Food preservation - necessity & methods. Cold chain.

1. FOOD PRESERVATION
Necessity
Methods
Cold Chain
References:
1) R.S.Khurmi, J.K.Gupta
2) Arora & Domkundwar
3) IIT Khragpur Notes

2. Applications of Refrigeration
Four major areas:
 a) Food preservation
 b) Chemical and process industries
 c) Special Applications
 d) Comfort / industrial air-conditioning

3. Food Preservation
What is food preservation?
Retaining food over a period of time without
being contaminated by pathogenic organisms
or chemicals and without losing its colour,
texture, flavour and nutritious value.
Why food preservation?
 Seasonal availability of food
 Different type of food at different locations

4. Food Preservation
a) Food processing:
Slow freezing or sharp freezing
Quick freezing
Air blast freezers
b) Food Preservation:
Cold storages
c) Distribution:
Refrigerated vehicles

5. Food Preservation
Advantages:
 Increases the shelf life of food
 Retain the quality of food – colour,
texture, flavour & nutrition value
 Increases food supply
 Adds variety to the food
 decreases wastage of food

6. Food Preservation
Food Product Average Useful Storage life
(days)
0oC 22oC 38oC
Meat 6-10 1 <1
Fish 2-7 1 <1
Poultry 5-18 1 <1
Dry meats and > 1000 > 350 & >100 &
fish < 1000 < 350
Fruits 2 - 180 1 – 20 1–7
Dry fruits > 1000 > 350 & >100 &
< 1000 < 350
Leafy vegetables 3 - 20 1–7 1–3

7. RECOMMENDED STORAGE TEMP
PRODUCT STORAGE TEMP
MILK 4 DEGC
BUTTER 2 TO 8 DED C
ICE CREAM (-) 20 TO (-)22 DEG C
VEGETABLES 2 TO 8 DED C
FRUITS 0 TO 4 DEG C
MEAT (-) 20 DEG C
PHARMA PRODUCT 2 TO 8 DED C
FROZEN FISH (-) 18 TO (-) 29 DEGC
CHEESE (-) 18 DEG C
SWEETS 2 TO 8 DED C

8. F
 .R
I
D
G
E

9. Food spoilage
 Food components:
 Proteins
 Carbohydrates
 Fats
 Vitamins
 Minerals
 Destruction of any of these component
is food spoilage.

10. Cause of food spoilage
 Spoilage due to physical change
impact, bruising and squeezing
desiccation or dehydration
 Spoilage due to chemical change
internal spoiling agents : Enzymes
external spoiling agents:
bacteria, yeast, moulds (fungus)

11. Methods of food preservation
 Heat processing
 Dehydration
 Chemical preservation
 Canning
 Pasteurization
 Freezing

12. Freezing for food
preservation
 Slow or sharp freezing
 Quick freezing
smaller ice crystals
no separation of minerals, salts
Immersion freezing
Indirect contact freezing
Air blast freezers

13. Cold stores
 To store food products after processing
 Prefabricated insulated panels
 Air tight door in sandwich construction
 Safety anti-locking arrangement
 Temperatures – positive or sub-zero
 Layout – air lock, sorting-cum-intermediate
storage area, store compartments
 Important points – temperature, RH, air
motion, product mix, duration

14. Prefabricated Cold store

15. Cold Storage: FCUs

16. Cold Storage : Interior

17. Cold Storage : Material
Arrangement & Air Movement

18. Cold Chain
Cold chain is a temperature-controlled
supply chain.
 Pre-cooling chambers at farm
 Processing unit – freezing, packing
 Manufacturer’s cold storage
 Distributor’s cold storage
 Retailer’s cold storage
 Refrigerated display cabinets
 Residential refrigerator
 Refrigerated transport

19. COLD CHAIN : TOTAL SOLUTIONS
Distribution Center Retail
Source Precooling Transport
` Processing Shipping

20. CARRIER COMMERCIAL REFRIGERATION
Cold chain
Farms/food processors Multinational
hypermarkets
Distribution Regional supermarkets
centers
Cash and carry Convenience stores
Carrier OMM II 2005
0

21. Pre-Cooling
of
Fruits & Vegetables

22. Methods of Pre-cooling
Different methods of Pre-Cooling includes:
1) Hydrocooling
2) Vacuum Cooling
3) Forced Air Cooling
4) Contact Icing
5) Evaporative Cooling
Caution. No matter what cooling method is employed, the produce
should never be allowed to re-warm once it has been cooled.

23. Blast Freezing Application
• Seafood
• Poultry, Meat
• Fruit & Vegetable
• Ready Meals

24. Cold Storage Application
• Distribution/Logistic Center
• Frozen produce
• Processing Room

25. CA Storage Application
Storage comparisons for a typical Apple: