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FT 114 - Dairy Products Technology | Jan Isobel Hidalgo | SY 14-15
MICROBIOLOGY QUICK REVIEW
Important microbes in food?
Bacteria
Fungi
Mold
Yeast
Bacteria
Single-celled microorganisms
Can transform into spores
Reproduce by binary fission
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FT 114 - Dairy Products Technology | Jan Isobel Hidalgo | SY 14-15
FUNGI: Molds
Multi-cellular colonies that form intertwined and branching hyphae or
filament
Grows best in moist warm temperatures
Requires less moisture than bacteria and yeast
Reproduce by means of spores
FUNGI: Yeast
Single-celled fungi
Larger cell size than bacteria
Grow in numbers by dividing (budding or fission)
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FT 114 - Dairy Products Technology | Jan Isobel Hidalgo | SY 14-15
Most are not pathogenic
Used in bread making, alcohol fermentation
Microbial Growth
Nutrient requirement
Water
Energy source
Carbon/nitrogen source
Vitamins and minerals
Moisture
Two types of water
Bound
Free water (aw)
Preferred aw = 0.99
Needed aw > 0.91
Spoilage bacteria aw > 0.90
Yeast and molds can grow @ aw of 0.80.
Most fungi aw > 0.70
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FT 114 - Dairy Products Technology | Jan Isobel Hidalgo | SY 14-15
Temperature Requirements
Classification Minimum C
OptimumC
Maximum C
Thermophiles 40 to 45 55 to 75 60 to 90
Mesophiles 5 to 15 30 to 37 45
Psychrophiles -5 to 5 12 to 15 15 to 27
Psychrothrops -5 to 5 30 - 37 45
pH needs and microbes
Neutrophiles
Acidophiles
Alkalinophiles
Oxygen
Aerobic
Anaerobic
Facultative anaerobe
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FT 114 - Dairy Products Technology | Jan Isobel Hidalgo | SY 14-15
Next Meeting
QUIZ
Main Sources of contamination
Microorganisms in Milk