6
Table grapes and refrigeration: fumigation with sulphur dioxide J.M. Harvey and M. Uota Le raisin de table et le froid: fumigations de dioxyde de soufre L'entreposage a long terme des raisins de table depend de la selection des fruits denues de moisissure, de procedes efficaces de refroidissement rapide et entreposage frigorifique, d'une prompte fumigation initiale avec de I'anhydride sulfureux (SO2), de desinfections periodiques avec des dosages corrects et une repartition uniforme du gaz. La repartition du gaz dans la chambre frigorifique ou dans le v~hicule de transport depend des caracteristiques de la caisse choisie, de rentassement dans la caisse, de rutilisation de palettes et, bien entendu, du systeme de circulation d'air employe. Tous ces facteurs sont extr #mement importants pour contr#ler la deterioration sans risquer des deg&ts par exposition excessive a SO2. La fumigation des produits emballes avec des melanges divers de bisulfite de soude ou de potasse donne une protection supplementaire aux expeditions en transit pendant plus de dix jours. Long-term storage of dessert grapes requires fruit which is free from rotting, efficient means of rapid cooling and cold storage, prompt initial fumigation with sulphur dioxide, and periodic disinfection with the correct dosage, uniformly distributed. The distribution of gas in the cold store or in the transport vehicle depends on the type of package used, the tightness of the pack, the use of pallets, and of course, on the system of air circulation employed. All these factors are very important in the control of deterioration, free from risk of damage due to exposure to excessive concentrations of S02. Fumigation of packaged produce with diverse mixtures of sodium or potassium bisulphite gives further protection to fruit in transit for more than ten days. The total grape growing area in California in 1976 was about 256 000 ha 22. Table grape varieties comprised about 26 600 ha. Production of table grapes amountedto about 364 million kg, which had a value of $86 million 23. During the past few years, peak cold-storage holdings of table grapes in the United States have reached about 91 million kg. The main storage season extends from August, through February, but stored or fresh table grapes are available during most months of the year. Long-term storage of table grapes is possible not only because of the improved refrigeration practices but also because of the development of effective fumigation practices to control decay17,46,53. Long-keeping varieties, ie Emperor, Ribier, and Calmeria, further contribute to the long- term storage of this commodity. M od ified atmospheres Modified or controlled atmospheres (CA) are not used commercially for table grapes. This storage method generally has little benefit for fruit with a non-climacteric respiratory pattern, such as grapes 1°. Research on storage systems combining CA with sulphur dioxide fumigation has shown that CA alone does not control decay, unless the carbon dioxide levels are increased or the oxygen levels are reduced to the point where physiological disorders Presented at IIR Commission C2, - OIV Commissions I-III, Paris France 1977/3 may 0ccur2,25, 48. Only fruit in treatments that included SO2 was in good condition after storage. Fumigation with SO2 also reduces the respiration rate of grapes during storage17,4~,53. SO2 Fumigation to control decay Sulphur dioxide fumigation is aimed primarily toward control of decay caused by fungi that are capable of growth at the storage temperatures used for grapes, -0.6 to O°C. The principal fungi causing decay of grapes are Botrytis cinerea Pers. ex Fr., Cladosporium herbarum Pers. and Alternaria sp.16, 47. The fumigation kills spores of these moulds that may be present on the surface of the fruit, but does not control established infections that may have occurred in the vineyard prior to harvesting13, 24. Such infections continue to develop within individual berries, during storage, but fumigation reduces the spread of decay from infected to adjacent berries and prevents the formation of 'nests" of mouldy berries. Consequently, after several weeks of storage individual berries may be found that have completely decayed inside and have mummified as a result of Botrytzs rot without having infected adjacent berries. Similarly, Alternaria may grow internally from the pedicel down into the fibrous tissues near the stem end of the berry, which results in a localized rot that may, in turn, cause the berry to separate or 'shatter' from the bunch. Volume 1 Number3 September 1978 01 40-7007/78/0103-0167 SO2.00 © 1978 IPC Business Press Ltd. 167

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Table grapes and refrigeration: fumigation with sulphur dioxide J.M. Harvey and M. Uota

Le raisin de table et le froid: fumigations de dioxyde de soufre L'entreposage a long terme des raisins de table depend de la selection des fruits denues de moisissure, de procedes efficaces de refroidissement rapide et entreposage frigorifique, d'une prompte fumigation initiale avec de I'anhydride sulfureux (SO2), de desinfections periodiques avec des dosages corrects et une repartition uniforme du gaz.

