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Ozone and Food Storage

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Cold storage rooms hold various types of foods including vegetables, fruits, meats, sea foods, etc. The temperatures vary from low cool to way below freezing. All food products, being highly degradable, start breeding bacteria. At low temperatures, bacterial activity is slowed down, bacteria may be inactivated, but not destroyed. Atmospheric bacteria anchor on the surfaces of foods and attack them releasing acids which slowly spreads further inside decaying the food. At low temperatures, this process is slowed down. Controlling or destroying these bacteria helps in maintaining the foods fresher for far longer. Using disinfectants helps in controlling the bacterial activity, but the disinfectant used should not become a part of the food when consumed. Ozone has been found to be of tremendous advantage in such cold storage rooms for better maintenance of stored foods.

Injecting ozone in the air inside the cold storage rooms maintains the environment inside bacteria free. As a result the bacterial activity on the surfaces of foods under storage is minimal. It has also been found that vegetables, fruits, meats, sea foods, even eggs washed in ozonised water increases the shelf life of these products. This is because ozone destroys the surface bacteria which are present on all the foods, thus reducing the bacterial activity on the surfaces of the foods. This further helps in reducing the decaying process while increasing the shelf life. The same principle holds good in applying ozone in the environment inside the cold storage rooms. The foods store fresher and longer with ozone than without it inside the cold storage rooms. The safe factor is that since ozone has a very short half life, there is no toxicity either in the foods nor in the environment.

Ozone Helps Produce Last Longer by Extending Shelf Life

Common Applications for Ozone use in Food Storage

  • Potato Storage Facilities
  • Onion Storage Facilities
  • Citrus Fruit Storage
  • Vegetable Storage
  • Aged Ham Storage
  • Cool Meat Storage
  • Preservation of Fish and Seafood
  • General Cold Storage Facilities

 

Benefits of Ozone Use in Cold Storage

(and why at normal temperature it is essential)

  • Extend shelf-life of the produce within the cold storage facility.
  • Air-borne microbiological control
    • Low ozone levels (<0.3 PPM) will inhibit microbiological growth in the air.
    • High ozone levels can be used for disinfection when room is empty.
  • Surface sanitation can be maintained
    • By inhibiting microbiological growth pathogens on the surface of produce, containers, and walls will be kept to a minimum.
  • Eliminate mold growth from cold storage area.
  • Odor control
    • Maintain an odor-free cold storage area
    • Keep odors from cross contaminating between products
  • Ethylene Removal

Extension of Storage Life With Ozone

Ozone has been demonstrated to improve the shelf-life of many foods.

Food

Extension

Storage Conditions

Fish

50-80%

ozone sterilized ice

Salmon

50%

ozone sterilized ice

Jack Mackerel and Shimaaji (fish)

1.2 - 1.6 days

Soak in 30% NaCl cont. 0.6 mg/L O3 30-60 min. every 2 days.

Beef (frozen)

30-40%

0.4oC; 85-90% RH; 10-20 mg/m3 O3, provided original microbial count is below 103/cm2

Poultry

2.4 days

Soak in ice water while passing in O3 (3.88 mg/L) 20 min.

Bananas

substantial

A few ppm O3 @ 12oC, if fruit is not within a few days of its period of rapid ripening.

Strawberries, Raspberries, Currents, Grapes

100%

2-3 ppm O3, continuously or several hours each day.

Apples

several

1.95 cm3 O3/m3

Potatoes

6 months

3 mg/L O3; 6-14oC; 93-97% RH

Eggs

8 months

0.6 ppm O3; 31oF; 90% RH

Cheeses

63 days

0.2 - 0.3 ppm O3

* Source: Review of the Applications of Ozone for Increasing Storage Times of Perishable Foods, Ozone: Science and Engineering, Vol. 4, pp. 147-163, 1982, Pergamon Press Ltd.

Ozone is Allowed for Direct Contact with Food

  • August 13, 1999 - FDA issues 21CFR Part 173.368 giving ozone GRAS approval for use on all meat and poultry products.
  • December 23, 1999 - FSIS published final rule approving the use of ozone in meat and poultry products.
  • December 17, 2002 - USDA issues FSIS Directive 7120.1 naming ozone a Safe and Suitable Ingredient Used in the Production of Meat and Poultry Products

Ozone and the USDA and FDA

Ozone is Approved for Use with Food.

The USDA and FDA have approved ozone as an antimicrobial agent for use with food processing. With regulatory approval, ozone has become a great option for cost-effectively disinfecting food.

Important Factors in Ozone Storage

Human Safety
Human safety must be factored in to ensure ozone levels are below safe levels when workers are in the area.

Concentrations
Different produce, meats and seafood will require different ozone concentrators to achieve effective preservation.

Ethylene
Many fruits and vegetables release ethylene, this gas accelerates the ripening process. Ozone rapidly oxidized ethylene.

Humidity
Food storage facilities are commonly higher humidity areas. Ozone is rapidly decomposed in high humidity areas. Ozone must be rapidly distributed throughout the area. However, humidity can be used to destroy ozone quickly, allowing employees to return to an area after the ozone introduction has ceased.

Circulation
Food to be stored in ozonized atmospheres should be packed to allow circulation of the ozone and air.

Mold
High humidity levels will make mold and most bacteria more susceptible to ozone. Ozone control of mold and spores is best conducted in relative high humidity areas.


Washing of Vegetables and meat
The other aspect is to dissolve ozone in water and use the ozonised water for washing the foods to eliminate surface contamination. An ozonizer is a type of air or water purifier which uses ozone to kill bacteria, mold and yeast on food or on contact surfaces, kill insects in stored grain, scrub yeast and mold spores from the air in food storage areas. Ozone oxidizes pesticides (hydrocarbons) so that they are no longer toxic or harmful chemicals.
It is a known fact due to demands for increased production from limited land resources and powered by the ‘success’ of bio technology, we are now cultivating much than before using more pesticides and chemical fertilizers. These chemicals eventually come back to us with the vegetables and in some cases (remember the European episode – only two months back) bacteria still reside in the green vegetables causing fatal fallout. For this, the vegetables are essentially required to be soaked in concentrated ozone water mixture and then washed by the same mixture thoroughly to get rid of entire stretch of microbial contaminations.

Therefore…

  • Ozone should be there in the air to sterilize the air inside storage room and thus to increase shelf life of food, besides keeping them fresh

Ozone should be used to disinfect the vegetables (and meat to prevent contamination from animal virus) by washing and for removing pesticides and residue of chemical fertilizers.