Milk is known as "liquid gold" because it is rich in nutrients, but these nutrients also provide a good environment for the growth of microorganisms in the milking system. If the milk storage equipment is not properly cleaned, the growth of microorganisms will form a biofilm on its surface, causing serious contamination to the next batch of raw milk stored . In the milking system, the traditional CIP process usually includes 4 steps:
1) Rinse with warm water at 38-55℃;
- Cleaning with alkaline or acidic detergent;
- Rinse with warm water at 38-55℃;
- Rinse with disinfectant or 90-95 ℃ hot water before the next milking.
The detergent stock solution used by dairy farms to clean the milking system is a highly concentrated liquid with strong alkali or strong acid. Long-term use of strong alkali or strong acid in the milking system will accelerate the corrosion of equipment, reduce the service life of the machine, and increase the operating cost of the dairy farm. If the washing wastewater is discharged without qualified treatment, long-term accumulation and penetration in the farmland will cause immeasurable harm to the environment. Detergent residues in raw milk will seriously affect the quality of dairy products and the reputation of the dairy farm, resulting in heavy economic losses . In addition, strong acid or strong alkaline detergents are highly corrosive to the skin and mucous membranes, and will threaten the staff if they are not properly operated during the dilution process.
Approximately 1,000,000 children are harmed each year in the United States by exposure to improperly stored chemicals. Therefore, it is imperative to use less polluting, less hazardous, and less expensive detergents in milking systems.
The research on the sterilization effect and cleaning mode of hypochlorous acid electrolyzed water for milk storage tanks can be analyzed from the following aspects:
Cleaning and sterilization effect of electrolyzed water
Studies have shown that both alkaline electrolyzed water(NAOH) and slightly acidic electrolyzed water(HOCL) can be effectively used for cleaning and disinfecting milk storage tanks. For example, when cleaning milk storage tanks, the removal rates of bacteria and ATP by alkaline electrolyzed water (pH 12) and hypochlorous acid water (effective chlorine concentration of 60 mg/L) reach or exceed the effects of traditional commercial cleaning agents. In addition, the bactericidal mechanism of electrolyzed water mainly depends on its pH value, effective chlorine concentration and redox potential, which work together on the cell membrane and enzyme system of microorganisms to achieve efficient bactericidal effects.
Optimization of cleaning mode
Among different cleaning modes, the electrolyzed water cleaning mode of one alkali and one acid is recommended as the best choice. This mode uses alkaline and acidic electrolyzed water alternately to more effectively remove bacteria and residue from the milk storage tank. Experiments show that this model not only improves cleaning efficiency, but also reduces economic costs, saving production water and operating costs.
Environmental protection and economic advantages
As an environmentally friendly cleaning agent, HOCL water is non-toxic, non-corrosive and can be discharged directly after use, complying with environmental protection policies. Compared with traditional strong acid and alkaline chemical cleaning agents, electrolyzed water not only reduces equipment corrosion and wastewater treatment costs, but also significantly reduces production costs and water consumption.
Application prospects and safety
The application of electrolyzed water in the food industry has been widely recognized, and relevant standards are constantly being improved. For example, GB 28234-2020 "Hygiene Requirements for Acidic Electrolyzed Water Generators" clarifies its application scope and safety in the food industry. In addition, the use of hypochlorous acid electrolyzed water has been proven to be harmless to the health of workers and can effectively inhibit the reproduction of microorganisms.
Using hypochlorous acid electrolyzed water to clean and sterilize milk tanks is an efficient, environmentally friendly and economical solution. By optimizing the cleaning mode (such as one alkali and one acid mode), the cleaning effect can be further improved while meeting the high standards of hygiene and safety in the food industry.
The comparative study on the effect of electrolyzed water with different pH values and effective chlorine concentrations in milk tank cleaning mainly involves the following contents:
Cleaning effects of alkaline electrolyzed water and slightly acidic electrolyzed water:
The study showed that alkaline electrolyzed water (pH 12) and slightly acidic electrolyzed water (effective chlorine concentration 60 mg/L) showed different effects when cleaning milk storage tanks. The cleaning time of alkaline electrolyzed water was 8 minutes and the temperature was 70.3°C, while the cleaning time of slightly acidic electrolyzed water was 9.9 minutes and the temperature was 37.8°C.
