AGEN2002 Study Guide - Quiz Guide: Microorganism

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maroontiger294

15 May 2018

School

University of Sydney

Department

Agricultural Genomics

Course

AGEN2002

Professor

agen2002

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Lecture910(WK5)MEAT

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Postharvestspoilageofmeatandseafoodproducts

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Spoilage

● Abnormalbacterialevel

● Unacceptableoffodour

● Unacceptableoffflavour

● Nondesirableappearance

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Factorsthataffectshelflife

1. Extrinsicfactors/environment(amountofavailablemoisture,temperature,lighting,

packaging)

○ Temperature:meatstoredbelow3’C,topreventbacteriagrowth

i. Psychotrophs:bacteriathatlivesincoldconditions

ii. Mesophiles:human/animalbacteria&welladjustedtobodytemp

iii. Thermophiles:inappropriatecooking&storage

○ Packaging

i. Shelflifeofmeatincreasesintheorderof:

Air<highoxygenMA<vacuum<nooxygenMA<100%CO2

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2. Muscletissuefactors(pH,musclefibers)

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3. Microorganismstype&level(bacteria/fungietc)

○ Contaminationfromprocessing,animalparts,packaging(equipment/bad

technique)

○ Water/moisture

○ Air/dust

○ Poorsanitation

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4. Enzymes

○ Breakdownofstructurecanaidinincreasedfluidleakingduringageing

○ Thisproteinrichfluidprovideenvironmentforbacteriatoproliferate

(antimicrobialabsorptionpadsinpackagingtosoakupfluid)

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5. Chemicals(productscreatedasaresultfromactivityofmicroorganisms/enzymes)

○ Chemicalreactions

i. Fatoxidation→rancidity

ii. Muscleoxidation→changeinmeatcolour

○ Chemicalparametersofmeatcaninfluencemicrofloracolonyproliferationdueto

acidity,mineralcontent&amountofmoistureofmeat 

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AGEN2002 Study Guide - Quiz Guide: Microorganism

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