In some cases, the CIP system isn’t the only culprit when PI and standard plate counts are high. So it was with a Utah producer who called, desperate for help, because high PICs and SPCs were robbing him of his bonuses. This dairy milks 1,500 cows in a 72-stall rotary parlor and had been experiencing problems since the system was built three years ago. The CIP detectives went to the scene to investigate and identified likely suspects in both the milking system and CIP system.
These profit bandits were picking the dairyman’s pockets by causing elevated bacteria counts and poor milkability.
Suspect #1: Pinched milk hose
With trained eyes on the milking process, we immediately observed a deficiency in the system: The milking unit on-time was far above ideal for cows in this herd. We always want to sustain quick, complete milking to reduce the risk of damage to the cows’ teat ends.
We dug a little deeper into the milking system and soon discovered a pinch point in the flexible 5/8-inch diameter milk hose connecting the claw to the back flush unit. This created inconsistent milk from the cows through the milking units to the milk line, causing the long unit on-time.
To obtain ideal vacuum, we replaced the flexible hose with 5/8-inch stainless steel tubing. Eliminating the pinch point ensures more consistent flow of milk from the cow and greatly reduces the likelihood of teat damage for the cows.
Suspect #2: Buildup in the slugger line
This farm’s CIP system uses an air injector to introduce controlled volumes of air into the system on an intermittent basis.
When working properly, the air injector cycles to allow a column of water to remove proteins, fats and mineral residue from the milk contact surfaces inside the milking system.
We inspected the injector system and discovered buildup in the slugger line due to inadequate water contact. This buildup is a perfect food to promote bacteria growth.
Closer inspection of the injector revealed that this part of the system was cycling too fast to draw enough water. We adjusted the injector’s on/off timing so an adequate volume of water is brought in to remove those deposits from the milk contact surfaces during each cleaning cycle.
Suspect #3: Collection reservoir carrying milky water to the wash vat
Finally, we inspected the milk collection tank. We noticed that milky water was returning directly into the wash vat, where it was mixing with the clean water and then flushed through the CIP system during the pre-rinse phase.
This leftover milk moving through the system during pre-rinse was leaving additional fats and proteins on the supposedly pre-rinsed contact surfaces, putting the milking system at risk for higher bacteria counts.
We installed a diverter valve in the milk transfer line, which is closed when the milking system is in use and open during the CIP system’s pre-rinse cycle. This diverter ensures that pre-rinse water isn’t contaminated by the leftover water from the collection tank.
The milky water goes directly down the drain during cleaning, and the pre-rinse cycle can run with truly clean water.
Complete scene inspection
As part of our detailed investigation of the scene, we inspected the farm’s water heating and verified that an adequate supply of hot water was available throughout the cleaning process. We then made sure that the correct amounts of detergents were being used for the water’s temperature and hardness.
With the milking and CIP system suspects rounded up, it was worth the time to make sure the entire cleaning process is running as it was meant to when it was installed.
The high bacteria counts in this farm’s milk were the result of improper operation and incomplete cleaning of the milking system. With the equipment problems fixed, this dairy is now milking and cleaning at peak performance and the producer’s profit is secure. Case closed.
It’s important to remember that adjustments like those we made on this farm may affect the operation of both your milking system and CIP system, so keep your eyes open and have your systems inspected regularly.
Always include a thorough evaluation of your system’s chemical use as part of your regular service schedule – it’s important to remember that milk quality really is the sum of several working parts. PD
TOP RIGHT: The blue milk hose in this photo constricts flow, causing inconsistent milk flow and longer-than-necessary unit-on time.
MIDDLE RIGHT: Upon close inspection, this milking system’s air injector, which should be pushing a column of water through the system during the wash cycle in order to remove proteins, fats and mineral residues, was cycling too fast to effectively remove deposits.
BOTTOM RIGHT: Milk from the collection tank was mixing with pre-rinse water, leaving milk contact surfaces vulnerable to higher bacteria counts. Photos courtesy of Ron Robinson.