Glossary
Dairy and food processing

What is Milk chilling and bulk milk coolers?

Definition

Milk chilling is the rapid cooling of raw milk after milking or collection to slow bacterial growth, done in farm bulk milk coolers, village chilling centers and plate chillers at plant intake.

Where raw milk is chilled

On large farms the bulk milk cooler is a refrigerated, insulated tank fed straight from the milking system. In India and other markets built on smallholder supply, milk goes to bulk milk coolers at village collection points or to chilling centers before a tanker takes it to the processing plant. Each stage adds a refrigeration load that may run on grid power, a diesel generator or both.

What sets chilling cost

The cooling duty depends on how much milk arrives, how warm it is and how quickly it must reach storage temperature. Capacity is rated in tons of refrigeration or kilowatts, and efficiency is the cooling delivered per unit of electricity. Pre-cooling milk through a plate cooler with well water or chilled water reduces the compressor's share of the work. Time and temperature limits for raw milk come from the food regulator in each market and should be read from the current rule.

How Aqueduct watches a cooler fleet

Each cooler gets an electricity meter and a milk temperature probe, which together give energy per liter chilled and minutes to reach set point for every collection. aQ PredictIQ watches compressor run time and condenser behavior for drift across the fleet. The device Health tab shows which remote site has a sensor with a weak connection or low battery, so a field visit is planned instead of discovered.

Questions

Milk chilling and bulk milk coolers: common questions

A bulk milk cooler is a refrigerated stainless steel tank that receives raw milk and brings it down to storage temperature quickly, then holds it until collection. Coolers sit on farms and at village collection points, and each one is a refrigeration load. See refrigeration and cold chain.

Dirty condensers, low refrigerant charge, warm milk delivered late in the day and worn tank insulation all lengthen compressor run time. Comparing energy per liter across similar coolers usually shows which unit to inspect first.

Yes. Washing water is dairy effluent under the Environment (Protection) Rules, 1986, and the CPCB dairy standard allows BOD up to 350 mg per liter for chilling plant effluent applied on land only where that land is designed and monitored as a secondary treatment system.

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