Tomato Glut at a Patiala Cooperative: Sell Fresh, Sun-Dry or Puree?
At a vegetable growers' cooperative in Patiala, 600 kg of ripe tomatoes are waiting under a shed on a 38 °C afternoon. The local mandi will take only 150 kg at ₹8/kg today; the rest has no buyer. The cooperative has no cold room. Tomatoes are losing about 15% of their remaining saleable weight each day to soft rot and cracking. Two options are on the table: open-sun drying, which needs about 8 kg fresh tomatoes per kg of dried product, or making puree on a small pulper rated at 40 kg raw material per hour. The pulper can run for six hours today, and puree yield is about 70%. Bottles, crowns and a permitted preservative are available for 250 kg of puree; beyond that, packaging would arrive tomorrow. Six workers are available, and the shed has no mechanical dryer. The cooperative must decide what to process now, what to sell fresh, and what to reject.
1. Using food-science principles, explain why these tomatoes are deteriorating so quickly and identify which process-fresh sale, sun drying or puree-best fits the cooperative's constraints. Justify your choice with the numbers given.
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Tomatoes are about 94% water, have a pH near 4.3–4.6 and respire after harvest. At 38 °C, respiration, pectinase activity and soft-rot organisms accelerate, so the 15% daily loss is plausible. Fresh sale can absorb only 150 kg, leaving 450 kg exposed. The pulper can process 40 kg/h × 6 h = 240 kg today, yielding about 168 kg puree. Packaging for 250 kg puree is available, so 240 kg raw material fits. Sun drying 450 kg at 8:1 would give about 56 kg dried product, but open-sun drying is slow, weather-dependent and exposes fruit to flies and dust. Best judgement: sell 150 kg fresh, puree 240 kg immediately, and sun-dry the remaining 210 kg only after sorting out spoiled fruit; that gives about 26 kg dried product. This uses the pulper at capacity while reducing the volume at risk. Pureeing everything is not possible today, and sun-drying alone leaves too much material exposed overnight.
2. Calculate the outputs if the cooperative sells 150 kg fresh and uses the pulper for the full six hours, then sun-dries the remainder. What practical risks would you flag before the plan is approved?
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Fresh sale: 150 kg. Remaining: 600 − 150 = 450 kg. Pulper input: 40 × 6 = 240 kg, leaving 210 kg for drying. Puree output: 240 × 0.70 = 168 kg. Dried output: 210 ÷ 8 = 26.25 kg. Total processed output is therefore 168 kg puree plus about 26 kg dried tomatoes. Risks: the 210 kg for drying will be held overnight and may lose more than 15% before drying starts; open drying needs turning, covers and protection from rain, birds and flies; puree needs adequate acid, preservative and hygienic hot filling, otherwise it will ferment; 168 kg puree must fit available bottles and be labelled; and workers must sort out cracked or rotting fruit first. The plan should set a cut-off: if the dryer cannot start by early morning, divert more fruit to puree or reject it rather than carry spoilage into the product.
3. What simple quality checks should be done on the raw tomatoes and on the puree before it is packed?
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Raw checks: sort by firmness, colour and smell; reject fruit with leakage, mould, deep cracks or off-odour; check for soil and foreign matter; measure approximate pH and total soluble solids on a representative sample. A firmness or hand-pressure check helps separate fruit suitable for sale from fruit for processing. Puree checks: measure pH and °Brix, look for separation, grit or black specks, smell for fermentation, and confirm the permitted preservative is within the allowed level. Hygiene checks should include worker handwashing, cleaned pulper and bottles, and a record of the batch. These checks are not a full laboratory analysis, but they give the cooperative a defensible release decision. If pH is above the intended range or the smell is off, the batch should be held rather than packed, because a swollen or fermented bottle later will cost more than the rejected puree.