Food, science, hygiene. (Chapter 2)

Сентябрь 12, 2022

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Food, science, hygiene. (Chapter 2)

Содержание

2. Foodborn contamination Ensuring the safety of food is the managers most important job. A thorough understanding
3. Biological Contamination Microorganisms are small, living beings that can only be seen with a microscope. Helpful
4. Bacteria Smallest living celled organisms Found in Food, Water, Soil, Humans, Insects They can reproduce every
5. Bacteria growth pattern
6. Bacterial Growth continued There are 4 phases that bacteria go through Lag phase… Starting to adjust
7. Bacterial Growth Chart Bacterial Growth
8. Bacterial Growth
9. FOOD All food is susceptible to microorganisms, however they grow best in foods that are high
10. Acidity (pH) This is a measurement of the degree of Acidity or Alkalinity. The scale is
11. TEMPERATURE Bacteria grow best between the temperature of 5 degrees c and 60 degrees c (Temperature
12. MOISTURE There must be adequate moisture for bacteria to grow. The amount of moisture available is
13. CONTROLING THE GROWTH OF MICROORGANISMS Adding lactic or citric acid (Vinegar/ Lemon) pH Adding sugar or
14. VIRUSES Viruses are the smallest of the microbial contaminants. They consist of genetic material wrapped with
15. BASIC CARACTERISTICS OF VIRUSES Unlike bacteria they rely on a living cell to reproduce They are
16. PARASITES Parasites need a live host to survive Person, Animal or Plant Cattle, Poultry, Pigs and
17. MOULDS Individual mould cells can usually be seen only with a microscope, however fuzzy or slimy
18. MOULDS continued Moulds are responsible for the spoilage of food, that results in discoloration and the
19. MOULDS continued Some moulds produce toxins that can cause allergic reaction, nervous system disorders and kidney
20. BASIC CHARACTERISTICS OF FOODBORN MOULDS continued Trim back or throw away moldy food unless the mould
21. YEASTS Yeast is best known for producing bread and beer, however Yeast can spoil food by
22. BIOLOGICAL TOXINS Ciguatera poisoning… reef fish Paralytic poisoning… shell fish Scombroid poisoning… spoiled fish Some plants
23. CHEMICAL CONTAMINATION Chemical contaminants are responsible for many cases of foodborne illness, they may come from
24. TOXIC METALS Utensils and equipment that contain toxic metals such as Lead, Copper, Brass, Zinc, can
25. CHEMICALS AND PESTICIDES Chemicals such as cleaning products, polishes, lubricants and sanitizers can contaminate food Always
26. PHYSICAL CONTAMINATION Physical contamination can occur when foreign objects are accidentally introduced into food Examples;- Natural
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Слайд 2

Foodborn contamination
Ensuring the safety of food is the managers most important

job.
A thorough understanding of the causes and prevention of various types of contamination can help you keep the food safe.

Слайд 3

Biological Contamination
Microorganisms are small, living beings that can only be seen

with a microscope.
Helpful Bacteria
Yeast for bread, Rennet for cheese
Harmful Bacteria
cause food poisoning, Pathogens

Слайд 4

Bacteria
Smallest living celled organisms
Found in Food, Water, Soil, Humans, Insects
They can

reproduce every 20 mins ( double )
Some can survive freezing
Some can turn into spores to protect themselves
Some can produce toxins as they multiply, die and break-down. These are not destroyed by cooking

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Bacteria growth pattern

Слайд 6

Bacterial Growth continued
There are 4 phases that bacteria go through
Lag phase…

Starting to adjust to environment
Log Phase… In favorable conditions Rapid growth
Stationary phase… Nutrients used and waste accumulates
Death phase… nothing left to support growth, and all waste, bacteria die

Слайд 7

Bacterial Growth Chart
Bacterial Growth

Слайд 8

Bacterial Growth

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FOOD
All food is susceptible to microorganisms, however they grow best in

foods that are high in protein, and/or Carbohydrates
Meat, Poultry, eggs
Dairy products. Milk, Cheese, cream

Слайд 10

Acidity (pH)
This is a measurement of the degree of Acidity or

Alkalinity. The scale is 0 – 14
A pH of 7 is neutral.
Bacteria grow best between 4.6 to 7.5
0 7 14
Acidity ----------Neutral-----------Alkalinity

Слайд 11

TEMPERATURE
Bacteria grow best between the temperature of
5 degrees c and

60 degrees c
(Temperature danger Zone)
They will begin multiplying again if given the correct conditions

Слайд 12

MOISTURE
There must be adequate moisture for bacteria to grow. The amount

of moisture available is defined as water activity (aw)
It is measured on a scale 0 through 1
with 1 = to 100% of water available for the bacteria to use
Bacteria grows best between 0.85 – 0.97
Dried foods. Dried milk is 0.2 Crackers 0.3

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CONTROLING THE GROWTH OF MICROORGANISMS
Adding lactic or citric acid (Vinegar/ Lemon)

pH
Adding sugar or salt (lower water activity) aw
Vacuum packing ( deny oxygen)
Don’t allow food to stay at temperatures between 5 – 60 degrees c (the danger zone)
Prepare small batches if possible

Слайд 14

VIRUSES
Viruses are the smallest of the microbial contaminants. They consist of

genetic material wrapped with an outer layer of protein.
Whilst a virus cannot reproduce outside a living cell, once inside a human cell, it will produce more viruses, such as Hepatitis A

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BASIC CARACTERISTICS OF VIRUSES
Unlike bacteria they rely on a living cell

to reproduce
They are not complete cells
They do not reproduce in food
Some may survive freezing and cooking
They can be transmitted from person to person
They can be transmitted from people to food
Usually transmitted by improper hygiene
They can contaminate both food and water supplies

Слайд 16

PARASITES
Parasites need a live host to survive
Person, Animal or Plant
Cattle, Poultry,

Pigs and Fish
Vegetables and Fruit
Usually passed to humans by meat or Fish
Precautions:
Ensure food is from an approved source
Use proper cooking to avoid cross contamination
Use clean water, and follow personal hygiene

Слайд 17

MOULDS
Individual mould cells can usually be seen only with a microscope,

however fuzzy or slimy mould colonies consisting of a large number of cells are often visible to the naked eye.
Bread mould is an example.

