Recommendations for Maintaining Postharvest Quality
Maturity & Quality
Standard Tomatoes. Minimum harvest maturity (Mature Green 2) is defined by internal fruit structure indices. Seeds are fully developed and are not cut upon slicing the fruit. Gel formation is advanced in at least one locule and jellylike material is forming in other locules.
Standard tomato quality is primarily based on uniform shape and freedom from growth or handling defects. Size is not a factor of grade quality but may strongly influence commercial quality expectations.
Color. Uniform color (orange-red to deep red; light yellow). No green shoulders.
Appearance. Smooth and small blossom-end scar and stem-end scar. Absence of growth cracks, catfacing, zippering, sunscald, insect injury, and mechanical injury or bruises.
Firmness. Yields to firm hand pressure. Not soft and easily deformed due to an overripe condition.
U.S. grades are No. 1, Combination, No. 2, and No. 3. Distinction among grades is based predominantly on external appearances, bruising and firmness.
Maturity & Quality Photos
Temperature & Controlled Atmosphere
Mature Green: 12.5-15°C (55-60°F)
18-21°C (65-70°F); 90-95% R.H. for standard ripening 14-16°C (57-61°F) for slow ripening (i.e. in transit).For more details on ripening conditions see Ripening.
High relative humidity is essential to maximize postharvest quality and prevent water loss (desiccation). Extended periods of higher humidity or condensation may encourage the growth of stem-scar and surface molds.
To calculate heat production, multiply ml CO2/kg·hr by 440 to get BTU/ton/day or by 122 to get kcal/metric ton /day.
1.2-1.5µl/kg·hr at 10°C (50°F)
Tomatoes are sensitive to exogenous ethylene and exposure of mature-green fruit to ethylene will initiate ripening. Ripening tomatoes produce ethylene at a moderate rate and co-storage or shipment with sensitive commodities, such as lettuce and cucumbers, should be avoided.
Faster ripening results from higher temperatures between 12.5-25°C (55-77°F); 90-95% R.H.; 100 ppm ethylene. Good air circulation must be maintained to ensure temperature uniformity within the ripening room and to prevent the accumulation of CO2. CO2 (above 1%) retards the action of ethylene in stimulating ripening.
Controlled atmosphere storage or shipping offer a moderate level of benefit. Low O2 levels (3-5%) delay ripening and the development of surface and stem-scar molds without severely impacting sensory quality for most consumers. Storage times of up to 7 weeks have been reported for tomatoes using a combination of 4% O2, 2% CO2, and 5% CO2. More typically, 3% O2 and 0-3% CO2 are used to maintain acceptable quality for up to 6 weeks prior to ripening. Elevated CO2 above 3-5 % is not tolerated by most cultivars and will cause injury. Low O2 (1%) will cause off-flavors, objectionable odors, and other condition defects, such as internal browning.
Temperature & Controlled Atmosphere Photos
Physiological and Physical Disorders
Bacterial Soft Rot. Caused by Erwinia spp. can be a serious problem particularly if proper harvest and packinghouse sanitation is not used.
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How to Cite
Author(s) names. Initial publication or update date (located at the top). Title. Link to the specific Produce Fact Sheet webpage (Accessed date)
Example: Cantwell, M. and T. Suslow. 2002. Lettuce, Crisphead: Recommendations for Maintaining Postharvest Quality.