Evaluation of blended electrolyzed oxidizing water-based cleaning-in-place (CIP) technique using a laboratory-scale milking system

Milk safety is a food safety concern in the U.S., and the cleanliness of on-farm milking systems directly affects raw milk quality. The conventionally accepted four-step procedure for milking system cleaning-in-place (CIP) includes: (1) warm water rinse, (2) alkaline wash, (3) acid wash, and (4) sanitizing rinse prior to the next milking event. Electrolyzed oxidizing (EO) water is an emerging technology that generates acidic and alkaline EO water by electrodialysis of a dilute sodium chloride solution. Previous studies have shown that EO water can be an alternative for conventional milking system CIP, both in pilot-scale milking systems and on commercial dairy farms. Recently, a one-step cleaning process has been adopted on an increasing number of dairy farms that combines the alkaline wash and acid wash to save chemical expenditure, water usage, energy cost, and time. By blending acidic EO water with alkaline EO water, a less corrosive but still effective blended EO water solution can be produced. Therefore, this study was undertaken to evaluate the blended EO water solution for one-step CIP using a pilot-scale milking system and compare the CIP effectiveness and cost with commercial one-step CIP chemicals. A Box-Behnken three-factor response surface method was used to determine the optimal cleaning time, the starting temperature of the blended EO water solution, and the acidic EO water percentage. Two commercial one-step CIP chemicals were used for comparisons of CIP effectiveness and cost. Results showed that a cleaning time of 17 min, a starting temperature of 59 degrees C, and an acidic EO water percentage of 60% in the blended EO water solution could achieve the required 100% CIP performance and was comparable to the commercial one-step cleaning chemicals. Moreover, it was determined that the operating cost of one complete cleaning cycle, including the material cost and energy consumption, using blended EO water was 80% lower than using the commercial one-step cleaning chemicals. Overall, this study demonstrated that blended EO water has potential to be adapted as an alternative for one-step CIP for milking systems and possibility other food processing equipment.