Risk of Food spoilage Some foods are high-risk, as they provide the ideal conditions needed for micro- organisms to grow. These include:  Meat & Poultry products.  Milk and dairy products;  Fruit. 10. Risk of Food spoilage in Meat & Poultry Risk increases when:  Sliced or Minced.  Kept uncovered. Kept Moist.  Kept at Danger Zone Temperature 11. Risk of Food spoilage 12. Risk of Food spoilage Food Can be Classified into:  Perishable food: meats, fish, poultry, eggs, milk, most fruit and vegetables  Semi-perishable food: potatoes, apples, nuts  Nonperishable food: sugar, flour, rice, dry beans, or Processed prepackaged food 13. Non-perishable prepackaged Food Canned soda Boxed juice Bottled water Chips Pretzels Granola bars Crackers Candy 14. Cooked Food Risk of Spoilage General rule after Cooking: “Keep Hot Food Hot, Keep Cold Food Cold” High Risk of Food spoilage High Risk of Food Borne diseases. Leftovers should be stored carefully, Doubtful food shouldn’t be consumed. 15. Canned Food  Generally, Canning has excellent keeping quality of Food,  Why? Compined 2 or more techniques for food preservation  Sealing (Oxygen Deprivation)  ±Heating  ±Salting  + Acidification 16. Spoilage in Canned Food  Spoilage occurs due to some faulty technique:  Eg:  Not properly Sealed  Not properly Heated  Acid from food reacts with iron of container  Canned food which is doubtful should be discarded without tasting the contents. 17. Signs of Spoilage in Canned Food  Can has swollen irregular appearance  Can is leaky or corroded.  Can is rusty  Contents smell putrid or alcoholic  Contents are discoloured  Syrup looks turbid, cloudy, slimy or mouldy.  Contents spurt out when the can is opened. 18. Signs of Spoilage in Canned Food 19. Signs of Spoilage in Canned Food 20. Signs of Spoilage in Canned Food 21. Signs of Spoilage in Canned Food 22. Signs of Spoilage in Canned Food 23. Signs of Spoilage in Canned Food 24. Frozen Food  Its is hard to detect spoilage in frozen food, unless there are obvious changes in colour and smell, mainly when it is thawed.  Freezing only slows bacterial growth, but doesn’t completely kill bacteria if present in food.  Bacteria can multiply again when food is thawed and temperature reaches the “Danger Zone”.  Rule: Frozen Food, once thawed is highly perishable. 25. Temperature Danger Zone 5°C and 60°C 26. Rules for handling Frozen Food  Don’t use frozen food if it has a bad smell, taste or colour.  Thaw only what you need.  Don’t re-freeze thawed food.  Don’t buy or use damaged outer package  Don’t keep frozen food out of the freezer long before cooking or serving  Don’t accept frozen food which has a large quantity of ice crystal formed inside the package.

1. By:
Dr. Waleed Foad
MSc.Public Health in Nutrition
Clinical Nutrition Specialist
European Society of Gastrointestinal Endoscopy (ESGE)
Member of the American Society of Nutrition
Email: wfoad@outlook.com

2. Topics Covered in Previous Lectures
 Some Definitions:
 Nutrition
 Hygiene
 Food Hygiene
 Food Spoilage
 Food Contamination
 Foodborne disease (Food Poisoning)
Introduction to
Nutrition and Food Hygiene

3. Topics Covered in Previous Lectures
 Types and Characteristics of Microorganisms that affect
Food.
 Symptoms of Bacterial Food Poisoning
 Types of Bacterial food poisoning:
1. Food intoxication
2. Foodborne Infection
Bacterial food poisoning

4. Factors needed for Microbial Growth
 Microbial Growth and multiplication is influenced by:
1. Food (nutrients for bacteria).  F
2. Acidity (Suitable pH)  A
3. Time.  T
4. Suitable Temperature.  T
5. Oxygen (Most of them, but not all).  O
6. Moisture (Water content) M
Remember: Bacteria need “FAT TOM” to Multiply
Topics Covered in Previous Lectures

