TOMATO farmers can prolong the shelf life of their produce if they harvest them at a mature green stage, mix them with rice straws, and store them in plastic sacks or paper boxes.

This technique has been proven to be very profitable during off-season months when there is limited supply of tomato.

In a test conducted by researchers Maura Luisa S. Gabriel, Marissa I. Atis, Aleta E. Dumaoal, and Zenaida H. Esteban, tomatoes stored using the improved technique will last for more than two months with extremely low percentage of rotten fruits. The containers, however, should be placed on an elevated floor with good ventilation and with ambient temperature which ranges from 26-34 degrees celsius.

Places with ambient temperatures are those inside an ordinary store house with nipa or cogon grass roofings built under shady areas.

The researchers said this improved storing technique could give farmers a substantial return of investment (ROI) of 129 percent per 10 kilos of tomato, higher by almost 50 percent than the traditional method practiced by tomato growers and traders who store their fruits in bamboo crates, plastic sacks, and paper boxes without rice straws.

In March to April when harvest floods the local markets, the price of tomato in Ilocos Norte falls to a farmgate price of P15 per kilo. Farmers who do not practice this improved storage technique would not even want to harvest their ripe tomato because they would spend more on the wages of the harvesters than the price of their produce.

With this improved technique, however, farmers could prolong the shelf life of their tomatoes and could sell them during off-season months when the farmgate price is pegged at P60- P80 per kilo.

The experiment

The researchers tested the other conventional materials and method of storing tomato by farmers in Brgy. Quiling Sur, Batac City who were either tomato growers or fruit traders. The results were compared with the new recommended technique.

Usually, the farmers utilize ordinary bamboo crates and baskets, paper boxes, plastic sando bags, and plastic sacks as packaging materials, and old newspapers as linings and coverings of the containers. This traditional method, according to the researchers, have contributed to the increased rotting percentage of the harvest, thus causing heavy losses, especially if the fruits are not sold less than one month after harvest.

Farmers who stored their tomatoes in the traditional way found most of their produce rotting after two months.  Fruits that rot earlier than expected affected those that were ripening, while many also shriveled because of moisture loss.

The highest percentage of rotten fruits, which was about 61.33 percent, was observed among the fruits stored in ordinary crates alone, while the lowest, 3.75 percent, was observed in paper boxes with rice straws.  

“That’s why we advise farmers to mix the tomatoes with rice straws before putting them in the recommended packaging containers and provide these with proper aeration and minimum physical contact,” the researchers said.

Storing tomatoes

In Ilocos Norte and some parts of the Ilocos region, storing mature green tomatoes has become a perennial practice by farmers and traders who believe that they could derive substantial profits, especially if the fruits are still fresh after several months of keeping them. However, with their own traditional techniques, farmers usually realize low profits.  

Most farmers even store their tomatoes in plastic sacks and bamboo crates used to carry grass for their confined or tethered livestock, thus increasing the harvest’s risk of being contaminated with pests, fungi, and other harmful organisms left inside the crates. Then, they hang the packed fruits, either in horizontal or vertical position, in open space inside their makeshift warehouses with roofs made of galvanized iron.

To avoid this, farmers should clean the plastic sacks and paper boxes before using them, and check whether the fruits are free from damages caused by pests and diseases.

Prior to storing, rice straws must be collected from threshed panicles in rice paddies. These should be mixed with the harvested mature green fruits at about 2-3 centimeters thick.