La repartition du gaz dans la chambre frigorifique ou dans le v~hicule de transport depend des caracteristiques de la caisse choisie, de rentassement dans la caisse, de rutilisation de palettes et, bien entendu, du systeme de circulation d'air employe. Tous ces facteurs sont extr #mement importants pour contr#ler la deterioration sans risquer des deg&ts par exposition excessive a SO2. La fumigation des produits emballes avec des melanges divers de bisulfite de soude ou de potasse donne une protection supplementaire aux expeditions en transit pendant plus de dix jours.

Long-term storage of dessert grapes requires fruit which is free from rotting, efficient means of rapid cooling and cold storage, prompt initial fumigation with sulphur dioxide, and periodic disinfection with the correct dosage, uniformly distributed.

The distribution of gas in the cold store or in the transport vehicle depends on the type of package

used, the tightness of the pack, the use of pallets, and of course, on the system of air circulation employed. All these factors are very important in the control of deterioration, free from risk of damage due to exposure to excessive concentrations of S02. Fumigation of packaged produce with diverse mixtures of sodium or potassium bisulphite gives further protection to fruit in transit for more than ten days.

The total grape growing area in California in 1976 was about 256 000 ha 22. Table grape varieties comprised about 26 600 ha. Production of table grapes amountedto about 364 million kg, which had a value of $86 million 23. During the past few years, peak cold-storage holdings of table grapes in the United States have reached about 91 million kg. The main storage season extends from August, through February, but stored or fresh table grapes are available during most months of the year.

Long-term storage of table grapes is possible not only because of the improved refrigeration practices but also because of the development of effective fumigation practices to control decay17,46, 53. Long-keeping varieties, ie Emperor, Ribier, and Calmeria, further contribute to the long- term storage of this commodity.

M od ified a tmospheres

Modified or controlled atmospheres (CA) are not used commercially for table grapes. This storage method generally has little benefit for fruit with a non-climacteric respiratory pattern, such as grapes 1°. Research on storage systems combining CA with sulphur dioxide fumigation has shown that CA alone does not control decay, unless the carbon dioxide levels are increased or the oxygen levels are reduced to the point where physiological disorders

Presented at IIR Commission C2, - OIV Commissions I-III, Paris France 1 9 7 7 / 3

m a y 0ccu r2 ,25 , 48. Only fruit in treatments that included SO2 was in good condition after storage. Fumigation with SO2 also reduces the respiration rate of grapes during storage17,4~, 53.

SO2 Fumigat ion to control decay

Sulphur dioxide fumigation is aimed primarily toward control of decay caused by fungi that are capable of growth at the storage temperatures used for grapes, -0.6 to O°C. The principal fungi causing decay of grapes are Botrytis cinerea Pers. ex Fr., Cladosporium herbarum Pers. and Alternaria sp.16, 47. The fumigation kills spores of these moulds that may be present on the surface of the fruit, but does not control established infections that may have occurred in the vineyard prior to harvesting13, 24. Such infections continue to develop within individual berries, during storage, but fumigation reduces the spread of decay from infected to adjacent berries and prevents the formation of 'nests" of mouldy berries. Consequently, after several weeks of storage individual berries may be found that have completely decayed inside and have mummified as a result of Botrytzs rot without having infected adjacent berries. Similarly, Alternaria may grow internally from the pedicel down into the fibrous tissues near the stem end of the berry, which results in a localized rot that may, in turn, cause the berry to separate or 'shatter' from the bunch.

Volume 1 Number3 September 1978 01 4 0 - 7 0 0 7 / 7 8 / 0 1 0 3 - 0 1 6 7 SO2.00

© 1978 IPC Business Press Ltd. 167

Page 2: Table grapes and refrigeration: fumigation with sulphur dioxide

800 ~ . . . . . . . . . . . . . . . . . . . . . . . . . .

