Understanding Coliform Downgrades

Summary:

Here you’ll find the key causes of coliform bacteria in milk and simple actions to improve hygiene, cooling, and prevent quality issues.

Coliform bacteria are fast growing bacteria which attach to the lactose (sugar) in milk and form strong-smelling compounds that impact the flavour of milk. The coliform test measures coliform bacteria in raw milk.

Downgrade support

Your milk quality results are available daily on your tanker docket or on the Farm Source website.

If your results are elevated (300 to 499 ml), you should carry out an immediate plant and vat hygiene check.

Organise a traceback

If you cannot determine the cause of the test result or you receive downgrades, call the Farm Source Service Centre.

Depending on the duration and severity of the issue, they will organise an on-farm trace back and take you through the Milk Quality Support Programme.

Refund support

Fonterra will refund up to the total amount of the deductions made under Clause 9.5 of the Fonterra Farmers’ Terms of Supply (“Terms of Supply”), in the current season, to cover the cost of help from a Fonterra approved service provider to solve milk quality problem.

Please refer the Terms of Supply Clause 9.7 for more information.

A snapshot of what to look for:

Hot water

  • Use an effective hot wash to remove build-up and kill bacteria
  • Check all surfaces are reached by wash water
  • Clean any areas the wash may miss

Rapid growth in warm milk

  • Cool milk quickly to below 6°C
  • Avoid holding milk warm for long periods
  • Check Dairy Diary for cooling standards

Effluent and soil

  • Keep the shed and plant clean
  • Avoid contamination from effluent and soil
  • Reduce dirt entering the milking system

How to prevent coliform downgrades

Early intervention is the best tool you have to prevent coliform downgrades.

Hot water and plant & vat cleaning:

  • Check wash water is 80–85°C and empty before it drops below 55°C
  • Do a daily hot wash with the correct detergent amount
  • Check wash performance, including injectors, jetters, flow, leaks, and blockage
  • Clean all non-contact areas like air lines, traps, seals, joints, and valves
  • Do not reuse filter socks
  • Clean air lines and miling cup clusters after liner splits or flooding
  • Check plate cooler for blockages the could cause milk deposit build-up
  • Complete monthly plant and vat hygiene checks using Dairy Diary app or the physical book

Rapid growth in warm milk:

  • Check primary cooling is working (milk exiting the PHE should be within 2–3°C of inlet water)
  • Fix cooling if the temperature gap is over 3°C
  • Service the refrigeration unit yearly and test before the season starts
  • Test cooling by running water in the vat and checking performance
  • Check the vat temperature gauge at each milking to confirm it’s working

Effluent and soil:

  • Keep the bail floor area clean during milking and put cups on clean teats
  • Prevent effluent ponding on races and minimise effluent build-up on feed pads

Water quality:

  • Check that the water used for plant cleaning and flushing purposes is of good quality 
  • Check that the water meets MPI requirements for clarity and being free from E coli.

Coliform mastitis:

  • Keep plant hygiene high – 95% of issues come from poor cleaning
  • Holding cows off pasture in a barn or stand-off pad may increase their risk of coliform mastitis
  • If you have concerns about coliform mastitis, speak to your vet or the Farm Source Service Centre

Training

  • PrimaryITO offers a Milk Quality Programme that aims to improve on-farm skills, knowledge and procedures to reduce the risk of downgrades while increasing the profitability of your dairy operation. 
  • This course has been developed in conjunction with Fonterra. 
  • To arrange training for you and your team, contact PrimaryITO on 0800 20 80 20 or visit their website. 
  • Alternatively, book a Milk Quality Service Visit.
Book a Milk Quality Service Visit