University of Wisconsin Dairy Update On-Farm Pasteurization of Milk for Calves Matt Jorgensen and Pat Hoffman Introduction Listed in the table are the time and temperature guidelines set forth for human consumption. All dairy operations have a supply of milk that is not saleable, commonly called waste milk. Waste milk can be Temperature(°F) Time defined as excess colostrum, non-saleable transition milk, 145 30 min mastitic milk or non-saleable antibiotic treated milk. In the past, waste milk was commonly fed to calves but 161 15 sec concerns with bacteria contamination such as E.coli and 191 1 sec salmonella as well as larger concerns with possible transmission of diseases such as Mycobacterium 194 .5 sec paratuberculosis (Johnes) through feeding waste milk 201 .1 sec have led to a general recommendation not to feed raw waste milk to calves. 204 .05 sec 212 .01 sec Pasteurization of waste milk for calves is one option to reduce management risk while utilizing a valuable low cost liquid feed source for calves. Milk has been It should be noted that pasteurization temperatures for pasteurized for human consumption for many years, but milk containing a high fat content (10 %) should be milk pasteurization equipment and technology has been increased 5° F. This scenario can be very typical for relegated to dairy plants bottling milk or waste milk that can be very high in fat producing dairy products for human content. consumption. Currently, companies are starting to produce, smaller, self- Typical on-farm applications for contained, on-farm pasteurizers pasteurization of waste milk for calves specifically for the utilization of waste involve homemade batch pasteurization milk to feed to calves. These smaller on- systems or commercially produced farm pasteruizers are being marketed at continuous-flow (CF)/flash/high prices that now make the technology temperature, short time (HTST) affordable to an individual dairy operation pasteurizers. Commercially produced CF to consider. pasteurizers feature a heating system with 1 to 15 second retention time, cooling reservoir tank and How Pasteurization Works clean in place (CIP) systems. Specific pasteurizers are also being marketed for the pasteurization of colostrums. Pasteurization was named after Louis Pasteur whom discovered that simple heating could inactivate spoilage Typically, non-agitated batch pasteurizers and CF organisms in wine. The process was later transferred to pasteurizer do not work very well for colostrums because other commodities such as milk. The actual definition of colostrum has a tendency to thicken and flow poorly when pasteurization is; the heating of every particle of milk to a heated to pasteurization temperatures. Despite altered specific temperature for a specific time to reduce physical characteristics, the immunoglobulins and growth undesirable enzymes and bacteria to negligible levels. It factors in colostrums have been shown to be completely is important to understand the pasteurization is not total bioactive after careful pasteurization. sterilization of the milk. It is also important to note that pasteurization is function of time and temperature not just Generally, newly available on-farm waste CF temperature. pasteurization units heat milk to 162° F for 15 seconds. Clinical studies have shown that this combination is effective at killing the bacteria such as Staphylococcus, 1 Streptococcus, Salmonella, E. Coli, Listeria, and the about the long term feeding aspects and risk associated Johnes organism Mycobacterium paratuberculosis, as with feeding pasteurized waste milk. well as most Mycoplasma bacterium. What About Calf Health It is important to note that pasteurization does not kill all the There are two aspects of feeding bacteria, but it reduces numbers of pasteurized waste milk on calf health organisms present to extremely low that need to be considered. First, levels. Despite its effectiveness, feeding pasteurized waste milk has extremely contaminated or notable been demonstrated to improve calf abnormal milk should be discarded health as compared to feeding raw and not pasteurized because its waste milk. In a California study, nutritional characteristics for calves calves fed pasteurized waste milk cannot be assured. had lower incidence of scours and pneumonia; labor cost to treat calf Potential Benefits diseases was also lower. The potential to have an acute disease outbreak in calves should be greatly reduced if A benefit to on-farm commercial waste milk pasteurizers waste milk is pasteurized as compared to feeding raw is that they are becoming relatively easy for users to waste milk. operate, clean, and maintain. Control systems are simple and easier to understand and installation is not complex. Calf health aspects of feeding