Слайд 18

MOULDS continued
Moulds are responsible for the spoilage of food, that results

in discoloration and the formation of odours and off-flavors
Moulds can grow on most foods at most temperatures in most environments… moist, dry, high or low pH, salty or sweet
They prefer to grow on and in acidic food with a low water activity
Examples;- Fruit, Vegetables, Meat, Cheese, Bread

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MOULDS continued
Some moulds produce toxins that can cause allergic reaction, nervous

system disorders and kidney and liver damage.
Examples;-
Corn, and Corn products
Peanuts and peanut products
Brazil nuts, Pecans, pistachio and wallnuts have all been associated with aflatoxins.

Слайд 20

BASIC CHARACTERISTICS OF FOODBORN MOULDS continued
Trim back or throw away moldy

food unless the mould is a natural part of the food
Examples;-
Gorgonzola, Blue, Brie, Camembert
NOTE: While mould cells can be killed by heating them, toxins that may be present are NOT destroyed by normal cooking methods

Слайд 21

YEASTS
Yeast is best known for producing bread and beer, however
Yeast can

spoil food by giving of carbon dioxide and alcohol as it slowly consumes the food, leaving a smell or taste of alcohol
Yeast prefers the same conditions as moulds

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BIOLOGICAL TOXINS
Ciguatera poisoning… reef fish
Paralytic poisoning… shell fish
Scombroid poisoning… spoiled fish
Some

plants may be toxic in their raw state, but safe when properly cooked
Some beans may be toxic if eaten raw or uncooked,
Examples;- Fava beans, Red kidney beans

Слайд 23

CHEMICAL CONTAMINATION
Chemical contaminants are responsible for many cases of foodborne illness,

they may come from a variety of substances normally found in restaurants and foodservice establishments… these include Toxic metals
Pesticides
Chemicals

Слайд 24

TOXIC METALS
Utensils and equipment that contain toxic metals such as Lead,

Copper, Brass, Zinc, can cause a toxic poisoning. If acidic food is stored in or prepared using these types of utensils or equipment it can leach toxins into the food.
Examples;-
Tomato sauce in copper,
Lemonade in pewter

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CHEMICALS AND PESTICIDES
Chemicals such as cleaning products, polishes, lubricants and sanitizers

can contaminate food
Always read manufactures instructions
Store away from food in locked cupboard
Always…. leave in original containers
Never…. transfer into other containers
Some chemical combinations can KILL !!!
(bleach & ammonia)

Слайд 26

PHYSICAL CONTAMINATION
Physical contamination can occur when foreign objects are accidentally introduced

into food
Examples;-
Natural objects… Bones ect
Metal, staples, glass, plastic, pins, plasters

Food, science, hygiene. (Chapter 2)

Содержание

Foodborn contaminationEnsuring the safety of food is the managers most important

Biological ContaminationMicroorganisms are small, living beings that can only be seen

BacteriaSmallest living celled organismsFound in Food, Water, Soil, Humans, InsectsThey can

Bacteria growth pattern

Bacterial Growth continuedThere are 4 phases that bacteria go throughLag phase…

Bacterial Growth Chart Bacterial Growth

Bacterial Growth

FOODAll food is susceptible to microorganisms, however they grow best in

Acidity (pH)This is a measurement of the degree of Acidity or

TEMPERATUREBacteria grow best between the temperature of 5 degrees c and

MOISTUREThere must be adequate moisture for bacteria to grow. The amount

CONTROLING THE GROWTH OF MICROORGANISMSAdding lactic or citric acid (Vinegar/ Lemon)

VIRUSESViruses are the smallest of the microbial contaminants. They consist of

BASIC CARACTERISTICS OF VIRUSESUnlike bacteria they rely on a living cell

PARASITESParasites need a live host to survivePerson, Animal or PlantCattle, Poultry,

MOULDSIndividual mould cells can usually be seen only with a microscope,

MOULDS continuedMoulds are responsible for the spoilage of food, that results

MOULDS continuedSome moulds produce toxins that can cause allergic reaction, nervous

BASIC CHARACTERISTICS OF FOODBORN MOULDS continuedTrim back or throw away moldy

YEASTSYeast is best known for producing bread and beer, howeverYeast can

BIOLOGICAL TOXINSCiguatera poisoning… reef fishParalytic poisoning… shell fishScombroid poisoning… spoiled fishSome

CHEMICAL CONTAMINATIONChemical contaminants are responsible for many cases of foodborne illness,

TOXIC METALSUtensils and equipment that contain toxic metals such as Lead,

CHEMICALS AND PESTICIDESChemicals such as cleaning products, polishes, lubricants and sanitizers

PHYSICAL CONTAMINATIONPhysical contamination can occur when foreign objects are accidentally introduced

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