In the dairy industry, it’s critical to maintain proper custody transfers of milk and milk products. To ensure quality and safety, milk and cream are often sampled at custody transfer points. Automatic sampling at custody points helps producers and processors comply with regulations, while maximizing product safety, quality and yield.
Sampling at custody transfer
Dairy producers and farmers milk their cows two to three times a day, and each cow produces about 37 liters of milk every day. This raw milk is immediately transferred into a bulk storage tank for cooling to 4°C (39°F). Cream contains typically 35% to 45% butterfat (although percentages can vary) and floats to the top of the milk. The raw milk or cream is then offloaded to tank trucks with a capacity of 5,000 to 12,000 gallons and taken to a local dairy processor, where it’s homogenized, pasteurized, packaged, or turned into other dairy products.
Prior to unloading the milk or cream, the processor often takes a manual sample with a sanitized dipper and sends it off for analysis by a lab. However, manual samples aren’t representative of the entire truck, as the butterfat often isn’t evenly distributed. Manual sampling can also introduce imprecision errors, sample bias and contamination from human and equipment interactions.
Contamination affects milk production and profits
The quality of raw milk and cream has significant influence over milk product yields and profits for both producers and processers.
The rapid cooling of milk can stimulate the growth of psychrotrophic bacteria, which grow at refrigeration temperature (7°C or lower). Numerous psychrotrophic microorganisms have been isolated from raw milk, and they’re one of the main contributors to a deterioration in milk quality that results in significant economic losses for the dairy industry.
This deterioration in milk quality translates as changes in flavor, undesirable coagulation of proteins, and an increase in the concentration of free fatty acids and amino acids. Psychrotrophs have a significant negative effect on yields, and they reduce the final dairy products’ shelf life.
Automatic Sampling Improves Custody Transfers
Automatic sampling ensures representative dairy samples adhere to product quality and safety standards. It also makes it easier to document the sampling process and simplifies the auditing of systems and processes to complete the custody transfer chain.
Within a process line, a sampler can automate preventive verification of critical process controls. For example, during the transfer of milk from farm to milk truck, an operator simply starts the transfer pump and sampler to automatically capture a representative sample for analysis.
Unlike a dipper, an automatic sampler reduces bias and provides a highly representative sample for analysis. Because automated samplers provide a statistically representative sample, analysis data obtained from these samples offer a higher level of confidence from which important decisions can be made.
Automatic sampling also allows a composite sample to be easily and safely obtained with no direct involvement from an operator. This ensures the integrity of the sample and increases efficiency over manual sampling, since the production line can continue without downtime. There’s no wait time to unload, as an operator doesn’t have to climb onto the truck and take samples.
These automated processes allow dairy processers to know they’re getting the correct butterfat content. And address any quality concerns immediately with the processor and farm before the raw milk or cream heads to the processing facility.
how automatic sampling at custody transfer works
Automatic samplers are installed downstream of the receiving pump to take evenly timed, composite samples as milk or cream flows past the sampler.
Milk Samplers can handle small volumes to deliver composite samples as the tanker unloads milk over approximately 20-40 minutes. Samplers for cream can handle larger samples with higher viscosity and butterfat content.
After unloading, a composite sample representative of the entire tank truck is then collected. There’s no variability because it’s taken the same way throughout the unloading process. Unlike manual samples, it’s consistent, accurate and repeatable.
Sentry’s automatic samplers provide true representative sampling over manual sampling. Our sampling solutions empower customers around the globe to accurately monitor and measure processes for improved production efficiency, output and safety.
Learn more about Sentry dairy sampling solutions here.