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Production Process Insights

Manual vs. Automatic: Sampling in the Dairy Industry

Posted by Israel Gamboa on 8/3/20 8:00 AM
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Automatic Sampling Dairy

In the dairy industry, it’s critical to safeguard product quality and safety, while maintaining proper custody transfers of milk and milk products. Automatic sampling is an important part of ensuring that each dairy manufacturer is providing true representation and adhering to product quality and safety standards.

Sampling for dairy safety and quality

The Food Safety Modernization Act (FSMA) of 2011 put a spotlight on improving safety in all food production. In addition, the Pasteurized Milk Ordinance (PMO, 2005) provides guidelines for safe milking practices, milk handling and sanitation of Grade A milk products. These guidelines are driving dairy producers to find new ways to improve their process monitoring systems.

Sampling of dairy products is necessary to ensure quality and safety. All types of dairy – cream, milk, whey, cheese – can be sampled in their various forms, from liquid and slurry to solid or powder.

Because of the issues with transporting dairy within a timely period for analysis, sampling often takes place at transport trucks, receiving docks and/or transfer points using dairy samplers specifically designed for those applications. 

manual sampling isn't enough

Manual sampling techniques, such as hand scoop, spigot sampling and dipper/ladle sampling are common sampling methods with milk and dairy producers and processors. These convenient and low-cost direct methods are widely accepted as an FDA approved operating procedure.

Manual sampling is usually conducted at two locations – at custody transfer and on processing lines. For example, manual sampling can be done during the transfer of milk from farm to milk truck. After the milk is agitated, the operator takes a milk sample with a dipper and sends it off for analysis.

However, manual sampling doesn’t keep up with FSMA regulations and doesn’t offer a complete look at the efficiency of your overall process. Manual sampling often introduces imprecision errors, sample size variation and sample bias, and contamination from human and equipment interactions.

ensure safety with automatic sampling

Automatic sampling helps dairy producers comply with state and local regulations and guidelines, while ensuring food safety and potentially reducing the risk of food recalls. It ensures representative dairy samples and makes it easier to document the sampling process. It also 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 starts the transfer pump and the sampler starts automatically capturing a representative sample for analysis.

Automatic sampling 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.

Because automated samplers provide a statistically representative sample, analysis data obtained from these samples offer a higher level of confidence from which important decisions about the process can be made.

  • Reliable– From validation of raw ingredients to quality testing, a representative sample is available throughout the entire processing stages
  • Accurate– A repeatable method that eliminates operator error
  • Shorten downtime – Sample at every level of processes without operator involvement and multiple sanitation
  • Verify ingredients– Verify that ingredients are being blended at appropriate ratios with a stratified sample
  • Product traceability - Track and verify ingredients from farm to final products throughout the supply chain

Building a representative sampling plan

A well-developed sampling program includes testing using analytical techniques to measure quality and contamination threats down to the parts-per-trillion. Considerations include:

Number of units – The number of units that comprise a representative sample from a designated lot of a food product must be statistically significant to be meaningful. According to the Bacteriological Analytical Manual, the adequacy and condition of the sample or specimen received for examination are of primary importance. If samples are improperly collected and mishandled or are not representative of the sampled lot, the laboratory results will be meaningless

Location of sampling point – The right sampling point facilitates access to the sample, where product is moving and where the material is homogeneous. A vertical leg is preferred.

Why the sample is being taken:


  • Bacteriological testing for salmonella, listeria, E. coli and more
  • Physical property testing to ensure specific attributes, such as butterfat content and moisture
  • Somatic cell count (SCC), as elevated SCC is associated with lower milk production

Automatic sampling solutions empowers the dairy industry to accurately monitor and measure processes for improved production efficiency, output and safety at both custody transfers and during in-line processes.

Learn more about Sentry dairy sampling solutions here.

Automatic Sampling: Why It's Essential for Food & Beverages

Topics: Food & Beverage, Solids & Powder, Liquid & Slurry

Written by Israel Gamboa

As a Regional Sales Manager, Israel Gamboa applies his expertise in oil refinery, food & beverage, petro chemical & chemical and power generation markets for customers in California and Canada. In his 10 years of Sentry experience, he’s served in Electromechanical Assembly, Field Service, Applications Engineering, Manufacturing Engineering and Outside Sales. Two highlights have been working with the oil sands industry for automatic sampling and with various oil refineries in North America for manual sampling. Gamboa believes in making his customer’s job easy by listening to their wants and needs and providing a sampling solution that exceeds their expectations.

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