NZ Dairy Autumn 2022

70 | nzdairy DAIRY SERVICES » School of food Advanced Technology A modern milk vat set up on farm (above). Foam is evidence of air in milk (below). Richard Loader Professor Richard Archer, of the School of Food and Advanced Technology at Massey University says New Zealand has some of the best milk in the world at the udder, but not when it hits the factory. For most Kiwi farms, the milk vat belongs to the dairy company, but the vats we put on farm tomorrow will be there, affecting milk quality, for 30 years. “New Zealand knows it needs to make higher margin products than powder, but that will need top quality milk. UHT milk can’t afford heat-stable enzymes. Culinary cream can’t afford broken fat globule membranes. Now is the time to start putting equipment on farms that will ensure milk is good in 2050. Over the next 30 years we can gradually upgrade the quality of milk feeding our factories – probably catchment by catchment.” So what are the current deficiencies? Entrained air can be present in the milk right from the beginning. If the agitator is switched on too early, more air is whipped into milk. Too late delays cooling. Milk can slosh around a half-full tanker incorporating even more air. “Air in milk is not great but air bubbles combined with the shear generated by pumps and heat exchangers can be very damaging to fat globules, exposing milk fat to enzymes.” The current agitator is the biggest maintenance item. Being roof-mounted maintaining it requires two people for safety. The manway must be left open for ventilation during the CIP but this gives access to birds or vermin. “The dimple pad is expensive and requires a large charge of refrigerant, ‘says Richard. “The refrigerants we use now are nearly all high GWP (Global Warming Potential). When they leak farmers pay the carbon charges for the replacement charge and it adds to the emissions of the farm. If we can do without a dimple pad you have much less refrigerant, low enough for flammable refrigerants to be safe, and a simpler agitator.” The vat is not insulated, and the top can get hot and grow biofilms at the high tide mark or anywhere reached by foam or splash. “At 6° Celsius milk will last a couple of days tops — even skip-a-day means lots of tanker visits. If the tanker visits within a couple of hours of milking it may be well above 6° C. But, if all milk was 4° C the minute it hit the silo, tanker scheduling can take another step up. There are many pointers toward a new vat style, heavily insulated to allow several days storage in adversity but with no on-board cooling, coupled to snap chilling. Maybe 5% of Kiwi farms currently snap-chill, while in some parts of the world it is already the norm. “If a new vat style is to be used in New Zealand it should be designed for our conditions and made here. To make sense, a new vat must be better not only for the milk, but also the farmer, driver, processor and regulator.” A vat for New Zealand must fit on a truck under New Zealand road rules, perform to MPI requirements and fit the seismic codes in our shakiest farms. Ideally it will be cheap to build, robust and maintenance-free while its interior has the same The need for a new style of Milk Vat filtered air quality as the inside of a factory, and an inspection hatch that is opened maybe once a year. “The current vat will make no sense in 2050 and a new vat is coming for sure,” says Richard. “But a new vat invokes a new system — snap chilling, reduced air, gentler milk handling. The exact shape of all this is not clear, but the direction of travel is: toward icebanks to store up cold; toward reduced electrical draw on fading lines infrastructure; toward something we can be proud to show buyers of New Zealand dairy products.” “If a new vat style is to be used in New Zealand it should be designed for our conditions and made here. To make sense, a new vat must be better not only for the milk, but also the farmer, driver, processor and regulator.” Paul 027 244 3354 | Kyllee 027 688 8677 Paul & Kyllee Henton • DAIRY • DEER • EQUINE • PIGS • BEEF • SHEEP • ANTI-FATIGUE • WINTERING @AgriTechImportsNZ Brad Hosking 027 754 6075 - 24 hours of MILKING SYSTEMS ead Specialising in: • Complete Dairy Shed Maintenance • New Dairy Shed Builds • Platform Repairs and Maintenance • Water and Effluent Management • General Engineering • Registered Milking Machine Technician