Ozonation has been used for years to disinfect water for drinking purposes in Europe. A number of other commercial uses have been found for ozone including disinfection of bottled water, swimming pools, prevention of fouling of cooling towers, and wastewater treatment.

Ozone is one the most powerful antimicrobial substance (natural sanitizing and disinfecting agents) in the world destroying up to 99.999% of microorganisms commonly found on food due to its potential oxidizing capacity. Any pathogen or contaminant that can be disinfected, altered or removed via an oxidation process will be affected by ozone. It is the strongest of all molecules available for disinfection.

Ozone use may have many advantages in the food industry. There are suggested applications of ozone in the food industry such as food surface hygiene, sanitation of food plant equipment, reuse of waste water, lowering biological oxygen demand (BOD) and chemical oxygen demand (COD) of food plant waste.

In the United States, ozone has received in 1997 GRAS (Generally Recognized as Safe) classification, and in 2001 the FDA officially approved media containing ozone for use in the food industry, also for direct contact with food products, including fish, meat and poultry.

Ozone (O2) is an allotropic form of oxygen (O2), i.e., it is made up of same atoms, but they are combined in different form. The difference is the presence of three oxygen atoms, whereas “common oxygen” has only two. It has low molecular weight (MW=48) whose three oxygen atoms chemically are arranged in chain. Ozone is then enriched oxygen (O3).

Ozone is one of the oxidants more powerful than they are known, and for this reason it has a strong capacity of disinfection. Their disinfectants properties are superior: it is a powerful germicide which destroys all class of bacteria and fungi, not allowing their development. While undergoing reaction, ozone reverts to oxygen making it the most environmentally friendly disinfectant.

Unlike other biocides agents such as chlorine, the time necessary to make the disinfection is much less. For this reason, it’s very effective in destruction of chlorine resistant microorganisms due to a power of reaction of three thousand times superior to the chlorine.  

Until now, chlorine has been the sanitizer of choice in the food processing industry. But experts share a growing concern about dangerous by-products (such as trihalomethanes or dioxins) that are produced when chlorine reacts with the organic matter found in water. These by-products are known carcinogens and when found in drinking water; their levels are strictly regulated by the U.S. environmental Protection Agency – EPA.

The opposite is true for ozone. When ozone reacts with organic matter, it does not form any toxic by-products. Ozone technology has several significant advantages over its chemical alternatives as follows

1. Ozone can be generated on-site;
2. Ozone is one of the most active, readily available oxidizing agents;
3. Ozone rapidly decomposes to oxygen leaving no traces;
4. Reactions do not produce toxic halogenated compounds;
5. Ozone acts more rapidly, and more completely than other common disinfecting agents do;
6. Ozone reacts swiftly and effectively on all strains of viruses.

• 1906 – Ozone used to provide safe drinking water in Nice, France;
• 1910 – First use of ozone in a German meat packing plant;
• 1918 – Ozone used to sanitize swimming pools in the United States;
• 1936 – Ozone used to treat shellfish in France;
• 1942 – Ozone used in egg storage rooms and in cheese storage facilities in the United States;
• 1972 – Ozone used to purify process water in Germany;
• 1977 – Ozone used to reduce Salmonella in shell eggs in Russia;
• 1982 – Ozone declared GRAS (Generally Recognized as Safe) for bottled water in the United States – Reaffirmed Gras in 1995;
• 1997 – Expert Panel convened by EPRI declared ozone GRAS in food processing in the United States;
• 2000 – Food additive Petition filed with the FDA, August 15, 2000;
• 2001 – FDA recognizes ozone as a secondary direct food additive to kill foodborne pathogens. This approval opened the floodgates for food processors to begin utilizing ozone in their plants. FDA officially approved media containing ozone for use in the food industry, also for direct contact with food products, including fish, meat and poultry (Federal Register, Vol. 66, no. 123, Tuesday, June 26, 2000. Rules and Regulations);
• 2001 – Food Safety and Inspection Service (FSIS) declares acceptable in poultry and meat products.

Today, the use of ozone is steadily replacing conventional sanitation techniques such as chlorine, steam or hot water. It’s gaining momentum in the food processing industry as the safest, most cost-effective and chemical-free way of dealing with food safety management.

The use of ozone dissolved in water for applications such as sanitizing food, drinking water purification, and surfaces disinfection provides numerous cost, environmental and liability advantages. Ozonated water removes pesticide and other harmful chemical residues from water, fruits and vegetables. In addition, it removes odors. Even at low concentrations, ozonated water kills most viruses, bacteria, parasites, mold and other microorganisms. After disinfection, ozone leaves nothing but oxygen, which makes it much safer and environmentally friendly versus traditional chemical treatments.

• In the United States, the FDA has approved the use of ozone like antimicrobial agent for the direct contact with all foods and food products (June 26th, 2001)
• The Ministry of Agriculture of the United States approved it like antimicrobial agent for the direct contact with meats, poultry, fish, mollusks and crustaceans (December, 2011)
• The government of Japan in 1996 admitted its use for the direct contact with all types of food. Ozone appears in a similar list of FDA as “Generally Recognized as Safe” (GRAS). The Japanese boats of fishing use ozonized water routinely to wash the fresh fish, to make the ice with ozonized water and to pack it on board.
• The Canadian Food Inspection Agency (CFIA) has approved the use of zone for the cleaning of the contact surfaces of food.
• The government of Australia (also in 1996) authorized the use of zone for the contact with all foods – similar to the Japanese approval.
• Permitted under Soil Association (UK) standards of use for direct contact on organic produce.

Reference: Alex Augusto Gonçlaves
                   Center of Water Resources Studies; Department of Civil & Resource Engineering;
                   Dalhousie University; Halifax; NS; B3J 1Z1; Canada