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