The safety of fruits, vegetables, salads, and other ready-to-eat foods has become a concern among consumers and regulators. Chemical contaminants and pathogens are among the main concerns. The wash water for salads is sometimes disinfected with chlorine in the U.S. If chlorine is used, the product can become contaminated with chlorinated chemicals. In fact, chlorinated fruit and vegetable sanitization is restricted by the European Union because of this. Ozone generators are being installed in many European packaging companies as a disinfection method.
Benefits of Ozone for Fruit & Vegetable Sanitization
Chlorine, chlorine dioxide, or peracetic acid are not as powerful disinfectants as ozone. Fruits and vegetables can be sanitized with ozone, which has many benefits over chlorine. In addition to bacteria, viruses, cryptosporidium, giardia, etc. It is effective against a wide range of other pathogens as well. Moreover, ozone has a relatively short lifespan in water, lasting only 10 to 20 minutes before deteriorating to oxygen. Consequently, it does not produce harmful byproducts like chlorine or chlorine dioxide. The fruits and vegetables are thus protected from contamination by disinfectant byproducts, and the used washing water is easily discharged.
Application of Ozonated Water
Washing fruits and vegetables with ozonated water includes washing RTE salads. Ozone can be enhanced by filtration in conjunction with ozone. In order to maintain a relatively constant concentration of ozone, a side stream from the flume is injected with ozone.
Some situations require residual concentrations of disinfectant, which can be achieved by adding chlorine. Using chlorine as the principal disinfectant will result in a substantially lower chlorine requirement under these circumstances.
To ensure that the side stream is properly mixed with the bulk flume flow of water, a diffuser will be necessary to reduce ozone concentrations in the side stream. The water from the flume is sometimes continually recirculated through the ozone unit, which absorbs the ozone gas prior to returning to the wash tank.
To maximize ozone transfer efficiency into water, the system should be engineered to maximize ozone transfer efficiency. Additionally, the system should enable the water to be degassed and decomposed before entering the general environment or the work area.
The concentration of Ozone used during flume washing applications has ranged from .05 to .15 ppm, while the concentration of 1 to 3 ppm has been used for spray washing applications.
There is a variation in ozone concentration during spraying processes. Injecting ozone gas into the water might result in a dose of 3 ppm. In the pressurized line, the ozone concentration will usually be between 1.5 and 2.0 ppm, given a 3-ppm applied dose. This is because the ozone transfer efficiency is never 100%. As the pressure decreases to the atmosphere, the ozone is not transferred. Ozone will eventually come out of solution at lower pressure. Food surfaces may have a water content of 0.5-1.0 ppm.
Food borne pathogens are controlled and food taste and appearance are improved. There is evidence to support this claim. Reduced bacteria count reduces the risk of food spoilage and increase the shelf life of foods.
Ozonation can reduce water requirements by utilizing less water and supporting water recycling. When paired with filtration, ozonation can prolong the time during which water can be used before it must be discharged. Because ozone is a powerful disinfectant as well as an excellent oxidizer of organic contaminants in flume water. Additionally, ozone allows for better filtration due to its micro flocculent activity.
Chlorine leaves behind chlorinated byproducts whereas ozone does not. Food residues from these byproducts are regulated by European regulations. NPDES permits restrict the discharge of chlorinated byproducts as well.
Food is biodegradable because pesticides as well as other chemicals are broken down as a result of ozone’s chemical oxidizing action.
What Are the Problems Associated with Fruits and Vegetables?
Bacteria, pathogens, and spoilage microorganisms are present on the surface of food products and are capable of growing very quickly, affecting the freshness and shelf life of vegetable and fruit products.
In addition, a significant number of residues of pesticides and insecticides is present on the surface of the food product, which is not only dangerous but also objectionable in terms of standards.
What Is the Present Practice?
Most washing water is disinfected by adding chlorine and other chemicals. By using chemicals to wash clothes, the by-products are harmful, e.g., chloramines, trihalomethanes etc. These substances are not only undesirable, but they are also banned in some cases and are being phased out rapidly.
How to Control Microbial Counts with Ozonated Water?
It is a powerful antimicrobial agent well-suited for broad-spectrum control of microbes, and it is also a very effective disinfectant. Using strong Ozonated water for washing vegetables will not only reduce the microbial load on the surface but also destroy all bacteria, viruses, cysts, and pathogens on the surface of the vegetables.
Long-chain organic substances such as pesticides are oxidized to short-chain organic compounds, which in turn decompose into harmless substances. In conclusion, washing vegetables and fruits with Ozonated water or heavily disinfected water will make them fresher for longer shelf life, and organically safe.
Ozonated water is among the best available and most advanced technologies today for washing fruits and vegetables, disinfecting and cleaning buildings, and many other applications.
Ozone Concentration in Water Treatment
Using Ozonated washing water will clean vegetables or commodities sufficiently to prevent the spread of bacteria. The concentration of ozone in the wash water in such an application should be relatively high, in the range of 0.2 to 1.0 ppm. How much ozone is required will depend on how critical the application is.
How Much Ozone Required?
There are several factors affecting how much Ozone should be dosed into wash water, including: flow rate, composition of water, technique of dissolution of Ozone, product being washed, water temperature, initial contamination with bacteria, and microbiological quality of the washed product. Generally, computer programs are used to estimate the flow rate of Ozone.