
A meander along South Africa’s CA storage road
By Richard Hurndall.
Following the first commercial Controlled Atmosphere (CA) cold storage room in Kent, UK in 1929, Molteno Brothers built a 7-room complex in 1934, each room holding about 6000 wooden lug boxes of apples. This complex was enlarged to 127 000 lugs capacity, making it one of the largest CA installations in the world at the time. It was initially impossible to make these rooms fully gas-tight, but they achieved storage conditions of 3.3 °C, 8% O2 and 5% CO2. Apparently, the operator became quite breathless when he went inside to change lime, examine the fruit, and inspect the ammonia coils!
Nevertheless the marketing of Ohenimuri apples could be extended to August, and Winter Pearmain to September. This was followed in 1936 by a 40 000-lug capacity 4-room complex by the Elgin Fruit Company (now Two-A-Day). With the advancement of Regular Atmosphere (RA) storage in the 1950s and 1960s, first using central ducts for air circulation, and later false ceilings, there was a great improvement in the out-turn of fruit from RA storage, and CA storage consequently took a back seat.
While the rest of the world steadily increased their CA capacity, it was only in the late 1970s that local interest was rekindled in CA storage. In 1979, a delegation comprising growers, cold-store operators, consulting engineers, and post-harvest technologists visited CA storage facilities in Europe, Israel, UK, and USA. They returned with a vast amount of information and the latest technology, which helped considerably to rapidly establish CA storage as a viable enterprise in South Africa. The first exports of fruit from CA stores took place in 1983. CA capacity increased rapidly, and by 2000, the capacity had increased to over 260 000 tonnes.
A technical working group was established in 1978, and subsequently became the CA Storage and Post-harvest Group in 1980. The group was taken under the wing of the SA Apple and Pear Producers’ Association in 1983. At the time of my introduction into the industry in 1983, John Findlay was the enthusiastic chairman of the group. John’s mantra was that members were there to share their mistakes, as that was the quickest way to learn. Subsequent chairmen included Albert Schultz (Ceres Koelkamers) and Piet van Bodegom (Kromco). The CA Group used to meet twice annually, once in the production regions where the latest technology was viewed, and an AGM in November at Infruitec where the fruit of various CA storage trials was displayed. Research was always a strong focus of the group, and to this end SAAPPA donated experimental chambers to the Agricultural Research Council (8 in 1982 and a further 4 in 1988; capacity 15.6 m3).
Under SAAPPA’s auspices, this body issued a quality assurance mark in the form of a CA label. The SAAPPA CA label guaranteed that the fruit was packed and stored under optimum CA storage conditions. It was issued only to registered members of the CA Group whose CA stores had passed an annual evaluation and had been registered by the PPECB in accordance with the Perishable Products Export Control Act, 1983 (Act no. 9). The annual evaluation ascertained whether CA rooms of members complied in all respects with the recommended CA storage conditions under which apples and pears should be held to attain a product of high quality. The evaluations were conducted by Bertie Truter, and subsequently Kobus van der Merwe of the Agricultural Research Council.
If the CA stores observed the relevant criteria, permission was granted for the use of the CA label. This was used in the form of a label, rubber stamp or printed on the carton and the wording “Guaranteed packed and stored according to SAAPPA Controlled Atmosphere Regulations.” SAAPPA is the registered patent holder of the CA mark. Any reproduction was an infringement of the copyright.
The design allowed for an individual number, which was an inspection number given to all registered producers, to be printed on the label. The inspection number facilitated the follow-up of transgressors. The annual inspections, of course, led to much rivalry between organisations, as the CA trophy was awarded to the best storage operation at the annual AGM meeting. These procedures led to an extremely high standard of safety and operational efficiency, which was probably unique in the world. Apart from the sharing of information, one of the major outputs of the CA Group was the CA Manual, available on the Hortgro website.
With the advent of deregulation in 1997, the CA Group was disbanded. Consultants now conduct inspections of CA stores upon request. Marketing operations now have their own internal quality management systems and market their fruit under their respective brands.
Dynamic Controlled Atmosphere (DCA) experts were brought in in the intervening years to facilitate the introduction of this technology into the industry. This included the co-founder of the DCA technology, Dr Robert Prange of Canada’s Agriculture and Agri-Food Research and Development Centre, and Dr Angelo Zanella (Laimburg, Italy), the foremost implementer of the DCA technology on a large scale.
The CA Group was revived in 2015, under the auspices of the Packhouse Action Group, and an annual meeting is held to give research feedback to the industry, as well as to showcase new technology. A local CA operator’s tour was held in the EGVV region in 2016 to view 2 different CA storage technologies. SAAPPA, now Hortgro Pome, donated CA research equipment of 3 CA suppliers to Stellenbosch University in 2018, to increase the research capacity in the industry.