Application of ozone for enhancing the microbiological safety and quality of foods: A review

Ozone (O-3) is a strong antimicrobial agent with numerous potential applica tions in the food industry. High reactivity, penetrability, and spontaneous decomposition to a nontoxic product (i.e., O-2) make ozone a viable disinf ectant for ensuring the microbiological safety of food products. Ozone has been used for decades in many countries and recently, the generally recogni zed as safe (GRAS) status of this gas has been reaffirmed in the United Sta tes. Ozone, in the gaseous or aqueous phases, is effective against the majo rity of microorganisms tested by numerous research groups. Relatively low c oncentrations of ozone and shea contact time are sufficient to inactivate b acteria, molds, yeasts, parasites, and viruses. However, rates of inactivat ion are greater in ozone demand-free systems than when the medium contains oxidizable organic substances. Susceptibility of microorganisms to ozone al so varies with the physiological state of the culture, pH of the medium, te mperature, humidity, and presence of additives (e.g., acids, surfactants, a nd sugars). Ozone applications in the food industry are mostly related to d econtamination of product surface and water treatment. Ozone has been used with mixed success to inactivate contaminant microflora on meat, poultry, e ggs, fish, fruits, vegetables, and dry foods. The gas also is useful in det oxification and elimination of mycotoxins and pesticide residues from some agricultural products. Excessive use of ozone, however may cause oxidation of some ingredients on food surface. This usually results in discoloration and deterioration of food flavor. Additional research is needed to elucidat e the kinetics and mechanisms of microbial inactivation by ozone and to opt imize its use in food applications.