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F i g 1 E f fec t o f c o n c e n t r a t i o n o f w e e k l y S O 2 f u m i g a t l o n s o n decay and bleaching of Thompson Seedless grapes stored 120 days 38

Fig. 1 Influence de/a concentration de fumigations hebdomadaires de S02 sur /a poumture et /a d#co/oratlon de raisins Thompson Seedless entrepos#s 120/ours 3~

Fumigation to maintain stem condition

Sulphur dioxide is also beneficial to the stems, causing them to bleach slightly and retain a light green or amber colour. Without fumigation, the stems darken, become unattractive, and may support growth of Blue Mould (Pen i c i l l i um sp.) 48. By helping to maintain stem and pedicel condition, fumigat ion reduces the tendency of berries to shatter or drop from the cluster during shipment ;9.

SO2 injury

Although fumigation with SO2 makes the long-term storage of table grapes possible, the gas may also cause various degrees of injury to the fruit.

Symptoms of injury are bleached, sunken areas that develop wherever the gas can readily penetrate the skin through breaks, wounds, or natural openings at the stylar or stem ends~6, 3s. Frequently the gas moves into the berry through the pedicel, causing a bleached, depressed area to develop around the point of attachment. The injury is accentuated if cracks occur in the skin around the pedicel; and in severe cases, the upper half of the berry may be affected. Some varieties, eg Flame Tokay, may develop sl ightly sunken, bleached pits scattered over the entire surface of the berry, when fumigated with SO2. However, this type of injury is not found on Emperor, Ribier, or Thompson Seedless unless the berries also have minute mechanical i nj u r i e s 16,39,42, 47 .

'Wetness' of table grapes that have been in cold storage for extended periods is another symptom of SO2 injury s9, This symptom is caused by the leakage of juice from the berries through microscopic mechanical injuries. The gas penetrates such injuries and damages tissues beneath them. As the exuded juice dries, the berry surface assumes a shiny, varnished, unsightly appearance, sometimes confused with freezing damage.

The balance between SO2 concentrations that control decay, but do not cause ~njury ~s delicate (Ftg. 1)

The selected concentrat ion of SO,, must be a compromise between that which will provide acceptable control of decay and that which will not cause excessive fnjury

Fumigation methods

Table grapes may be fumigated in storage, m the transport vehicle, or within individua! packages. Various combinations of these methods also may be used.

S t o r a g e f u m i g a t i o n In California, table grapes generally receive an initial 1% SO;- fumigation for 20 minutes, followed by weekly applications of 0 25% SO2 for 20 to 30 minutes~4, 4647

At the end of the fumigation treatment, the SO~' is removed from the storage room either with an exhaust fan or by dissolut ion of the gas in the water or brine spray used in the refrigeration system

Other factors that may may influence the selection of a particular concentrat ion of SO~ are the relative humidity in the storage room32, 37, the decay potential of the fruit ~3,~5 aar movement within the room and the type of package used 33.

The relative humidity in cold storage rooms designed for grapes is kept h~gh (90 to 95%) to reduce desiccation of the fruit ~s. These high levels of relative humidity increase the amount of SO:, absorbed by packaging materials and require adjustment in the dosage to compensate for the SO2 removed from the free arr space around the grapes32, 33 However, if grapes are packedtn polystyrene foam boxes little or noSO? sremoved during fumigation and the total amount of SO:~ needed is less than that for grapes packed in wooden boxes (Fig. 2),

High moisture condit ions also increase the toxicity/ of SO2 to the spores of Botrytis cinerea and Alternana spp.3, 4. At a given dosage of SO~,, fumigahon of Bo t ry t / s spores at 20°C was 20 hrnes more effective at 96% RH than at 75% RH. Similarly. near-saturated atmospheres increased the sensitivity of Alternaria spores to SO:~. The importance of maintalning high RH during the ~nhtial SO2 fumigation to kill spores on the surface of fruit is readily apparent.

