High-Moisture Butter from Poorly Stored Cream
A cooperative butter plant has 1,000 kg of cream (40% fat) collected from three villages over 72 hours. The cream was held in a surface cooler at 8–10 °C because the ice bank was not working. Its free fatty acid content is 1.1% oleic acid and the cream has a slight rancid smell. It is churned at 14 °C. The butter leaving the churn has 18.2% moisture, 1.2% salt and visible buttermilk droplets; the salt is uneven. The plant wants to pack it as table butter for the local market because the fat and moisture tests are 'close enough' and the price is good. The food safety officer is due next week. The plant also has a ghee boiler and a rework vat.
1. Decide whether the batch should be packed as table butter, and justify the decision against quality and standards.
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It should not be packed as table butter. The batch has 18.2% moisture, above the normal table-butter limit of 16% moisture, and it contains visible buttermilk and uneven salt. High moisture and buttermilk create free water and salt pockets that favour mould, yeast and rancidity. The cream FFA of 1.1% oleic acid shows lipolysis and a rancid taint. 'Close enough' is not a legal or quality defence. Packing it would risk rejection by the food safety officer and loss of customer confidence. Hold the batch, do not print the table-butter label, and test moisture, salt, FFA and sensory quality before deciding its fate.
2. Explain the likely causes and propose corrective process changes.
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The cream was held for 72 h at 8–10 °C because the ice bank failed; lipase continues to act slowly at low temperature. Churning at 14 °C is too warm, giving soft butter, poor moisture expulsion and buttermilk retention. Uneven salt indicates insufficient working. Corrective changes: cool cream to 4 °C or below immediately after separation; pasteurise cream (for example 90–95 °C) to inactivate lipase and destroy microbes; limit cream storage to 24–48 h; churn at 10–12 °C, adjusted by season; wash with chilled water; work or knead to adjust moisture and salt; and check moisture and salt on every churn.
3. What can be done with this batch? Evaluate rework versus conversion to ghee.
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Do not sell it as table butter. Rework is possible: re-melt and re-churn can reduce moisture and improve salt distribution, but it cannot remove the rancid FFA. If the reworked butter meets the moisture, FFA and sensory standard, it may be packed as table butter; otherwise it must be downgraded. For ghee, test the ghee FFA and sensory quality after processing. If the FFA exceeds the legal limit for ghee, it cannot be sold as ghee; use it only for an approved technical or industrial purpose. Never blend high-FFA stock into good butter or ghee to 'average' the result; that hides a defect and is not allowed.