5. Temperature of food
Under ideal conditions, bacteria multiply rapidly between
5°C and 60°C (the danger zone for food).
 Below 5°C, bacteria multiply slower.
 At freezing temperatures, bacteria stop multiplying and
become dormant. Freezing does not kill bacteria.
 Most bacteria are killed at temperatures above 60°C.
Topics Covered in Previous Lectures

6. Temperature Danger Zone
5°C and 60°C
Topics Covered in Previous Lectures

7. Food Preservation Methods
Topics Covered in Previous Lectures
 Changing Acidity: e.g. Chemical preservatives.
 Changing Temperature: e.g. Cooking, Refrigeration,
Pasteurization, Freezing.
 Oxygen Deprivation: e.g. Smoking, Vacuum and
Canning.
 Water (Moisture) Deprivation: e.g. Drying, Salting
and Sugaring.

8. Preservation using Multiple techniques.
 Combined 2 or more techniques for food
preservation may be used, Example:
 Canning: Heating and oxygen deprivation.
 Pasteurization: Heating and oxygen deprivation.
 Salted Fish Canning: Salting & oxygen deprivation
 Freeze Drying: Freezing, Drying & Oxygen
Deprivation.
Topics Covered in Previous Lectures

10. Risk of Food spoilage
Some foods are high-risk, as they provide
the ideal conditions needed for micro-
organisms to grow.
These include:
 Meat & Poultry products.
 Milk and dairy products;
 Fruit.

11. Risk of Food spoilage in Meat & Poultry
Risk increases when:
 Sliced or Minced.
 Kept uncovered.
Kept Moist.
 Kept at Danger
Zone Temperature

12. Risk of Food spoilage

13. Risk of Food spoilage
Food Can be Classified into:
 Perishable food: meats, fish, poultry, eggs,
milk, most fruit and vegetables
 Semi-perishable food: potatoes, apples,
nuts
 Nonperishable food: sugar, flour, rice, dry
beans, or Processed prepackaged food

14. Non-perishable prepackaged Food
Canned soda
Boxed juice
Bottled water
Chips
Pretzels
Granola bars
Crackers
Candy

15. Cooked Food Risk of Spoilage
General rule after Cooking:
“Keep Hot Food Hot, Keep Cold Food
Cold”
High Risk of Food spoilage
High Risk of Food Borne diseases.
Leftovers should be stored carefully,
Doubtful food shouldn’t be consumed.

17. Canned Food
 Generally, Canning has excellent keeping
quality of Food,
 Why?
Compined 2 or more techniques for food preservation
 Sealing (Oxygen Deprivation)
 ±Heating
 ±Salting
 + Acidification

18. Spoilage in Canned Food
 Spoilage occurs due to some faulty technique:
 Eg:
 Not properly Sealed
 Not properly Heated
 Acid from food reacts with iron of container
 Canned food which is doubtful should be
discarded without tasting the contents.

19. Signs of Spoilage in
Canned Food
 Can has swollen irregular appearance
 Can is leaky or corroded.
 Can is rusty
 Contents smell putrid or alcoholic
 Contents are discoloured
 Syrup looks turbid, cloudy, slimy or mouldy.
 Contents spurt out when the can is opened.

20. Signs of Spoilage in Canned Food

21. Signs of Spoilage in Canned Food

22. Signs of Spoilage in Canned Food

23. Signs of Spoilage in Canned Food

24. Signs of Spoilage in Canned Food

25. Frozen Food
 Its is hard to detect spoilage in frozen food,
unless there are obvious changes in colour and
smell, mainly when it is thawed.
 Freezing only slows bacterial growth, but doesn’t
completely kill bacteria if present in food.
 Bacteria can multiply again when food is thawed
and temperature reaches the “Danger Zone”.
 Rule: Frozen Food, once thawed is highly
perishable.

26. Temperature Danger Zone
5°C and 60°C

27. Rules for handling Frozen Food
 Don’t use frozen food if it has a bad smell,
taste or colour.
 Thaw only what you need.
 Don’t re-freeze thawed food.
 Don’t buy or use damaged outer package
 Don’t keep frozen food out of the freezer long
before cooking or serving
 Don’t accept frozen food which has a large
quantity of ice crystal formed inside the
package.

28. Spoilage of Frozen Food

29. Spoilage of Frozen Food

30. For Further Support:
Dr. Waleed Foad
Email: wfoad@outlook.com