Tomatoes

Infobox on Tomatoes
Example of Tomatoes
Freshness facts
Optimum carrying temperature	12°C to 15°C (mature green) 10°C to 12°C (turning) 8°C to 10°C (ripe)
Highest freezing point	-0,5°C
Acceptable product temp. at loading into containers	Max. 2°C above carrying temperature
Optimum humidity	90%
Ventilation setting for containers	25 m³/hr
Storage life	1-2 weeks (mature green/turning) 1 week (ripe)
Climacteric / non-climacteric	Climacteric
Ethylene production	Very low
Ethylene sensitivity	High
Modified / controlled atmosphere	3%-5% O2; 2%-3% CO2 (see text)
Potential benefits	Reduced O2; reduced ripening, respiration and ethylene production. Increased CO2; delayed ripening
Availability
	On demand

Tomatoes

Harvesting and Handling

Tomatoes are subdivided into four main varieties depending on colour, shape, weight, size and cultivation method:

• Round (spherical) tomatoes: these are the most widely used, round, smooth, generally red tomatoes intended for fresh consumption.
• Beef tomatoes: these are larger than round tomatoes and are often also called ribbed tomatoes because of their shape. They are mostly used in the processing industry, but are sometimes also eaten fresh.
• Cherry tomatoes: the name points to the similarity in shape and size to cherries. Cherry tomatoes are of a higher quality than round tomatoes and beef tomatoes.
• Plum tomatoes: a thick-fleshed variety, low in seeds, again used both for fresh consumption and processing.

Tomatoes, which are picked when green, post-ripen subsequently so obtaining their red colour. Their typical aroma is unable to develop fully, however. The best time for harvesting tomatoes differs depending on their intended use (e.g. duration of transport). Outdoor tomatoes have higher nutrient contents than greenhouse tomatoes.

High quality fruit have a firm, turgid appearance, uniform and shiny colour, without signs of mechanical injuries, shrivelling or decay. Principle causes for postharvest losses are decay, external damage incurred during harvest and handling, and harvest at an improper maturity stage.

Cooling and Storage

Following commercial packing, tomatoes are routinely palletised and cooled to 20°C for ripening or to 12°C for storage. Optimal storage temperatures depend on the maturity stage of the tomatoes. Ideal conditions for ripening are 19°C to 21°C with 90% to 95%RH. Storage >27°C reduces intensity of red colour, while storage <13°C retards ripening and can lead to development of chilling injury, particularly in tomatoes at the mature-green stage. Red tomatoes can be stored at 7°C for a couple of days; tomatoes stored at 10°C were rated lower in flavour and aroma than those held at 13°C.

Tomatoes are climacteric and show a pronounced increase in respiration during ripening. The intensity and duration of the climacteric varies among fruit species. Respiration also varies with temperatures and atmospheric composition.

Tomatoes are chilling sensitive at temperatures below 10°C (50°F) if held for longer than 2 weeks or at 5°C (41°F) for longer than 6-8 days. Consequences of chilling injury are failure to ripen and develop full colour and flavour, irregular (blotchy) colour development, premature softening, surface pitting, browning of seeds, and increased decay. Chilling injury is cumulative and may be initiated in the field prior to harvest.

Controlled atmosphere considerations

Tomatoes can be stored under CA to extent product quality. The exact combination of CO₂ and O₂ varies among maturity stages and cultivars; but a satisfactory CA is 3% O₂ and 2% CO₂. Storage in 3% O₂ and 97% N2 extended postharvest life of mature-green tomatoes for 6 weeks at 13°C without development of off-flavours.

Storage disorders

Alternaria rot, Anthracnose, Bacterial soft rot, Bacterial speck, Blight, Canker, Chilling injury, Grey mould rot, Internal browning, Leaf spot, Splitting, Water rot, Watery soft rot.