Changes

1Microbiological

aMoulds-most common,microscopic fungi,bad.Needs little humidity.pH4

byeast-oval-shaped fungi,good.Needs a bit humidity.pH6.5

cbacteria-Cocci-spherical,Bacilli-rod shaped.Needs humidity.pH8.5

iSpoilage organisms-not harmful,lactobacillus

iiPathogens-disease causing organisms

some pathogens cause food poisoning,other(salmonella)give rise to illness

Growing phases-lag,exponential,stationary & death

Temp-psychrophilic(10-15 H2O born),mesophilic(20-40 salmonella),thermophilic(55-65 spore forming)

Aerobic will grow in the presence of oxygen,anaerobic not

iSalmonella enteritidis-causes diarrhoea,eggs,destroyed by heath

iiCampylobacter jejuni-main UK food poisoning,cramps,diarrhoea.Raw chicken + milk

iiiListeria monocytogenes-only old/young,causes meningitis,soft cheeses,heath sensitive

ivStaphylococcus aureus-carried in the skin,releases heath-proof toxin

vClostridium botulinum-soil+seawater,form spores,50%mortality

Cook fast at high t.consume quickly,do not hold long in refrigerator

2Biochemical reactions

Depends when harvested.Changes are due to enzymes

E.g.pectin breakdown makes mushy

3cooking or preserving