Ozone Contribution in the Food Industry October 24 2017, 0 Comments

Japan has emerged as a global leader for the use of ozone in the food industry.

A 2006 study attributed this success to the achievements of modern ozone generators that are capable of outputting high concentrations of ozone while still remaining energy efficient in its power consumption.

At the right concentrations, ozone is one of the strongest sanitizers available on the market today. The researchers attribute this potency to the unique properties of ozone. Once in contact with bacteria, ozone rips open the cell wall from the outside, causing the cell contents to fall apart. Once inside the cell, ozone destroys the DNA of the organism. This oxidizing power is able to prevent bacteria from developing a resistance to ozone as its contents are totally eradicated leaving nothing behind.

Ozone is best utilized in the Japanese food industry in two ways. Treatment plants have the option of using ozone gas or ozonated water. The study argues ozonated water is more efficient because it is easier to contain. Ozone gas has a short half-life of around 30 minutes, meaning it cannot be stored.

Fruits & Vegetables

The researchers tested the effects of ozonated water on a plethora of fruits and vegetables. The test was performed on carrot, cabbage, lettuce, apple, orange, grape, Chinese gooseberry, Japanese persimmon, Japanese radish, cucumber, spinach, bean sprout, parsley, melon, burdock, and potato. 0.5 to 5.0mg/L of ozonated water was used on the produce for an extended period. The study found the water treatment extended the shelf-life of all produce tested.

“The influence of ozone modified-atmosphere packaging, storage temperature, and time on survival ratio and growth of microorganisms were determined for shredded lettuce, grape, strawberry, sliced cucumber, shredded Japanese radish, and shredded carrot.”

Controlled atmosphere packaging is used around the world to maintain freshness in produce and prevent the ripening process in many different varieties of fruits and vegetables. Ozone was included in the controlled environments to further increase the shelf-life of produce tested.

Fish & Processed Marine Products

Ozone is known to increase the shelf-life of fish, as we have previously reported on this blog. In this study, ozonated water was used to disinfect and to improve sensory qualities for fish and fish products.

For researchers, the impact of ozonated water treatment was obvious, “The storage life of the above fishery increased 50% to 80% when the ozonated water treatment was applied only once.” The use of ozone gas also accelerated depuration, which is a process commonly used in Japan to purge certain types of seafoods of contaminants and impurities. The study concluded that the use of ozone in the cleaning process was able to curb the growth of some bacteria that are known to attack fish products. Some of these included: Micrococcus varians, M. caseolyticus, M. colpogenes.

Cereals & Cereal Products

Keeping cereal products free of bacteria is key. According to the study, numbers of bacteria vary widely from few hundred per gram to thousands. Breads can be exposed to bacteria from the air while cooling and/or while wrapping the item.

“The surface of a freshly baked loaf of bread is practically free of viable microorganisms but is subject to contamination by mold spores from the air during cooling and before wrapping. During slicing, contamination may take place from microorganisms in the air, on the knives, or on the wrapper,” the study said.

Utilizing ozone for these product types had its own set of benefits. “Combination treatment by alternately applying ozone treatment and UV irradiation reduced the contact time for inactivation of Bacillus and Clostridium spores,” the study said.

"The survival ratio of M. suaverolens was found to decrease with increasing dissolved ozone concentration ranging from 1 to 15mg/l and all mold cells were completely killed with ozonated water containing 15mg/L dissolved ozone at 25C for 5 minutes."

Confectionery Products

In this study, researchers examined the impact of ozone treatment on sugar confectionery products and chocolate confectionery products. For both categories of confectionery products, mold is the most common form of spoilage. 

Bacteria impact confectionery products differently because they contain different ingredients. Roping, which is a germ disease, can impact cake. "The spores of these species can withstand the temperature of cake during baking, which does not exceed 100 degrees Celsius or contaminated during cooling and can germinate and grow in the loaf if conditions are favorable."

Confectionery products could develop a musty odor or a soapy taste due to the growth of mold. Because some forms of mold are resistant to heat, another process should be applied to the products in order to remove the contaminants. These microorganisms were easily sterilized by 1–10 mg/L ozonated water for 100–300 s at 5 degrees Celsius.

Meat & Meat Products

Autolysis is used on meat products to kill yeast. However, excessive autolysis can negatively impact the quality of the meat product by giving it a souring taste. 

"It has been pointed out that during slaughter, dressing, and cutting, microorganisms come chiefly from the exterior of the animal and its intestinal tract but more are added from knives, cloths, air, workers, carts, boxes, and equipment in general," the study said.

"It it can be assumed that under ordinary conditions most kinds of potential spoilage organisms are present and will be able to grow if favorable conditions present themselves," the study said. 

To test the impact of ozone treatment, the researchers examined the bacteria levels on smoked chicken, "Ozone also can be applied for preventing secondary contamination during smoked chicken roll manufacturing." Overall, the addition of ozonated water to the manufacturing process had a positive impact on the quality of the product. "The microorganisms isolated from spoiled smoked chicken roll were exposed to 0.3–0.8 ppm ozone for 1–4 h. These bacteria were reduced."

Processing Plants

Additionally, researchers studied the impact of the use of ozone in processing plants that handle the food products. One major concern for these type of plants is eliminating contaminants to ensure food products are not impacted. "Ozone gas and ozonated water was effective and reproducible in its effect on airborne microorganisms," the study said.

A noodle manufacturing plant was studied to test the effect of ozone on the overall quality of the product. The plant was exposed "to 0.05–0.18 ppm ozone for 5–6 hours per day and 1 year." This amount of ozone treatment  "Aerial contaminants such as Lactobacillus fructivorans, which cause swelling phenomenon of product, Japanese Row Noodle processes were reduced."

Natto, a traditional Japanese food item, was ozone treated as well. A certain amount of bacteria is used by the soy product to create fermentation that is critical to the ripening process. However, some natto products can be polluted by bacteriophages. "the status of natto plant pollution by bacteriophages, which cause mucilage formation of natto throughout Japan, is one of the most crucial topics today," the study said.

The researchers found a useful way natto plants can utilize ozone to prevent contamination. An interior floor in a natto factory was sprayed with 0.5 to 1.0 mg/L ozonated water for 30 minutes per day for 3 months. Researchers discovered that, “Floor contamination such as natto bacteriophage in the natto proceses was eliminated." 


The study concluded, “Ozone is effective as a potent sanitizer in the food industry for vegetables, fruits, fish and processing marine products, cereal and cereal products, confectionery products, meat and meat products, processing plants.”

The degree of success for each product type varied with the ozone concentration and time the items were exposed to the ozonated water. The application of ozone to many different industries in Japan demonstrates the diverse industries that can harness the naturally occurring properties of ozone.

Ozone is used in a variety of industries daily. Learn about how one of nature's most extraordinary marvels is used in the dairy industry and aquaculture.

A2Z is pleased to create and manufacture units specifically scaled with these applications in mind.  Long-term use, high ozone concentration output with the option for continuous use, and custom build units are just a few of the options we offer for clients. For more information about a specific lab or industrial unit, please contact us at (502)499-4977 or email us at info@a2zozone.com



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