Some adiustment in the dosage of SOs ~s sometimes made for grapes with a high decay potential. Although storage decay can be accurately forecast for individual lots of table grapes~3,15, the primary value of the forecast ~s to guide the marketing of the crop, ie store only sound lots and quickly ship lots with a htgh decay potential. However, the forecast is also a signal to re-examine the SO2 dosage used in lots with a high decay potential. This practice ~s sometimes fol lowed by commercial operat, ors, bu~ ~hose wh,:)

168 International Jo:~r,qat ol Retrigeraho~

Page 3: Table grapes and refrigeration: fumigation with sulphur dioxide

employ it must be prepared to accept possible increases in the level of SO2 injury and only slight reduction in the spread of decay from field-infected fruit to sound fruit.

The air velocity required for uniform and adequate penetration of SO2 into grape packages is much higher than that needed to maintain proper temperatures in storage33,37. 47. The type of package and the method of stacking also determine the air velocity needed to assure proper gas penetration. Nelson and Richardson reported that a velocity of 1 5 m min -~ was needed for grapes in standard boxes with liners, but that 23 m min -~ was necessary if paper curtains or cluster wrapswere used. Obviously, package venting, design, palletization, and many other factors would affect the requirements for air velocity in the fumigation chamber.

The foregoing discussion of storage fumigation was based primarily on practices followed in the United States. Fumigation procedures in other countries, such as South Africa, include the continuous exposure of table grapes to low concentrations of SO2 in storage12,19,2o, 21 . Automatic control equipment has been developed to maintain storage atmospheres that contain 20 ppm SO2 over periods of three or more months. Grapes stored in such an atmosphere absorb 10-15 ppm SO2. More recentwork2, 9 has shown that SO2 concentrations of 7-10 ppm in the room atmosphere provide satisfactory decay control without excessive SO2 injury 8.

Transport fumigation Table grapes are frequently fumigated in rail cars, trucks, or van-containers. Generally the grapes receive an initial fumigation and are precooled before having been loaded in the transport vehicle. Consequently, the concentration of gas used on this kind of fumigation usually is equivalent to an interval gassing in storage, or 0.25% SO2 for 20 to 30 minutes. Uniform distribution of the gas in the transport vehicle is essential to prevent over-exposure (injury) of some parts of the load and under-exposure (ineffective decay control) of other parts 6,42,46,50. Without a fan to mix and distribute the gas, boxes on the periphery of the load receive excessive exposure to SO2 and those deep within the load receive insufficient amounts (Fig. 3). With a supplemental fan, the gas is uniformly distributed throughout the load (Fig. 4). In mechanically refrigerated transport vehicles, the fans used to circulate refrigerated air should be run continuously during the fumigation (Fig. 5). In such vehicles, it is important to ventilate the car by opening the doors at the end of the fumigation period. Rail cars or van-containers that are equipped for use with modified atmospheres in transit are tightly sealed and when such vehicles are used for SO2 fumigation of grapes, the gas is retained for long periods (Fig. 6). In export shipments from California, the gas is applied at shipping point and is sometimes left in the van until it arrives at the port for loading aboard the container ship. This practice has resulted in

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Air surrounding lug box

Centre of wrapped cluster in middle of expended polystyrene box

I I I I I I 0 5 I0 15 20 25 30

b Time, rain

Fig. 2 Effect of packaging material on the concentrat ion of SO2 in a grape box a - - wood, b - - expanded polystyrene

Fig. 2 Influence du mat#riau d'emballage sur la concentration de S02 dans la ca~sse de raisins, a - bois, b - polystyrene expans#

~3

2~

Bunker I f a n s on

I ~ . [ • Top of load

1.2 ~- / , ~ e ° D~o(~;::;:cC:rntre of box F / / II ~ Quorterlength-air

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0 8 i i • i i • Bunker- centre of box

' ~ / / //[Bunker o L// • i Bunker

0 3 6 9 12 15 18 21 24 27 30 33 Time, min

Fig. 3 Concentrations of S02 in an ice-refrigerated rail car wi thout a supplemental brace fan so. Gate load 1 050 lugs emperor grapes, 2.27 kg sulphur dioxide applied at doorway

Fig. 3 Concentrations de S02 dans un wagon r#fng#rant sans ventilateur supp/#mentaire entre los empilages de caisses 5o. C hargement : 1 050 cageots de raisins Emperor, 2, 2 7 kg de dioxyde de soufre appliques a I'entr#e

excessive SO2 injury and indicates a need to ventilate the van before it leaves the shipping point.

