Dairy Processing Cooling Requirements: From Pasteurization To Cold Storage August 4, 2026 Dairy processing facilities have among the most demanding and diverse cooling requirements in the food industry. The same facility that heats milk to 161 degrees F for pasteurization must rapidly cool it to below 40 degrees F immediately afterward, maintain fermentation temperatures for cultured products, hold aging cheeses at precise humidity and temperature conditions, and stage finished products at refrigerated or frozen temperatures for distribution. Getting cooling right across all these applications is a core engineering and food safety requirement. Key Cooling Stages in Dairy Processing Receiving and raw milk cooling: raw milk must be cooled to 45 degrees F or below within 2 hours of receipt and held at 45 degrees F or below until pasteurization (FDA Grade A PMO requirements). Plate heat exchangers connected to chilled water or glycol are standard. Post-pasteurization cooling: pasteurized milk must be rapidly cooled from pasteurization temperature (161-165 degrees F for HTST; 280+ degrees F for UHT) to storage temperature (below 40 degrees F). The time-temperature relationship is critical; slow cooling allows heat-resistant organisms to survive and multiply. Cultured product fermentation temperature control: yogurt ferments at 108-113 degrees F (Lactobacillus bulgaricus and Streptococcus thermophilus); sour cream and kefir at different temperatures specific to their cultures. Active heating during fermentation, then active cooling to set the culture and halt acid development. Cheese aging: most traditional cheeses age at 50-60 degrees F with 80-95% relative humidity. Modern cheese caves with precision climate control produce more consistent aging outcomes. Frozen dairy products: ice cream processing requires product to reach -10 to -20 degrees F through continuous freezers, hardening tunnels, or hardening rooms. Dairy Product Critical Cooling Requirement Fluid milk (pasteurized) Below 40 degrees F within specified time post-pasteurization; continuous cold chain to consumer Yogurt 108-113 degrees F fermentation (active heating); rapid cool to 40-45 degrees F to halt fermentation at target pH Hard cheese (cheddar, gouda) 50-57 degrees F aging with humidity control; temperature and humidity stability affect texture and rind development Soft ripened cheese (brie, camembert) 50-55 degrees F with very high humidity (>90%); climate consistency critical to mold culture performance Cream cheese Rapid cooling post-processing; held at 35-40 degrees F; short shelf life demands cold chain integrity Ice cream Product temp reaches -10 degrees F in continuous freezer; hardening to -20 degrees F; storage at -20 to -30 degrees F "Dairy temperature control is a safety requirement first, and a quality requirement second. The sequence is important — failure to maintain food safety CCPs is not a quality problem; it's a regulatory and public health problem."— Paul Johnson, G&D Chillers Chiller Sizing Considerations for Dairy Plants Dairy processing creates highly variable cooling loads: Post-pasteurization cooling is a large, intermittent load — a batch of hot milk moving through a PHE creates a spike that may dwarf the facility's average cooling load Fermentation areas may require heating in the morning (culture activation) and cooling in the afternoon (culture arrest) — the heating and cooling loads may occur on the same equipment at different times Seasonal production variation in processing volume affects plant load profile Frequently Asked Questions What refrigerant is required for ammonia-free dairy plant cooling? Many large dairy plants traditionally used ammonia (NH3) refrigeration for its efficiency and low cost per ton. Modern facilities and expansions increasingly use HFC or HFO refrigerants with commercial chillers (like G&D's units using A2L refrigerants or R-134a), which eliminate ammonia's toxicity concerns and regulatory complexity while providing competitive efficiency. What is the FDA PMO requirement for raw milk cooling? FDA Grade A Pasteurized Milk Ordinance requires raw milk to be cooled to 45 degrees F (7 degrees C) or below within 2 hours of milking, and maintained at or below 45 degrees F until pasteurized. Receiving facilities must have cooling equipment capable of meeting this requirement for the maximum anticipated daily volume. > Design a comprehensive dairy processing cooling system with G&D -> Contact us