Milk Safety Improvements for Milking Equipment and Raw Milk Production

NON-TECHNICAL SUMMARY: Milking systems are commonly cleaned with a three-step CIP process: A warm water rinse, washing with a highly alkaline solution, and then rinsing with acidic solution followed by sanitizer rinse. The chemicals used in cleaning milking systems are costly and also handled and stored on the farm in concentrated form. Both the concentrated alkaline cleaner and acid can cause serious burns of the skin and eyes on contact. They may not be environmentally friendly. Electrolyzed oxidizing (EO) water is a novel cleaning and sanitizing agent. EO water is produced via electrolysis of a weak salt solution into sodium and chlorine, using a membrane between the electrodes to help with the separation of the ions from each other, yielding an alkaline solution and an acidic solution. Therefore, it can fit easily into the accepted three-step washing process for CIP cleaning of milking systems. Moreover, preliminary studies suggested that temperature of EO water can be reduced to 60oC without compromising the outcome. Chemicals used for cleaning are expensive and represent an operating expense for the dairy producer. Once the initial investment is made to purchase a machine to make EO water, the only operating expenses are water, sodium chloride, and electricity. This is an economical gain for dairy farmer and milk producers Pennsylvania and the U.S. The sale of raw milk, which is legal in a number of states, has been increasing, and will likely continue to increase in the foreseeable future, and disease outbreaks attributed to the consumption of raw milk (and raw milk products) have been well-documented. This trend of increasing sales could potentially result in an increased probability and magnitude of disease outbreaks in consumers. However, it is not known if the prevalence, incidence and epidemiology of potentially harmful pathogens are the same on legal raw-milk operations as in herds that produce milk strictly for the pasteurized market. Therefore, a comprehensive risk assessment of this emerging issue should be undertaken, so that effective interventions might be recommended to improve the safety of raw milk, and to minimize any negative public health consequences. In the United States, widespread use of pasteurization began in 1938. Outbreaks associated with the consumption of raw milk occur routinely every year. In 2007, the outbreak of Salmonella Typhimurium infection associated with raw milk and cheese consumption in Pennsylvania received national attention. The source of raw milk in this outbreak was from a dairy herd with a permit to sell raw milk. These outbreaks accounted for well over 1,500 illnesses, 100 hospitalizations, and at least two deaths. Unidentified or unreported cases of human illness associated with raw milk consumption likely add substantially to these numbers. Therefore, this project involves two important aspect of milk safety; i) Improvement of CIP cleaning for on-farm milking systems and processing equipment, and ii) Evaluating and improving the safety of raw milk production by licensed dairy producers in Pennsylvania.

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APPROACH: Further optimization of CIP cleaning by EO water for the pilot-scale milking system (# 1): The optimum conditions will be determined. <P>Pilot trial on a Penn State and/or a commercial dairy farm ((# 2): The optimum condition determined in Objective 1 for CIP cleaning of milking system will be validated on Penn State and/or commercial dairy farm by using real system for a period of one to three months depending on the results. <P>CIP cleaning of milk processing equipment ((# 3): EO water will be compared to conventional chemical detergents for cleaning a refrigerated tank, a processing tank and a pilot-scale high temperature short time pasteurization system. <P>Cost analysis and comparison of EO water with conventional method ((# 4): In order to demonstrate the economic benefit of EO water, a cost analysis will be performed by using operating cost such as water, electricity, salt, and maintenance and depreciation costs of the EO water generator and will be compared with costs of conventional cleaning method for both milking and milk processing systems. <P>
Outreach activities to transfer this technology to Dairy Farms ((# 5): Research results will be presented to the scientific and farming community. <P>Conduct surveys about the production, sale and consumption of raw milk in Pennsylvania and the implementation of best management practices on raw milk farms ((# 6). <P>Review questionnaires & survey instruments will be developed to establish their content and face validity and will pilot test the survey with a group of target audience volunteers. <P>Conduct a longitudinal study to determine the incidence, prevalence and variety of foodborne pathogens, and the quality of raw milk on licensed raw milk farms ((# 7): This study will determine the frequency and distribution of foodborne pathogens and milk quality in licensed raw milk herds over time. <P>Determine the change in, and major factors affecting the presence and type of foodborne pathogens under simulated, in-home storage conditions, and as well as the effect of simulated in-home heat treatment of experimentally-inoculated raw milk ((# 8): This part of the study will investigatethe change in the presence and type of naturally-occurring foodborne pathogens under simulated in-home storage and handling conditions and the major factors associated with the shelf-life of raw milk. <P>Perform a comprehensive risk assessment of the legal production, sale, and consumption of raw milk in order to estimate the risk associated with production and consumption of raw milk and the public health burden of foodborne illnesses due to consumption of raw milk ((# 9): Better understand the consumer's exposure risks resulting from the consumption of raw milk, and what the main risk drivers are for the consumer's exposure. <P>Use the findings of the risk assessment to drive a risk communication (extension/ education) effort aimed at producers and consumers of raw milk, as well as the veterinary and medical communities (# 10): Consumers will be provided with factual information on the probability of exposure to harmful pathogens in raw milk from licensed raw milk producers.