In-package fumigation Various formulations of SO2-producing compounds have been developed for in-package fumigation of table grapes. This

36

Volume 1 Number 3 September 1978 169

Page 4: Table grapes and refrigeration: fumigation with sulphur dioxide

12 I q oe Top of Iood

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a Quorterlength - air o ~ • Quorterlength-centre of box

0 .8 o Bunker-ok Bunker- centre of box

-

~ 0 6

0 4 Bunker ns on

O 3 6 9 12 15 18 21 24 27 30 33 36

Time, min

Fig. 4 Concentrat ions of SO2 inan~ce- re f r ige ra tedra i l ca rw~th a supplementa l brace fan 5o. Gate load 970 lugs emperor grapes, 2.27 kg sulphur d iox ide appl ied at doorway. Supplemental brace fan directed upward and operat ing cont inuous ly

Fig 4 Concentrat ions de S02 dans un wagon retmgerant avec ventHateur supp/ementaire entre/es empi/ages de caisses 5° Chargement ." 9 70 cageots de razsins Emperor, 2, 2 7 kg de dioxyde de soufre appl iques ~ I 'entree Ventdateur supplementa i re entre/es empi/ages, dimg# vers /e haut el fonc t ionnant cont inue/ /ement

1.2 E o Doorwey- oir © Doorwoy - centre of box

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o . 6 ~ / ®

I I I I I I I I I I l ] I [ I J I I 1 1 L I I I I I I I I ~ L ) ~ J

0 3 6 9 12 15 18 21 24 27 30 33 36 Time , mm

Fig. 5 Concentrat ions of SO2 inamechan i ca l l y r e f r i ge ra ted rad car with cont inuous operat ion of car fans 5°. Gate load 1 125 9.06 kg - lugs emperor grapes, 2 .50 kg sulphur d iox ide apphed at doorway. Bunker fan operat ing cont inuous ly

Fig. 5 Concentrat ions de S02 dans un wagon fmgorihque avec fonc t lonnement cont inu des ventHateurs du wagon 5° Chargement . I 125 cageots de 9, 06 kg de raisins Emperor 2, 5 kg de dioxyde de soufre appfiques ~ I'entree. VentHateur du wagon fonc t ionnant eont inue/ /ement

technique is used primarily for shipments that may be en route for two or three weeks or more, and that cannot be 'room" fumigated at intervals during transit.

Since the early 1 930's, the sawdust export chest for Calfornia table grapes has been fumigated with SO~ by about 5 g of sodium bisulphite added when the sawdust is vibrated into the package 4°. This procedure distributes the bisulphite evenly through the sawdust. As the chemical reacts with moisture it gives off SO~. The rate of SO2 evolution is dependent upon the amount of moisture present. Too much moisture causes too rapid a release of the gas so that the fruit is bleached and no gas is left for the latter part of the transit period.

In South Africa, a system was developed ~r ~, wn~c~ solutions of sodium bisulphite or potassium metabisulphite were sprayed on the 'woodwooi ' (excelsior) packing of grape boxes to con!rol decay 44 The pH of the solution was adjus[ed to about 5.0 to control the rate of SO2 liberation from the solution 45. AbOut 20 ml of a 40% soiu[ion was applied just before the packed boxes were lidded 3~

Tablets or packets incorporating various matenals, eg al luminium sulphate or silica gel, with sodium bisulphite have been effective ~n control l ing the release of SO2, and have been particulariv effective for decay control when used in combination with polyethylene box l inersS,2°,36, 434~- ~'! ~2

These early systems for ~n-trans~t fdmigat~on have gradually given way to newer liquicl or solid SO:~ generators that are easier to apply and ar{~ compatible with modern packaging systems

The liquid SO2 generators consist of small poly- ethylene bags that contain solutions of potassium metabisulphite ~1 Varying the thickness of the poly- ethylene bag controls the rate of release. Atwo- stage release capability ~s achieved Oy olacJng bags of two different thicknesses wlthrn the E)acKages of table grapes

