Understanding Somatic Cell Count in Milk: A Key Factor for Cheese and Yogurt Production

Somatic cell count (SCC) is a critical indicator of milk quality and udder health in dairy animals. For dairy industry professionals, managing SCC is essential to ensure high-quality cheese and yogurt production. This blog post explores the significance of SCC, target levels, and its impact on dairy processing, with practical insights for optimizing outcomes.

What is Somatic Cell Count?

Somatic cells are primarily white blood cells (leukocytes) and epithelial cells present in milk. Elevated SCC typically indicates mastitis, an udder infection, or other stressors affecting dairy animals. Measured in cells per milliliter (cells/mL), SCC is a standard metric used globally to assess milk quality.

• Why it matters: High SCC compromises milk composition, affecting protein, fat, and lactose content.
• Industry relevance: Regulatory bodies, such as the U.S. Pasteurized Milk Ordinance and EU regulations, set SCC limits to ensure consumer safety and product quality.

For cheese and yogurt producers, understanding SCC is vital, as it directly influences yield, texture, and flavor.

Importance of Somatic Cell Count in Dairy Production

SCC is more than a health indicator; it’s a determinant of processing efficiency and product quality. Here’s why dairy professionals prioritize low SCC:

1. Milk Composition: High SCC reduces casein and lactose, critical for cheese curd formation and yogurt fermentation.
2. Yield Efficiency: Elevated SCC lowers cheese yield by up to 1–2% per 100,000 cells/mL increases above 200,000 cells/mL.
3. Product Quality: High SCC can lead to off-flavors, poor texture, and reduced shelf life in cheese and yogurt.
4. Regulatory Compliance: In the U.S., the legal SCC limit is 750,000 cells/mL for Grade A milk, while the EU sets a stricter threshold of 400,000 cells/mL.

Maintaining low SCC ensures consistent production and meets stringent quality standards.

Target Somatic Cell Count Levels

For optimal dairy processing, experts aim for the following SCC targets:

• Ideal Range: Below 200,000 cells/mL. This ensures minimal impact on milk quality and maximizes yield.
• Acceptable Range: 200,000–400,000 cells/mL. Suitable for most cheese and yogurt production, though slight yield losses may occur.
• High Risk: Above 400,000 cells/mL. Significant quality and yield issues arise, often requiring intervention.

Pro Tip: Regular monitoring using automated SCC counters and mastitis management programs can keep levels below 200,000 cells/mL.

Impact on Cheese Production

High SCC affects cheese production at multiple stages:

• Curd Formation: Elevated SCC reduces casein, leading to weaker curds and lower yields. For example, SCC above 400,000 cells/mL can decrease cheddar yield by 1.5–3%.
• Ripening: High SCC increases proteolysis, causing off-flavors and inconsistent texture in aged cheeses like Gouda or Parmesan.
• Processing Conditions: Milk with high SCC may require adjustments in rennet dosage or coagulation time. Optimal coagulation occurs at 30–32°C (86–89.6°F), but high SCC can disrupt this process.

Solution: Use milk with SCC below 200,000 cells/mL and maintain precise temperature control during coagulation (e.g., 31°C/87.8°F for cheddar).

Impact on Yogurt Production

Yogurt production is equally sensitive to SCC:

• Fermentation: High SCC lowers lactose, slowing fermentation by Lactobacillus and Streptococcus cultures. Ideal fermentation occurs at 40–43°C (104–109.4°F).
• Texture: Elevated SCC weakens gel structure, resulting in grainy or runny yogurt.
• Flavor: Proteolytic enzymes from somatic cells can introduce bitter notes, affecting consumer acceptance.

Solution: Blend milk batches to achieve SCC below 200,000 cells/mL and standardize fermentation at 42°C (107.6°F) for consistent results.

Strategies to Manage Somatic Cell Count

Dairy professionals can adopt these practices to control SCC:

1. Herd Health Management: Implement mastitis prevention through proper milking hygiene and regular veterinary checks.
2. Milk Testing: Use monthly SCC testing to identify high-risk animals and segregate their milk.
3. Processing Adjustments: For milk with moderately high SCC (200,000–400,000 cells/mL), adjust starter culture concentrations or ripening times.
4. Education: Train staff on SCC’s impact and best practices for udder health.

Conclusion

Somatic cell count is a pivotal factor in cheese and yogurt production, influencing yield, quality, and compliance. By targeting SCC below 200,000 cells/mL and optimizing processing conditions—such as coagulation at 30–32°C (86–89.6°F) for cheese or fermentation at 40–43°C (104–109.4°F) for yogurt—dairy professionals can achieve superior results. Regular monitoring and proactive herd management are key to maintaining low SCC and ensuring consistent, high-quality dairy products.

Call to Action: Share your SCC management strategies in the comments or contact us at DairyCraftPro for expert advice on optimizing your dairy production!

References

1. Barbano, D. M., Ma, Y., & Santos, M. V. (2006). Influence of raw milk quality on fluid milk shelf life. Journal of Dairy Science, 89(E3), E15–E19. https://doi.org/10.3168/jds.S0022-0302(06)72360-1
2. Politis, I., & Ng-Kwai-Hang, K. F. (1988). Effects of somatic cell counts and milk composition on cheese yield and quality. Journal of Dairy Science, 71(7), 1711–1719. https://doi.org/10.3168/jds.S0022-0302(88)79739-0
3. Auldist, M. J., & Hubble, I. B. (1998). Effects of mastitis on raw milk and dairy products. Australian Journal of Dairy Technology, 53(1), 28–36.
4. Schukken, Y. H., Wilson, D. J., Welcome, F., Garrison-Tikofsky, L., & Gonzalez, R. N. (2003). Monitoring udder health and milk quality using somatic cell counts. Veterinary Research, 34(5), 579–596. https://doi.org/10.1051/vetres:2003022