Tanker Acceptance at a Kolhapur Dairy
A cooperative dairy in Kolhapur receives 1,800 L of cow milk from a village chill centre at 5°C. The tanker sample shows titratable acidity 0.17% lactic acid, MBRT 35 minutes, clot-on-boiling negative, fat 3.6% and SNF 8.4%; the sensory panel finds no off-odour. The morning market needs 1,200 L of pasteurized toned milk, and the paneer section can take up to 600 L. The quality officer must decide by 6 a.m. whether to accept the whole lot for pasteurization, divert 600 L to paneer, or reject it. The plate HTST pasteurizer is set for 72°C/15 s, and the paneer vat uses 0.8% citric acid solution; the unit's purchase specification says milk for paneer should have acidity below 0.18%, MBRT above 30 minutes and a negative clot-on-boiling test. The previous tanker had 0.14% acidity and MBRT 50 minutes. The dairy also has 300 L of fresh milk in the silo.
1. Interpret the four quality results and classify the tanker. Should the officer accept all, part, or reject? Give the decision and the reasoning.
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The lot is not a reject, but it is not premium milk. Acidity 0.17% is at the upper end of the acceptable range (fresh cow milk is usually 0.14–0.16%), MBRT 35 min is above the 30-min minimum but well below the previous 50 min, and clot-on-boiling is negative, so the milk is not sour enough to coagulate. Fat and SNF are normal. The officer should accept conditionally: use 1,200 L for pasteurized toned milk, because HTST will improve microbiological quality but will not remove the slight acidity; do not use it for UHT or long-held chilled milk. For paneer, 0.17% is below the 0.18% purchase limit but close to it, so a direct 600 L vat may give low yield and brittle body. A better disposition is to blend the 600 L with the 300 L fresh milk: (600×0.17 + 300×0.14)/900 = 0.16%, which gives a safer paneer feed. Reject only if clot-on-boiling becomes positive, off-odour appears, or MBRT falls below 30 min.
2. If the lot is accepted, state the critical process controls for the toned milk and for the paneer, and one verification test for each.
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Toned milk: HTST 72–75°C for 15 s with a functioning flow-diversion valve; cool to 4°C; verify with alkaline phosphatase negative and MBRT of the pasteurized product. Paneer: heat the blend to 85–90°C, cool to 70°C, add 0.8% citric acid solution slowly with stirring until pH 5.3–5.4, hold 5–10 min, drain whey, press, and chill. Verify coagulation pH and whey acidity; check yield. The higher initial acidity means less acid is needed, so add citric acid in increments rather than a fixed volume.
3. Write the acceptance/rejection note the officer should record, including disposition and a condition for release.
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Record: Tanker T-xx, 1,800 L, 5°C; acidity 0.17%, MBRT 35 min, COB negative, fat 3.6%, SNF 8.4%. Decision: accepted conditionally. Disposition: 1,200 L to toned milk; 600 L blended with 300 L fresh silo milk (final acidity about 0.16%) to paneer. Release condition: toned milk only after negative phosphatase and MBRT ≥30 min; paneer only after a coagulation trial gives satisfactory curd and normal whey. If COB becomes positive or off-odour develops before processing, reject the lot and record the reason.