Two-stage, solid-S02 reJease generators containing sodium b=sulphite between layers of ooivethvrene- coated oaDer are w=delv used for exoor~

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12

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Ftg. 6 C o n c e n t r a h o n s o f S O 2 ~ n a n m t e r . n o d a l v a n conta iner with cont inuous operat ion of fans. - . . . . . . . In middle of expanded polystyrene box stacked ~n centre of pallet, second row from from '

in air channel adjacent to box, ~n centre of pallet, - ...... ~n middle of expanded polystyrene box, stacked m second layer from top of pallet, second row, - - ~n air channel adjacent to box, ~n centre of pallet, - - - ~n middle of expanded polystyrene box, stacked ~n centre of pallet, second row from rear, ~n a~r channel adjacent to box, in centre of pallet

Fig. 6 Concentrat ions de S02 dams un comter~eur ~mtermodai avec /onct lonnernent contmu des vent#ateurs . . . . . Au ml//eu de /a ca/sse de po/ystyr#ne expanse p/acee au centre de/a pa/ette, 2eme rangee b part / r de/'avan[, ., dams fe passage d'alr vo/s/n de/a ea~sse, au centre de la pa/ette, --- - au rrnlteu de la crosse de po/ystyr#ne expanse, placee dans /a 2eme couchP a par t / r du haut de la pa/ette, rangee centra/e, -- dams le passage d'a/r vo/sm de la calsse, au centre de/a pa/ette, . ,Ju mff~eu de/a ca/sse de po/ystyrene expanse, placee au centre de la pa/ette, 2eme ramgee a par t l r de ~'arm#re dams'/e passaqe d'a/r vo/s/n de la ca/sse, au centre de la f~alette

170 International Journal of Refrigerat~or.,

Page 5: Table grapes and refrigeration: fumigation with sulphur dioxide

shJpments1,7,11,26,27,28,29,20.21,34, 35. The generators are placed at the top and bottom of the box when the grapes are packed and provide protection of the fruit for as long as three months. The generators may be used either in unvented boxes or in palletized, vented boxes with a polyethylene pallet cover to retain the gas. If, during shipping or distribution, the_grapes are exposed to high temperatures, the covers should be removed to prevent excessive buildup of SO2 and injury to the fruit 3°. Injury also may occur if grapes, packed with S02 generators, receive an additional fumigation in the transport vehicle.

Conclusions

Sulphur dioxide fumigation is essential to the marketing, transport, storage, and export of table grapes. Fumigation methodology has progressed from simple techniques involving the burning of sulphur in a closed room or rail carto rather elaborate devices for monitoring and controll ing levels of SO2 in storage, or for controlled release of S02 in packages during shipment. This improved technology has contributed to the expansion of the table grape industry and to the availability of this f ru i t in the market p lace dur ing most months of the year.

R eferences 1 AnonTheB/ueAnchor48(1971)425 ,27 2 Combrink, J.C., Ginsburg, L. The Deciduous Fruit Grower

22(1972)8, 186-189 3 Couey, H.M. Phytopatho/ogy55 (1965) 525-527 4 Couey, H.M., Uota, M. Phytopatho/ogy51 (1961 )

815-819 5 Fideghelli, C., Monastra, F. R/v V/tic Enol Coneghano

(1968) 10 6 Gentry, J.P., Nelson, K.E. AmJEno/Vmc 14 (1963) 2, 86-93 7 Gentry, J.P., Nelson, K.E. AmJEno/Vit lc 19 (1968) 1,

70-81 8 Ginsburg, L. The Declduous Frult Grower15 (1965) 7,

192-199 9 Ginsburg, L., Combrink, J.C. The Deciduous Fruit Grower

19(1969)6. 155-159 1C Grierson, W, Proc Nat Controlled Atmosphere Res Confr

Mich State Univ Hortic Rept 9, 77-79 I 1 Guelfat-Reich, S., Safran, B., Gattenio, S., Metal, N. Vltls

