Oxygen is a key factor in food storage and can cause oxidation resulting in chemical changes to stored foods. Removing oxygen through techniques like displacing it with inert gases like nitrogen or using oxygen absorbers prevents this oxidation. Foods should be stored in dark, cool areas in food-grade containers away from light and high temperatures to best preserve nutritional quality and appearance. Canned foods can be stored safely for long periods if properly processed and stored in cool, dry conditions away from temperature extremes. The First In First Out (FIFO) method helps ensure the oldest stock is used first to maximize food freshness and safety.

1. Y.Bavaneethan.
Lecturer
Department of Food Technology
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2. • Oxygen is a key element in the storage of dried foods.
• Oxygen can cause an oxidization process that,
• creates a chemical change in the properties of stored foods.
• Foods store best when oxygen free.
• Removing oxygen - prevent oxidation of compounds in
foods.
Ways to remove oxygen
Displacing oxygen:
• Remove air from product with an inert gas (nitrogen).
• Dry ice is often used (solid CO2)
• gives off carbon dioxide gas that displaces oxygen.
• When using dry ice,
• push the air out of the container.
• it may expel oxygen – hazard to storage place
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3. Oxygen absorber:
• If the oxygen is absorbed,
• remains 99 percent pure nitrogen in a partial vacuum.
• Seeds store better in nitrogen.
• However, if using seeds for sprouting or garden,
• store in oxygen.
Light:
• Effect of degrading nutritional content and appearance.
• Fat soluble vitamins, such as A, D, and E, fats and
• proteins are sensitive to light degradation.
• When opening a glass jar of food
• finding the food inside two-toned
• Reasons - exposed to too much light.
• Store food in dark areas.
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4. • Store foods in food-grade plastic, metal, or glass
containers.
• Containers should not contain chemicals that,
• transferred to food and harmful to health.
• If reusing previous food containers,
• particularly those that are plastic,
• be aware that plastic can absorb molecules and
• If contains smells and flavors of previous contents
• that can be transferred
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5. Warning –
• Botulism poisoning can occur,
• if moist products are stored in packaging with
absence of oxygen.
• When storing foods in airtight containers with oxygen
absorbers,
• products must be dry (about 10 percent or less
moisture content).
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6. DRIED MEATS
• Drying, smoking, and curing (salting) meat,
• to preserve for longer storage
• Drying, or dehydrating,
• purpose - extending the meat for storage
• But it is one of the processing steps for specific meat
products,
• salami.
• These meats are considered a “fermented” meat.
• Dried meats generally fall under two main categories:
• fermented and non-fermented.
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7. • Fermented meats (also known as salted/cured meats)
• prepared with salts and
• spices for flavor, and combined with drying.
• these meats safe for longer-term storage
• with or without refrigeration (depending on the meat)
• Moisture reduced to between 15 percent-50 percent weight
loss, depending on the meat product.
• In these products,
• drying and fermenting go hand in hand order
• desired flavor and shelf life safely
• Controlled and specific environment
• temperatures, time, and humidity controls established.
• Examples of fermented meats are salami and chorizo.
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8. • Non-fermented dried meats are another category.
• The production techniques used,
• at non-refrigerated storage temperatures.
• These meats are most common and typical to a dry pack
food storage program.
• There are two ways for drying meat for storage.
• freeze drying, and dehydrating.
• Both methods are used commercially,
• but dehydrating is readily available for home production
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9. • Freeze Drying:
• A process for preserving foods,
• Including meats,
• Actually started in World War II.
• freeze drying serums medically viable without
refrigeration.
• Freeze drying involves flash freezing the cooked meat,
• then drawing off the water through a process called
“sublimation.”
• Freeze dried meats most common form of commercially
prepared meats.
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10. • Dehydrated (or Drying):
• drawing off moisture through the use of low heat (heat
adequate to dry food out) and air flow.
• Meats prepared and preserved
• at home food storage, and
• used commercially as well.
• Home production of dried foods can be done both
• Outdoors (sun or solar drying), or
• Indoors (oven or dehydrator).
• But, Sun and solar drying, are not recommended for home
production of dried meats
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11. Packaging
• Many different types of packaging are used for dried
meats,
• but all must be air-tight and moisture proof.
• This may include
• plastic laminated foil pouches or metal and fiber drums
for bulk packaging.
• Some freeze-dried food is vacuum packed,
• air is evacuated from the container before sealing.
• Inert gas like nitrogen injected into the container
• to displace the oxygen and prevent oxidation or
spoiling
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12. Storage conditions and shelf life
• Commercially prepared freeze dried meats need to stored
• in cool, dry conditions.
• Home produced dehydrated meats,
• stored in airtight containers - refrigerator or freezer
for long-term storage
• Shelf life for dried meats varies greatly, depending on
• manufacturer and type of method used for production.
• Freeze dried meats, commercially prepared,
• range from 10-25 years.
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13. DRIED EGGS
• Fresh eggs are so perishable
• The popularity of the dried or dehydrated eggs increased in
demand
• home food storage
• food service industry.
• Eggs - great source of many important nutrients,
• and inexpensive source of protein in their fresh form
• Egg brings many beneficial characteristics to baked goods,
• leavening (as in cream puff s)
• binding, emulsifying
• Thickening and coating.
• These properties are not allow to destroyed in the drying
process time.
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14. Packaging
• Dried egg products should be in a container that has a
tight, unopened seal.
• Most importantly, the packaging must prevent
• moisture and rodent/insect damage.
• Many suppliers package dried eggs
• in cans or well-sealed pouches.
• It is important to remember that once the packaging has
been opened,
• its shelf life decreases.
