Friday, 18 October 2019 13:00

Milk cooled faster has higher quality

Written by  Staff Reporters

Milk cooling affects milk quality. The faster the milk is cooled after milking, the better its quality when it is collected from the farm.

Choosing the right cooling system for your farm means:

• Lower energy costs

• Milk cooling accounts for about 30% of the total energy costs of operating a dairy: energy demand and farm dairy operating costs can be reduced using different options that involve heat recovery from your cooling system.

• Less risk of penalties due to milk temperature

• Raw milk grows bacteria rapidly above 7°C. Meeting the new milk cooling standards, which took effect for all farms on June 1, 2018, may mean changes are required for your system.

Plate heat exchangers (PHE) are a highly cost-effective way to cool milk.

A PHE consists of a series of very thin stainless steel plates. Water flows along one side of each plate while milk flows along the other. Heat is transferred from the milk to the water via the plate. The cooling capacity of a plate cooler is adjusted by adding or subtracting plates.

The easiest way to check the effectiveness of your plate cooler is to compare the difference in temperature between the incoming cooling water and the milk leaving the plate cooler.

An efficient PHE should cool milk to within 2°C of the water temperature before it enters the PHE. For example, if the temperature of the incoming cooling water is 14°C, the temperature of the milk exiting the plate cooler should be about 16°C.

One simple way to check this is to use a PVC strip thermometer. These thermometers have a paper backing which is peeled off and stuck directly onto a clean, dry metal pipe.

PVC therometer usage

1. Locate the water inlet pipe and the milk outlet pipes where they enter and leave the plate cooler, respectively.

2. Find a location for the thermometer that allows it to wrap around the outside of the water inlet pipe. It must be placed on a metal pipe so you may need to move the rubber hose a little to make enough room. 

A piece of electrician’s or gaffer tape on each end of the strip can help you with initial positioning. Rotate the thermometer to ensure the temperature range you expect at the pipe is visible. Repeat the process by applying another thermometer strip to the milk outlet pipe.

3. The temperature blocks light up, with the brightest one being the temperature of the pipe. At the next milking, check to see if the required temperature range is visible.

4. Remove the tape on the thermometer strips and once the pipes are clean and dry, remove the paper backing and stick the strip thermometers permanently to their respective pipes.

5. Check the two temperatures during peak milk flow from the milk pump. If there is more than 3°C of difference there is room for the plate cooler’s performance to be improved. In this situation consider checking the water and milk flow rates through the plate cooler.

More like this

Maintaining milk flows to pay the bills

As spring calving farmers around the country enter in the final stage of lactation, the incentive to keep the milk flowing is certainly there. A strong milk price and kind first half of the season has left cows in good nick and milking well.

Milk chilling partnership

Fonterra farmers can now lease next generation milk chilling technology and enjoy the many benefits that come with it.

Necessity is the mother of invention

John and Donna McCarty no longer use intermammary antibiotics for mastitis or dry cow treatment, which has saved them money and improved herd health.

Featured

NZ household food waste falls again

Kiwis are wasting less of their food than they were two years ago, and this has been enough to push New Zealand’s total household food waste bill lower, the 2025 Rabobank KiwiHarvest Food Waste survey has found.

Editorial: No joking matter

OPINION: Sir Lockwood Smith has clearly and succinctly defined what academic freedom is all about, the boundaries around it and the responsibility that goes with this privilege.

DairyNZ plantain trials cut nitrate leaching by 26%

DairyNZ says its plantain programme continues to deliver promising results, with new data confirming that modest levels of plantain in pastures reduce nitrogen leaching, offering farmers a practical, science-backed tool to meet environmental goals.

National

Machinery & Products

JDLink Boost for NZ farms

Connectivity is widely recognised as one of the biggest challenges facing farmers, but it is now being overcome through the…

New generation Defender HD11

The all-new 2026 Can-Am Defender HD11 looks likely to raise the bar in the highly competitive side-by-side category.

» Latest Print Issues Online

Milking It

Full cabinet

OPINION: Legislation being drafted to bring back the controversial trade of live animal exports by sea is getting stuck in the…

No Joy

OPINION: Milking It understands a formal disciplinary process is being conducted by Victoria University of Wellington on what one of…

» Connect with Dairy News

» eNewsletter

Subscribe to our weekly newsletter