surface-green with yellow areasReverse-yellow to brownUniseriate

Loosely columnar headSome strains with yellow

Grows at equilibrium moistures-

Grows fairly fastEarly decayProduces moisture

that allows fast growingA. candidus to grow

types


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As er illus versicolor

Surface-white turns to yellow,, ,

Reverse-white to yellow-purple redBiseriate

oun oose y ra a e ea

Similar to A. glaucusbut later in decaySterigmatocystin


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Aspergillus candidus

Surface-white-reverse-pale to yellow orangeuniseriate

it can heat to 55C!- first step inspontaneous combustion

Grows at e uilibrium moisturesof 75-80%Presence in even a low %indicates spoilage is underway

or grain lot is mixed


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Aspergillus flavus


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. -

reddish brown-with age-

Round radiate Sclerotia in some strains

Grows at e uilibrium moistures>80-85%

~16% moisture for starchy cereal grains

-


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Penicillium ear rot

en c um spp.

Source: D.W. White

Penicillium sp


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Penicillium sp.

Penicillium sp. grow at equilibrium moistures > 85%


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Aspergillusand Penicilliumspp. on wheat

Source: C.M. Christensen

35 day voyage


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Average moisture at loading 14.97%

35 day voyageConvent, LA to Nagoya, Japan

ange n v ua erne s . - .


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Corn storage life* in days as affected

by temperature and moisture

0F

13 14 15 16 17 18

40 4500 1830 870 450 282 183

60 1410 570 186 150 90 57

70 780 330 156 84 51 33

80 450 180 87 48 27 27

* To prevent>0.5% dry matter loss-USDA-Iowa State


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orn storage essons

Lon er stora e without lossin quality at lower temperature

in quality with lower levels

of broken kernels


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Wheat


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Pea seed germination as affectedby storage molds


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Moldy clumps: usually starts in areas of high moisture seeds(weed, immature kernels or where transferred

block air movement


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Moisture content of the grain-individual seeds

Temperature of the grain-higher= faster moldgrowth

Amount of broken seeds and foreign material

emem er wee see s are o en g er mo s ure angrain

Pulse crops harvest moisture

Degree which the grain is invaded by insects andmolds- pre-harvest-post harvest

When molds and insects grow they produce

metabolic heat and water-succession of organisms


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In hi h risk areas- corn h brids are available with

reduced susceptibilty to Gibberella ear rot, Fusarium ear

rot and aflatoxin production-wheat varieties with scabresistance

Anticipate problems-weather drives preharvest infectionsrots caused by Gibberella, Fusarium, Aspergillus flavus

-combine-worn augers, watch high temperature drying-stress cracks

ean o remove wee see s, ro en gra n moinfected grain breaks up easily)-this will help aeration-spoutline of fines are often sites of initial mold activity

aeration


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temperature-remember storability is-

molds, insects will produce heat and

adjacent kernels!

-

Control storage insects

Remember moisture migration with

change of seasons


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Great reference on grain

Good general reference on critical


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Good general reference on criticalMoistures for various commodities

-trouble shooting


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Qualit Maintenance in stored rains and seeds-

Christensen and Meronuck-1986-Univ. MN

Press -

Christensen, Ed. 1982-Americam Association ofCereal Chemists

po age an ea ng o s ore agr cu uraproducts-Prevention Detection and Control-Mills-1989-Research Canada

Mycotoxins-Risks in Plant, Animal and HumanSystems-CAST 2003


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Qualit Maintenance in stored rains and seeds-

Christensen and Meronuck-1986-Univ. MN

Press -

Christensen, Ed. 1992-Americam Association ofCereal Chemists

po age an ea ng o s ore agr cu uraproducts-Prevention Detection and Control-Mills-1989-Research Canada

Mycotoxins-Risks in Plant, Animal and HumanSystems-CAST 2003


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Fungal metabolites that are toxic when consumed byanmas

Major classes of mycotoxins Aflatoxins, trichothecenes (DON, T-2, DAS), fumonisins,, , ,


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. - - -. ,

F. culmorum-DON, nivalenol, zearalenone -. , ,

F. graminearum-DON, nivalenol, zearalenone*

. - , , - , -

F. sporotrichioides-DAS, T-2, (HT-2)

. , . -fumonisins*

* Found commonly in corn

Mycotoxigenic Aspergillus and


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Mycotoxigenic Aspergillus and

Penicillium sp. A. flavus, A. parasiticus-aflatoxins *

A. versicolor, A. nidulellus(nidulans), A. terreus, some members

of the A. glaucus group- sterigmatocystin-most importantmycotoxin in stored wheat and other cereals in Canada and N.

A. alutaceus var alutaceus (ochraceous), A. melleus-

ochratoxins-warm to hot climates * A. fumigatus-gliotoxin * P. verrucosum, P. viridicatum-ochratoxin-cooler climates * P. islandicum-islanditoxin luteosk rin

P. rubrum-rubratoxins * Penicillium sp. citrinin, Penicillic acid, cyclopiazonic acid,

*

* Found in corn


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Anticipate based on weather Use resistant varieties where appropriate-corn, wheat

Fungicides where appropriate-wheat scab ~, Watch moisture-remember not average but individual

seeds

- - 12 truck loads-10 subsamples each: 0-230ppb

aflatoxin

ELISA kits -quantitative Aflatoxins, zearalenone, DON, T-2, Fumonisins

Immunoaffinity columns -quantitative Aflatoxins, zearalenone, DON, T-2, Fumonisins

Thank You & Happy Trails


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jacobsen grain storage

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