14(1975) 220-227 12 Hall, E.G.CSIRO Food PreservQ 15 (1955) 3.42-44 13 Harvey, J.M. Phytopatho/ogy45 (1955) 229-232 14 Harvey, J.M. Phytopatho/ogy46 (1956) 690-694 15 Harvey, J.M. US DepAgric Marketing Res Rep 392 (1960)

12pp 16 Harvey, J.M., Pentzer, W.T. US Dep Agric Handbook (1960)

189 (37 pp) 17 Jacob, H.E. CahfAgrExp Sta Buff (1929) 471 (24 pp) 18 Lutz, J.M., Hardenburg, R.E. US DepAgric Handbook

(1968) 66 (94 pp) 19 Malan, H. Farrmng m S Atr 29 (1954) 335, 157-159 20 Malan, H. Farrmng in SA l t 30 (1955) 349,231 -232 236 21 Marais, P.G. S Afr Dep Agrlc ScJ Buff ( 1952 ) 322 ( 10 pp) 22 McGregor, R.A., Cain, M., Seibert, J.C. 1976 Grape

Acreage Survey, Calif Crop and Livestock Rep Ser (1977) (3 pp)

23 McGregor, R.A. et al Annual Fruit Summary, Calif Crop and Livestock Rep Set (1977) (4 pp)

24 Nelson, K.E. ProcAm Soc Hortic Sci71 (1958) 183-189 25 Nelson, K.E. Proc Nat Controlled Atmosphere Res Confr

Mich State Univ Hortic Rep (1969) 9, 77-79 26 Nelson, K.E. B/ue Anchor 47 (1970) 4.9 11-13 27 Nelson, K.E., Ahmedullah, M. Am J Eno/ Vmc 31 ( 197 O) 2,

70-77

28 Nelson, K.E., Ahmedullah, M. Am J Eno/Vmc 23 ( 1972) 1, 39-42

29 Nelson, K.E., Ahmedullah, M. Am J Eno/VitlC 23 ( i 972 ) 2, 78-85

30 Nelson, K.E. Ahaedullah, M. Am J Eno/Vmc 24 ( 1973) 2, 75-80

31 Nelson, K.E. Ahmedullah, M . A m J E n o / V m c 2 7 (1976) 2, 74-~9

32 Nelson, K.E., Baker, G.A. Am J Eno/Vmc 14 (1963) 1, 13- 22

33 Nelson, K.E., Baker, G.A., Gentry, J.P. Am J Eno/Vmc 15 (1964) 2, 93-102

34 Nelson, K.E., Gentry, J .P.AmJEno/Vmc 17 (1966) 4, 290-301

35 Nelson, K.E., Gentry, J.P. The B/ueAnchor45 (1968) 2. 33-34 36-37

36 Nelson, K.E., GiMburg, L., de Swardt, G.H. The DeciduousFru~tGrower19 (1969) 10, 313-320

37 Nelson, K.E., Richardson, H.B. ProcAm Soc Hortic Sci 77 (1961) 337-350

38 Nelson, K.E., Richardson, H.B. Phytopatho/ogy57 (1967) 950-955

39 Nelson, K.E., Tomlinson, F.E. Proc Am Soc Hortic Sci 71 (1958) 190-198

40 Pentzer, W.T. The B/ueAnchor 16 (1939) 7.2 41 Pentzer, W.T., Asbury, C.E., Hsmner, K.C. Proc Am Soc

Hortic Sci 30(1933) 258-260 42 Pentzer, W.T., Bratley, C.O., Tufts, W.G. US Dep Agr

Mimeo Rep (1942) (11 pp) References Page 11

43 Rattray, J.M. S Afr Dep Agric and For, Low Temp Res Lab Ann Rep 1938-39 (1940) 48-60

44 Reynake, J., du Plessis, S.J. Farming in S Afr Fruit Res Ser (1943) 19 (3 pp)

45 Reyneke, J., Pieget, J.E.H. Farming in S Afr (1952) 27, 477-479

46 Rose, D.H., Pentzer, W.T. The B/ue Anchor 24 ( 1947 ) (4). 5724

47 Ryall, A.L., Harvey, J.M. US Dep Agric Handbook (1959) 159 (46 pp)

48 Uota, M. ProcAm Soc Hortic Sci69(1956) 250-253 49 Uota, M. ProcAm Soc Hortic Sci 70 (1957) 197-203 50 Uota, M., Harvey, J.M. US Dept Agr Marketing Res Rep

