Hazard to food safety
Foodborne hazard
- biological - bacteria, viruses, parasite
- chemical - toxic substances that may occur naturally (during food processing)
- physical - any foreign object in food that can cause illness and injury (hair, nail, staple)
Bacteria
- aerobic - need oxygen to grow
- anaerobic - cannot survive when oxygen presence and all bacteria can grow, reproduce, and produce waste
1. spore forming bac
§ able to form, help bac survive when the environment to hot cold, dry, or acidic or when not enough food
§ temp. danger zone and more than 4 hour (5˚c - 60˚c)
§ harder to destroy
§ exp: bacillus cereus, closlidium perfringens
2. non-spore forming
§ not capable to form spores, easy destroy by cooking and cooling
§ exp: escherichia coli, salmonella
3. viruses
§ smaller that bac
§ need living host to multiply
§ exp: hepatitis A, Norwalk virus- JE, bird flu
4. parasites
§ small or microscopic creatures- live in or on another from whose body it obtains nourishment
§ exp: anisakis SPP, trichinella spireliss (in pork)
5. spoilage and disease ( causing bac)
§ it will degrade food.
§ look, taste, and smell bad - reduce quality of food
6. pathogenic bac
§ disease causing microorganisme that can make people ill if their toxins are consumed with food
several type of bac:
- psychrophilic
Ø bac. grow 32˚F to 70˚F (0˚C to 43˚C)
Ø become capable to multiply in both refrigerated and room temp
Ø most are spoilage bac but some can cause disease
- mesophile
Ø bac. grow 70˚F to 110˚F (21˚C- 43˚C)
Ø most rapid growth in human body (37˚C)
- thermophile
Ø bac that grow best at above 43˚C
Ø time and temperature - critical factor affecting bac growth
Ø careful time and temp to avoid temp abuse
Ø bac need 4 hours to grow to high enough number to caused illness
6 conditions bac growth (FATTOM)
- Food - high in protein, carbohydrate
- Acid - pH greater than 4.6
- temperature - dangerous zone (5˚C to 60˚C)
- super danger zone (21˚C to 49˚C)
- time - 4 hours cumulative time to allow bac to grow to high enough number to cause illness
- oxygen - aerobic
- anaerobic
- facultative anaerobic
- multi aerophilic
- moisture - water activity greater tan 0.85-lw
4 phase of bac growth:
- lag phase - bac exhibit little/ no growth, last only a few hours at room temperature
- log phase - bac. grow rapidly. some can double in number every 20 to 30 minutes
- stationary phase - the number of new bac. being produced equal the number of microorganism that are drying off. Bac. have used up most of the space, nutrients and moisture.
- decline stage - bac. die off rapidly bcos of lack nutrient or poisoned by their own waste.
iii.
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