Disinfection in Dairy Milking Parlours Using ECA: Anolyte & Catholyte

Introduction

Dairy products such as milk, butter, cream, and cheese are highly susceptible to microbial spoilage due to their chemical composition. Fresh, non-pasteurized milk contains various microorganisms, the numbers of which depend on milking, cleaning, and handling practices.

Common spoilage organisms in raw milk include molds, yeasts, and bacteria such as Enterococcus, Lactococcus, and Pseudomonas.

Pasteurization eliminates most bacteria, except for heat-resistant strains that can cause spoilage if conditions are favorable. A well-balanced cleaning and sanitizing program is crucial for producing high-quality raw milk, achieving microbiological standards often not met by pasteurized milk in many processing plants in South Africa.

Electro-Chemical Activation (ECA) Technology

ECA technology was recently introduced in South Africa as a novel method for water disinfection. This process involves passing a dilute saline solution through an electrolytic cell, producing two types of activated water: Anolyte and Catholyte.

Anolyte, with a pH range of 2-9 and an oxidation-reduction potential (ORP) of +400 mV to +1200 mV, acts as an oxidizing agent with antimicrobial properties. Catholyte, with a pH of 12-13 and an ORP of about -900 mV, has reducing and surfactant properties. The ECA process generates stable products (acids and bases), highly active unstable products (free radicals), and quasi-stable structures (complex hydrated membranes). These features enhance the diffusion, catalytic, and biocatalytic properties of the water.

Materials and Methods

The study analyzed three milking stations daily after disinfection. Four surfaces at each station were sampled: the inside of the teat cluster, teat cluster top, float control flow sensor inside, and float control flow sensor lid. Sterile swabs were used to sample these surfaces, and the samples were streaked on nutrient agar plates, incubated at 37°C for 48 hours, and the colonies were counted.

Sporeformers were detected by suspending colonies in sterile distilled water, incubating at 80°C for 10 minutes, and then plating on nutrient agar. The effectiveness of bulk tanker washing was tested by washing with the usual disinfectant and ECA solutions, sampling the surfaces with Rodac plates, and incubating at 37°C for 24 hours.

Results and Discussion

The results showed that conventional disinfectants had some degree of microorganism control, but many surfaces were not satisfactorily disinfected.

The Anolyte, however, eliminated spreaders and provided better disinfection, particularly for the float control flow sensor inside. The combination of Catholyte followed by Anolyte was effective for disinfecting the bulk tank, with most surfaces being sterilized.

The table below summarizes the microbiological analysis of different surfaces in a milking parlour after disinfection with conventional methods (Control) and Anolyte:

Conclusion

- Contact between disinfectant and surface is essential for effective disinfection.

- Anolyte effectively eliminated spore-forming bacteria.

- Anolyte provided better overall disinfection compared to conventional disinfectants.

- The combination of Catholyte followed by Anolyte was effective for bulk tank disinfection.

References

- Jay J. M. (1992). Modern Food Microbiology. 4th edition. Chapman & Hall, New York. ISBN 0-442-00733-7.

Note: This white paper provides a comprehensive overview of the study conducted on the disinfection efficacy of Anolyte in dairy milking parlours. The information is based on research by Prof T E Cloete and M S Thantsha from the University of Pretoria, South Africa, and includes detailed experimental methods, results, and conclusions to demonstrate the effectiveness of Anolyte as a disinfectant.

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