CA ensures fruit and veg all year round all over the world

Thanks to developing technologies such as Controlled Atmosphere (CA) container transport for perishables, supermarket shelves can source fruit and vegetables from around the world, ensuring availability of good quality fruit regardless of season. Ongoing research continues to determine diverse and new benefits of CA. Controlled atmosphere is the control of the chemical composition of the atmosphere surrounding a commodity by the continual addition or removal of gases. The function of the controlled atmosphere system is to increase and maintain the nitrogen concentration, remove and maintain the carbon dioxide, decrease the oxygen level, remove ethylene as it is produced and maintain relative humidity. It should be considered as a useful supplement to proper temperature and humidity management. Controlled atmosphere: l Reduces respiration and ethylene production rate (Climacteric fruit i.e. fruit which ripens after harvest, is induced to ripen rapidly and irreversibly by exposure to ethylene, which is a ripening hormone) l Retards senescence, which is associated with softening and other compositional changes l Alleviates physiological storage disorders such as chilling injury on avocados and scald on apples l Retards pathogens l Assists with insect control. For this reason, CA can be used for short- and long-term storage, benefiting everyone in the supply chain. An important advantage is that the extended shelf life enables exporters of fruit and vegetables to hold back their products until later in the season when prices are more attractive or shipping is more convenient. Certain varieties of avocados such as Hass can be stored for up to five months, certain varieties of pears such as PackhamÕs Triumph can be stored for up to nine months, and apple varieties such as Golden Delicious for up to 10 months. This works both ways as, for example, avocado traders in Europe prefer the fruit to arrive at their warehouses hard and unripe, as an extended shelf life gives wholesalers and retailers more time to sell the fruit. South African commodities that move in CA include avocados, apples, pears and plums. Due to the increased awareness of CA, as well as the increase in global competitiveness for high quality and year round supply, itÕs an expanding market. Already we are looking at developments where the more cost-effective use of sea transport can substitute for air transport. Future advances may include oxygen control measuring alcohol concentrations, possibilities for variable temperature regimes, gas concentrations and mineral additions to the humidity injection system, or the addition of calcium by sublimation, all opening the door to new commodities being shipped under CA.