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15. Storage conditions and shelf life
• Dried eggs need to be stored in clean, cool, and dry conditions.
• Important to keep in as cool temperature as possible, without
freezing.
• temperature range of 50° to 60°F is ideal
• Shelf life for optimum quality and nutrition of dried eggs
• 1 to 2 years
• depending on storage temperature, and unopened.
• The quality and acceptability of dried eggs is not in favor of
long-term storage
• after opening,
• stored in air tight, cool, dry conditions.(refrigerate)
• re-package in smaller air tight container with oxygen
absorber.
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16. Canned Foods
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17. What are canned foods
• Canning is a method of preserving food
• food contents are processed and sealed in airtight container.
• Commercial canning is done under tightly controlled
conditions —
• careful sanitation and necessary time and temperature
under pressure.
• But need to know- how long preserve food.
• There are several factors that limit the shelf life of canned
foods.
• Cans can rust over time.
• Shipping accidents - cans fall and dent or are crushed, also
cause container problems.
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18. • can corrosion –
• especially in high-acid foods like canned tomatoes,
• natural chemicals in the food react with the
container.
• can cause taste and texture changes,
• eventually lower the nutritional value of the food.
• High temperatures (over 100 °F) are harmful to canned
goods store.
• The risk of spoilage
• Nutritional and sensorial
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19. Why Canning make food stable?
• Method of preserving - food is placed in airtight, vacuum-
sealed containers and heat processed at 250 °F (121 °C).
• This destroys microorganisms and inactivates enzymes.
• As the food cools, a vacuum seal is formed that,
• prevents any new bacteria from getting in.
• Food in the container is commercially sterile, it does not
spoil.
• Once the container is opened,
• bacteria can enter and begin growing in the food.
• unused portions must refrigerated in clean containers.
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20. Where to store the canned food products
1. Store canned foods and other shelf stable products in
a cool, dry place.
2. Never put them, any place exposed to high or low
temperature extremes.
3. Temperatures below 29 °C are best.
4. Don’t purchase bulging, rusted, leaking, or deeply
dented cans.
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22. Are all canned shelf stable?
• Some canned meat are shelf stable and can be stored up to 2
to 5 years at room temperature.
• They have been processed to kill all spoilage bacteria and
pathogenic organisms
• such as Clostridium botulinum, Salmonella, and
Trichinella spiralis.
• However, unusually high temperature storage — above 122
°F (50 °C) —
• may thermophilic bacteria multiplying and swelling or
souring the product.
• If this happens, not be kept in the storage.
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24. Is it safe to use rusted canned foods?
• Discard heavily rusted cans.
• heavily rusted can have tiny holes in them, allowing
bacteria to enter.
• Surface rust - remove by rubbing with your finger or a
paper towel is not serious.
• If you open the cans and there is any rust inside, do not
eat the food.
• Rust (oxidized iron) is not safe to eat.
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25. Is it safe to use cans that freeze accidentally?
• Cans of food that freeze accidentally,
• sub-zero temperatures,
• can present health problems.
• Frozen cans can swell because the food inside expanded
when frozen.
• However, cans could be swollen because of contamination
with Clostridium botulinum or spoilage causing organisms.
• Do not use any swollen cans; discard them.
• Cans that have thawed and refrozen are not safe.
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26. Clostridium botulinum
• Bacteria Clostridium botulinum (C. botulinum) is a very serious
danger in canned goods.
• Botulism is a deadly food poisoning. The botulism bacteria — rod
shaped under the microscope — grow best in anaerobic (absence of
oxygen) conditions.
• C. botulinum bacteria may find incorrectly or minimally processed
canned foods a good place to grow and produce the toxin.
• Low-acid vegetables such as green beans, corn, beets, and peas,
which may have picked up C. botulinum spores from the soil, are at
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27. • The botulism spores are heat-resistant,
• C. botulinum organism, it takes even higher temperatures to kill
the spore.
• That’s why the canning of low-acid foods is done with a pressure
canner.
• If you eat C. botulinum-contaminated food, symptoms will
develop in 12 to 48 hours.
• The poison attacks the nervous system, causing double vision,
droopy eyelids, trouble swallowing and difficulty breathing.
• There is an antitoxin, which has reduced the number of deaths
from botulism, but patients may still suffer nerve damage, and
recovery is often slow.
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29. Flexible packaging
• A retort pouch is commonly defined as a flexible
pouch for low-acid foods that are thermally processed
in a pressure vessel, often called a “retort.”
• The pouch is made of layered polyester, aluminum
foil, and polypropylene.
• Commercial sterilization occurs at temperatures
greater than 212 °F, typically 240 to 250 °F.
• The retort packaging is shelf stable at room
temperature.
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31. FIFO: First In First Out
• “First In, First Out is a system of monitoring food. It
also serves as your inventory control, expedites ordering
procedures and provides an efficient an effective order
and tracking system”.
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32. • Traditionally, the FIFO issue policy is used
when issuing perishable foods from frozen or
refrigerated storage.
• Implementation of the FIFO policy gives
highest issue priority to the oldest items within
a stockpile, while the LIFO policy gives
priority to the most recently processed items.
• FIFO – First In, First Out – as a best practice
for managing the quality and safety of food.
• FIFO is also a system that can be used to track
and manage the cost and financial value of
your inventory.
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33. Advantages of FIFO
1. To prevent foodborne illness and control commercial
kitchen costs.
2. ensure serving safe food and eliminates spoiled food
waste
3. Food moved is allocated from your records in a logical
and systematic manner.
4. Movement of food is continuous, orderly and
efficient.
5. Food easily identified as belonging to a particular lot.
6. It is a great tool for food safety.
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