Another study pointed out that using slightly acidic electrolyzed water with a pH of 11.3 and slightly acidic electrolyzed water with a pH of 2.6 and an effective chlorine concentration of 50-80 ppm to clean milking pipes at 60°C for 7.5 minutes can completely remove bacteria and ATP from the inner surface of the pipes, and its cleaning effect is equivalent to that of traditional cleaning processes.
Sterilization effect and stability of electrolyzed water:
Slightly acidic electrolyzed water (pH 5.0-6.5, effective chlorine concentration 10-30 mg/L) showed good bactericidal effect under different storage conditions. In light-proof and airtight conditions, the two electrolyzed waters were relatively stable and maintained good bactericidal effect after 7 days.
During storage, the pH of slightly acidic electrolyzed water will increase, while the available chlorine concentration and oxidation-reduction potential (ORP) will decrease. For example, after 12 days of storage in a transparent bottle at 25°C, the ACC of slightly acidic electrolyzed water dropped from 20.53 mg/L to 5.06 mg/L, and the ORP dropped from 821 mv to 641 mv, while the pH value increased from 6.06 to 7.45.
What are the specific comparative data in terms of economic cost and environmental impact between the one-alkali-one-acid electrolyzed water cleaning mode and traditional cleaning methods?
Economic cost:
The electrolyzed water cleaning mode can significantly reduce production costs. For example, in dairy industry CIP cleaning, the cleaning mode using electrolyzed water, alkali and acid can save 74% of production costs compared with commercial cleaning agents.
Environmental impact:
The electrolyzed water cleaning mode puts less burden on the environment. For example, electrolyzed water equipment shows high intelligence and high quality in the field of industrial cleaning. It is suitable for a variety of scenarios, including metal parts cleaning, precision cleaning, fruit and vegetable cleaning, etc., and meets environmental protection standards.
The electrolyzed water cleaning system uses alkaline electrolyzed ionized water produced by electrolyzing water as the cleaning fluid to minimize chemical damage to the cleaning object materials and only removes attached components, such as processing oil and other dirt, which is friendly to the environment and the cleaning objects.
The one-alkali-one-acid electrolyzed water cleaning mode has significant advantages in economic costs and can significantly reduce production costs and operating costs;
In the food industry, hypochlorous acid electrolyzed water ( HOCL/EW ), as an emerging green and environmentally friendly detergent, has been practically used in the cleaning and disinfection of the dairy industry. The following are several specific application cases and effect feedback:
Penn State Research:
In 2005, Walker et al. from Pennsylvania State University studied the cleaning effect of electrolyzed water on a milking pipe model. They found that using electrolyzed water to clean milking pipes for 7.5 minutes can completely remove bacteria and ATP on the inner surface of the pipes, and the cleaning effect is comparable to that of traditional disinfectants (such as phosphoric acid and nitric acid), but there is no corrosion damage to the milking pipes.
Research at China Agricultural University:
In 2017, Liu Yu and others from China Agricultural University conducted an experiment on cleaning 100L vertical milk storage tanks with electrolyzed water. The experimental results showed that the electrolyzed water cleaning mode has a good cleaning effect and can save 74% of production costs and 33% of production water compared with commercial cleaning agents.
The preparation of electrolyzed water can be achieved by using the electrolyzed water generator produced by BLUEWAV, which has automatic integrated control, 24-hour continuous operation, flexible and convenient operation, easy installation (skid-mounted), long equipment life, low salt consumption, low power consumption, and can produce food-grade and medical-grade hypochlorous acid water (anolyte) and a small proportion of sodium hydroxide solution (cathode output) through diaphragm electrolysis technology. The PH of hypochlorous acid solution is adjustable from 3 to 7, and the PH of sodium hydroxide solution is adjustable. Help you improve your efficiency and provide you with customized solutions!
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