(1964) 642 (23 pp) 51 Van Der Plank, J.E. S Aft Dep Agr and For, Low Temp Res

LabAnn Rep 1937-38 (1939) 76-78 52 Van Der Plank, J.E., Van Wyk, G.F. S Afr Dep Agr and For

LowTemp Res Lab Ann Rep 1938-39 (1940)43-47 53 Winkler, A.J., Jacob, H.E. Calif Agr Exp Sta Hilgardia 1

(1925) 107-131

Dr John M. Harvey received his PhD in plant pathology at the University of California,

Berkeley, USA in 1950. He has been in charge of the USDA, Market Quality and Transportation Research Laboratory at Fresno, California since 1956 and has specialized in the storage and refrigerated transport of perishable fruits and vegetables, He has a particular interest in the identification and reduction of postharvest losses in these crops.

Dr Masami Uota recewed his PhD in pomology at

Cornell University, Ithaca, New York, USA in 1950 He was horticulturist at the Fresno Laboratory from 1951 until his death in July 1977. Dr Uota was noted for his expertise in the storage of fruit, and in the handling and storage of cut flowers. He developed techniques for C .A. storage that are widely used in the laboratory and also commercially.

V o l u m e 1 Number 3 Sep tember 1978 1 7 1

Page 6: Table grapes and refrigeration: fumigation with sulphur dioxide

Visual display units provide one of the fastest means of interaction with a computer, and they are being employed in industry in ever-increasing numbers. Their applications are wide-ranging, including airline-seat reservations, stock-control systems, information retrieval, stock-market and insurance quotations, text editing and information updating. Yisual Display Units is based on a tutorial seminar organised by the British Computer Society. The book is intended for computer users who already employ VDUs or plan to use them to enhance their system. It will be of equal value to management in their basic decision-making, and to the systems analysts and data-processing managers who put those decisions into practical effect.

CONTENTS Foreword by Cecil Marks, Chairman, British Computer Society Introduction Review and trends (Derrick Grover , National Research and Development Corporation) Introduction - applications - technology - communicat ions - interactive method~ - systems - security - software - the intelligent ter- minal - trends The technology of visual display units ( lorwerth Jones, Cossor Electronics) The m o n i t o r - linearity - focusing - the data store - the character generator - the keyboard - communicat ion - inlerl~cc - the whole assembly - the power supply - summary Communications (Peter Burton, Computer and Systems Engineering Limited) In t roduc t ion - se r i a l transmission of digital d a t a - n e t w o r k con f igu ra t ions -communica t ion lines and scrvice~ communicat ion ~ terFace standards - information flow control - outlook Intelligence (lan Richards, Ferranti) Introduction - the reasons for intelligent terminal systems - the structure of intelligent Icrminal systems - the pOWer ~i terminal c e ~ t ro l l e r s - the uses of in te l l igence- the user interface for a typical application - the future Software (Brian Larbalestier. Logica) Layered ~,oftware - terminal handling - formatting and field definition aids - multitasking software Human factors in the design of VDUs (Roy Gladman, IBM) Introduction - the display unit - the keyboard - the display work station Human factors in the use of VDUs ( T o m Stewart, Loughborough University) The m a n - c o m p u t e r p a r t n e r s h i p - m a n - c o m p u t e r d i a l o g u e s - int roducing the VDU into the office e n v i r o n m e n t - pt~ssiblc pi~- falls - conclusions Summary Glossary Index

The book also includes an extensive glossary of VDU terminology 215 x 155ram/vi i i + 207 pages / i l lus t ra t ions /g lossary/ index/c lo th / ISBN 0 902852 65 5 Price £7.00 net ($14.00)

This book is available now from: Books Sales Dept. CSIB

IPC Science and Technology Press Limited, IPC House, 32 High Street, Guildford, Surrey, England GUI 3EW

Telephone: 0483-71661 Telex: Scitec Gd 859556

172 Internat~o,nai Jo,.Jrnai of Refr~ger