In all fish, poultry and red meat processing industries the problem of Salmonella and Listeria bacteria represents one of the biggest challenges. Frequent use of water to rinse and remove dirt and debris from the product, the work stations, floors, and walls is essential. Yet, most water supplies are contaminated, or treated with chlorine. Large amounts of chlorine are needed to kill bacteria in a short time available on the process conveyors. Unfortunately, chlorine also reacts with the meat, forming highly toxic and carcinogen compounds called THMs or Tri-Halomethanes. The color of the meat surface may also be degraded by chlorine, potentially rendering a lesser quality product. This is especially concerning when the rinse water stays in pockets inside the meat product.

Ozone comes closest to the ideal solution. Ozone has been used in this application for almost a hundred years. For decades, chlorine seemed to be a cheaper alternative. Only about two decades ago, massive research into the byproducts of chlorine alerted the scientific world. It has been concluded that chlorine should ideally be eliminated not only from drinking water purification systems, but also from any application where organic materials are involved, and in the food processing industry in particular. Previously set dosages of chlorine are no longer effective on some viruses and parasites. For complete disinfection much higher dosages would have to be used, but such levels are not allowable to contact the meat.


  • Ozone is a tri-atomic oxygen molecule which loses one oxygen atom in the disinfection process to become a normal oxygen molecule. Oxygen is not toxic and it does not form toxic substances. Any excess of ozone breaks down into oxygen.
  • Ozone is by far more effective than chlorine in killing all bacteria, fungi and viruses, and it does this at a concentration 1/10 of that required by chlorine.
  • Ozone has a short reaction time and requires a shorter contact time than chemical disinfectants.
  • Ozone is a strong Oxidant and will eliminate odors as well as the micro-organisms causing the odors.
  • Ozone can be generated onsite from air and electricity, as a result the need for transporting and storing hazardous chemicals is eliminated.
  • The correct ozone level can be maintained electronically; there is no need for the manual preparation of washing solutions.
While in theory ozone has always appeared to be the perfect disinfectant, some practical challenges have prevented the full use of ozone much earlier in this century. The process requires that ozone gas be dissolved in the water first and any undissolved ozone gas removed and disposed of. Likewise, the maintenance of the ozone level in the water supply must be consistent all the time ? no matter what the actual water demand is at any given moment.

Over the past 20 years AZCO Industries has perfected a system to meet all of the above conditions ? in developing a fully automatic supply of Ozonated water for the meat processing industry. Each system is customized to the specific flow and needs of each specific operation, and consists of the following:

1. A FOOD GRADE STAINLESS STEEL TANK for ozone mixing, contact and off-gas. Mounted on the tank are:
Low and High water level sensors for automatic control of water supply, and for the protection of the pumps. Two stainless steel pumps. One for the ozonation circuit, and one for boosting the tank pressure to 3 atm (45 psi) as needed at the plant. Tank controller with solid state, zero crossing pump drivers and water supply automatic control. Ozone off-gas system.

Ozone generating modules to the full capacity required. Air dryer sized to the capacity required. Controller with the system power distribution, ozone level controller, dry air sensor, ambient air sensor, the tank controller interlock, and more ? for fully automatic operation and the safety of the whole system. The controller allows for the programming of the ozone level, so that the desired dissolved ozone concentration will be maintained automatically ? and independently of any momentary water demand. A warning light will indicate lower than acceptable conditions. The system can be wired to a central computer if desired.

The pipe distribution system includes manifolds for the ozonized water and allows proper distribution throughout the whole plant. A feedback to the contact tank is implemented to assure consistent levels of dissolved ozone in the distribution pipes when the water demand changes during the day.

The following are examples of the practical results achieved in various AZCO system installations:


In chicken processing plants it is common to hold the eviscerated birds in a chilled water bath for 1.5 hours. During this time the ozonation could be performed and the carcasses would be sterilized.