Harvesting and Handling
Carrots can be harvested either bunched or top trimmed; top trimmed is the dominant method.
Harvest maturity varies with the market outlet and the end usage. For fresh market, most carrots are harvested partially mature, when the roots are about 2 cm or larger in diameter at the upper end. Late harvesting may improve storability by reducing decay during extended storage. For fresh-cut processing, carrots are harvested immature to insure they are tender and sweet.
There are many visual and organoleptic properties that differentiate the diverse varieties of carrots for fresh market and minimal processing. In general, carrots should be:
-Firm (not flacid or limp)
-Straight with a uniform taper from ‘shoulder’ to ‘tip’
-There should be little residual “hairiness” from lateral roots
-No “green shoulders” or “green core” from exposure to sunlight during the growth phase.
-Low bitterness from terpenoid compounds
-High moisture content and high reducing sugars are most desireable for fresh consumption
Bruising, shatter-cracks, longitudinal cracking, and tip-breakage are signs of excessively rough handling. Wilting, shriveling, and rubberiness are signs of moisture loss. Sprouting may occur on topped carrots if the storage temperature is too high. Bitterness can develop in storage due to the accumulation of isocoumarin, caused by disease or exposure to ethylene. Harsh flavour may be caused by the high terpenoid content, generally from pre-harvest water stress. Surface browning or oxidative discoloration often develops during storage, especially on carrots harvested when immature.
Cooling and Storage
Prompt washing and hydro-cooling to < 5 °C is essential to maintain carrot freshness and crispness. Typically, carrots pass through several wash and flume steps that remove field heat and are then hydrocooled in chlorinated water before packing.
The recommended conditions for commercial storage are 0°C to +1°C with >95% RH. Under these conditions, mature topped carrots can be stored for 5-6 months. Most carrots for the fresh market are not fully mature. These immature or partially mature carrots are topped and packed in (permeable) polyethylene consumer bags or mesh bags for marketing. If pre-cooled promptly before packaging and trimmed of all traces of leaf growth, they can be held 4 to 6 weeks at 0°C, with >95% RH. Bunched carrots are highly perishable due to the presence of leaves and can be maintained for only approx. 2 weeks.
Carrots are not chilling sensitive and should be stored as cold as possible without freezing. The highest freezing point for carrots is -1,2°C. Severe injury in carrots immediately after freezing is identified by lengthwise cracking and by blistering caused by the formation of ice crystals immediately beneath the surface. After thawing, a darkened (dark brown or black) and watersoaked skin is observed, and the carrots are soft and flabby.
Controlled atmosphere considerations
CA generally does not extend storage-life of carrots beyond that in air with high RH.
Aspergillus black mould, Bacterial soft rot, Blue mould, Cavity spot, Freezing injury, Fusarium, Scab, Sprouting.