A milk grade is often a sign that you have milk soil somewhere in your plant and your plant isn’t doing its job properly. Cracked rubbers, worn jets, leaking seals, or dodgy joins can all create the perfect breeding ground for bacteria. A full plant inspection helps you find the weak links before your milk grades again.
What You’ll Need
A torch
Clean dry cloth
Mirror (optional, but handy for hard-to-see spots)
Gloves
Notepad or phone for recording issues
Replacement parts if you’ve already got them
What You’re Looking For
Milk/protein deposits – rainbow or brown in appearance.
Rubberware that’s cracked, stretched, or sticky
Any residue that doesn’t rinse off easily
Damaged or cloudy plastic
Loose, leaking, or missing seals
Areas that feel slimy to the touch or smell off
Don’t forget to check your temperatures, both precooling and refrigeration
Step-by-Step Instructions
1. Turn everything off and drain the plant
Make sure the system is safe to work on. Drain milk lines and turn off water and power.
2. Vat inlet line and door seal
Start here first as it only takes a few minutes. No point spending hours in other areas to find the problem under a stirrer or paddle. Inspect everywhere.
Remove the door seal and inspect closely for milk soil deposits.
Look for butterfat build-up, especially if you’re failing on coliforms or bactoscan.
Purple or brown protein deposits especially for thermodurics.
3. Now the clusters and cups
Check for cracks, perished rubber, or build-up in claws (remove sight glasses to check bases) and short milk tubes.
Look and feel inside cups and lines for residue or film. If it shines under a torch, it needs cleaning.
4. Inspect the jetters and airline seals
Pull jetters apart and look for gunk in crevices.
Check and smell the airlines, both pulsator and receiver for signs of milk.
Check for air leaks and rubber that’s lost its grip. Loose seals are a silent problem.
5. Move along the milk and wash lines
Shine a torch through the milk line. Look for residue, purple or brown film, cracks, or cloudy plastic.
Check joins for leaks or worn seals. If it’s not airtight, it’s not working.
6. Look at the receiver and sensor probes
Build-up can hide in the float switch, milk inlet and level probes. Common protein deposit areas are at the upper surfaces - double check these.
Wipe everything down and clean manually if needed.
7. Open the milk pump
Check for splits, perishing and foreign matter in the non-return valves.
8. Open up the milk filter housing
Check for cracks and damage, especially the top of the tube and around end seals of the cage. Any surface that holds milk needs to be spotless and sealed.
9. Check the plate cooler
Open and inspect the plate cooler. Looking for foreign matter and damaged seals.
10. Finally, find and inspect the test bucket hose
Clean the bucket, hose and valve.
BONUS. Don’t forget to check your temperatures - both cooling and refrigeration.
Pro Tips
Do this every 1 to 2 months, not just after a grade.
If you’ve cleaned problem areas and bomb washed, yet still have a problem, a full plant inspection is the next step.
Use your phone to take photos of anything suspicious. These pictures help if you need to call in further assistance.