The other aspect is to dissolve ozone in water and use the ozonised water for washing the foods to eliminate surface contamination. Ozonised water can also be used in the process as well in place of regular water for better hygiene control. This keeps the foods sterile while under process. In some instances, gaseous ozone at very low concentration is applied directly to the foods being processed to sterilise it. Ozonised water is also used for washing of equipment during COP to sterilise work surfaces, floors and walls in the processing room. Personnel handling the foods also use ozonised water for washing hands. Ozone is applied at various points during the processing till the foods are packaged. In some instances, even the packaging used in the process is sterilised using ozone.
Besides the processing part, food processing industry generates a huge quantity of biological waste which forms a part of the liquid waste in addition to the solid waste. It is mandatory to treat this waste before disposing off. While solid waste can be treated in incinerators, the liquid waste, which is mainly water containing the solid particulates, requires to be taken care with a properly designed waste water treatment plant. Since it contains a good quantity of biodegradable material, it requires a good combination of oxidation treatment in more or less the same way sewage water is treated. After the primary treatment of removal of solids from the waste water, the water is ozonised to break down the bio-organics which become easy to digest in the bioreactors. The second stage of ozone application is the tertiary treatment for disinfection. The water treated with two stage ozonation can help in realising the water for recycling. This can save water as well. Ozone also offers the advantage of reduction of odour from the water while improving on the colour due to bleaching action of ozone in water. Additionally ozone helps in reduction of BOD (biological oxygen demand) and COD (chemical oxygen demand). However, the primary function of using ozone in the tertiary treatment is to disinfect.