pasteurized waste milk as On-farm pasteurizers are relatively small, taking up the compared to feeding milk replacer have not been well space of a small milk bulk tank. Calf nutrition is relatively defined. Assuming a high quality milk replacer is fed to unaltered by feeding pasteurized milk. In research trials calves, there would be no apparent logic to suggest any at the University of California-Davis, feeding pasteurized major differences in the incidence of calf disease between milk resulted in calves having fewer days of scours and calves fed milk replacer or pasteurized waste milk. pneumonia, when compared to non-treated milk. Calves fed typical pasteurized waste milk feeding rates (2 Pasteurized waste milk will contain more protein (25-30%) quarts/feeding) will consume significantly more energy and fat (25-35%) on a dry matter basis than a standard and protein as compared to a typical feeding rate of 1.0 lb 20% protein, 20% fat milk replacer; thus pasteurized DM/calf/day of a 20:20 milk replacer (2 quarts/feeding). waste milk is more energy dense on a dry matter basis Calves on higher plane of nutrition are less likely to than typical milk replacers. succumb to mal-absorption during scours events. Milk replacers; however, can and are being reformulated and Potential Problems fed at different rates to optimize nutrient intakes. Dairy operations have to consider their supply of waste milk. To be practically effective a dairy operation must Pasteurizer Set-Up have a stable supply of waste milk. A stable supply of Currently available flash pasteurizers are easy to set-up waste milk is critically important because the liquid feed and are generally self-contained. Units generally require fed to calves should not be changed frequently. For a dedicated circuit at 240 volt, and a 50-80 amp smaller herds this is sometimes difficult because days or receptacle (depending on the size of the unit). Water is weeks can go be where there is no waste milk at all. also required for the pasteurization unit. A drain is also Quality control is also an issue that demands constant required to dispose of water and cleaning solutions. No attention. Milk pasteurizers need to be operated, hard plumbing is typically required to set up the unit. evaluated, and maintained so a quality product is produced. Milk pasteurizers are also an investment The methods of heating milk to pasteurization requiring a return on investment. temperature will determine the water temperature that is needed. If pasteurization temperature is achieved Additionally, little is known about the effects of electrically, water needs to enter the unit at 95-115° F to pasteurization on antibiotic residues in milk. Some cool the milk after pasteurization. antibiotics are heat sensitive and maybe rendered inactive other antibiotics are not. Calves fed pasteurized However, some units reach pasteurization temperature waste milk maybe contaminated with antibiotic residue using water. These units require a dedicated water and would be un-saleble as result until after the heater that will reach pasteurization temperature. appropriate withholding periods. Finally, little is known Typically, units that use a water-heat exchanger will have 2 a feedback loop to cool milk that has been pasteurized. A Tips for Success lower cost option is to let the milk air cool. · Routinely culture samples of pasteurized milk to Because bacteria can survive on debris like hay, manure, monitor quality. and insects, most units now include a filter screen for · Train all employees that will be using the unpasteurized milk. It is vitally important, from a quality pasteurizer to be sure they understand how to control standpoint, that this screen be in place whenever operate the unit and what the concepts of raw milk is put into the machine. In addition, waste milk pasteurization is. should be properly refrigerated and keep as hygienic as · Conduct follow-up training and review for possible prior to pasteurization. employees · Do not pasteurize extremely abnormal milk Clean up of the units is not unlike cleaning milking because nutritional characteristics may be altered equipment. A hot water, alkaline wash followed by an · If calf death loss occurs, diagnose calf morbidities acid rinse is typical. The hot water used for washing and mortalities. needs to be supplied at 135-145° F. This water is · Know how to manually check the temperature of typically supplied from a sink or exterior hose, not the pasteurized milk to ensure proper temperatures water supply that is needed during pasteurization. Some are being met. units may offer an automated cleaning cycle, others · Visit other operations successfully using on-farm require hand washing of some components. waste milk pasteurization systems. Economics