CAPÍTULO 4 SELECCIÓN DE MERCADO
4.5 Elaboración de la MEFE
When fruit is to be processed and hygienically packed for long-term storage or for retail packs, a range of further steps needs to be taken. Fruit passing through the processing plant needs to be assessed for microbiological con-tamination, particularly for the presence of communicable human disease.
This is particularly important when the fruit is frozen, because microbiological contamination is often not sterilized but rather put into suspended animation by low temperatures.
To be able to monitor the microbiological status of fruit handled by processing plants that are freezing the fresh fruit, it is necessary to collect samples according to a regular testing program. These need to be placed onto various test media to show the presence or absence of pathogens.
52 H.K. Hall and T. Sobey
If fruit is to be block frozen or frozen in drums, care must be taken to ensure that temperatures in the center of the containers reach freezing temperatures before bacteria and fungi proliferate.
For production of individually quick frozen (IQF) raspberries there are a number of additional factors that are important. First, cultivars that are to be frozen for IQF production need to be fi rm and have good fruit quality, so that they will not collapse during the freezing process. Secondly, the cultivars must be suited to the freezing process used. Only cultivars having fruit with small drupelets can withstand freezing with the use of liquid nitrogen, whereas cultivars frozen using the fl uid bed technique are much less prone to freezing-induced bursting of drupelets, and they may have larger fruit and larger drupelets. Temperatures have to be carefully controlled so that fruit will not be damaged by mechanical impacts. ‘Willamette’ and ‘Meeker’ are both sensitive to temperatures being too cold, and if handled when fruit are at –20°C (–4°F), are subject to shattering; fruit will crumble and quality is signifi cantly reduced. At temperatures of –16°C (3°F) losses of IQF fruit quality through crumbling are much lower.
If raspberries are processed by cooking, heating, juicing or evaporation, temperature monitoring is also very important. Heat treatment is able to kill any contamination by microorganisms but the temperature and duration has to be suffi cient to destroy all bacterial and fungal growth. During the production of jams or preserves, it is necessary to constantly measure the temperature of the product to ensure that the heat treatment is suffi cient to destroy all microorganisms.
MARKET
The most important factor to consider in setting up fresh or process raspberry production is the market – its proximity, its requirements and what is required to excel in the marketplace. The key for maximum returns, no matter how the raspberries are presented for marketing, is to deliver exemplary quality that is better than competitors and to maintain this quality throughout the production season for fresh fruit and year-round for process products. Delivery of quality fresh market fruit has been the key to market development by Driscoll’s. They are quick to downgrade a product to a lesser brand if quality is lacking. Quality control is essential for every aspect of production and high-quality presentation is also obligatory. The best raspberry production operations have succeeded through the development of a robust consideration of marketing. Investment in raspberry production is worth considering when a market opening has been found and resources and expertise to deliver the high-end quality required for outstanding performance in that market have been acquired. A market analysis should include a detailed consideration of costs of production, including quality control, costs of packaging and
Site Selection 53
refrigerated storage, costs of shipping and transport, costs of marketing, and a study of expected returns and the eff ects of supplying extra product into the market.
Key to the ability to deliver quality are the cultivars grown, the environment in which the plants are to be grown, control of environmental factors through the use of protective structures, such as windbreaks, tunnels or greenhouses, the use of cover crops, mulching or weed mats, and mechanical or hand weed control. When ripe fruit have been produced, optimum management of harvest labor, timely picking and rotation through blocks, rapid and gentle transit to and through refrigerated storage to packing sheds, to the market, and eff ective presentation and rotation of stock in the marketplace are essential in order to maximize returns.
In the modern market, retailers are keen to have high-quality fresh produce in their stores to attract buyers of other less perishable products.
Fresh raspberries and other berries are key indicators to shoppers regarding freshness and quality as they are amongst the most perishable product lines.
Thus, delivery of a great product is a win–win–win solution for producers, marketers and retailers, and when quality control is well managed, all will benefi t from presenting high-quality fresh fruit to consumers.
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Plate 1.1.(a) Fruit of Rubus corchorifolius, from China. (b) Cane of R. corchorifolius, from China.
(Courtesy of Maxine Thompson and Judy Young.)
Plate 1.2. Fruit and leaves of Rubus parvifolius, from China. (Courtesy of Maxine Thompson and Judy Young.)
Plate 1.3. Fruit and leaves of Rubus sumatranus, from China. (Courtesy of Maxine Thompson and Judy Young.)
1.3 1.1a
1.1b
1.2
Plate 1.4. Fruit of Rubus niveus, from China. (Courtesy of Maxine Thompson and Judy Young.) Plate 1.5. Fruit and leaves of Rubus mesogaeus, from Hokkaido, Japan. (Courtesy of Yuri Ito.) Plate 1.6. Flower, young fruit and leaves of Rubus hawaiiensis, from Maui. (Courtesy of Joseph Postman.)
Plate 1.7. Fruit and leaves of Rubus strigosus, from South Dakota. (Courtesy of Michael Dossett.)
1.4 1.5
1.6
1.7
Plate 2.1. ‘Cascade Delight’, from the Washington State University breeding program at Puyallup, Washington, is a high-quality, large red raspberry for hand and mechanical harvesting. (Courtesy of David Karp, University of California.)
Plate 2.2. Black raspberry fruit separated from the receptacle. (Courtesy of The Ohio State University.) Plate 2.3. Comparison of raspberries and blackberries for oxygen radical absorbency capacity (ORAC). (Source: Oregon Raspberry & Blackberry Commission.) Note: The ORAC fl (µmolTE/g) analysis, which utilizes fluorescein as the fluorescent probe, provides a measure of the scavenging capacity of antioxidants against the peroxyl radical, which is one of the most common reactive oxygen species (ROS) found in the body. Trolox, a water-soluble vitamin E analog, is used as the calibration standard and the ORAC result is expressed as µmol Trolox equivalent (TE) per gram.
2.1 2.2
2.3
Plate 5.1. ‘Crimson Giant’ fruit in a typical 150 g (6 oz) clamshell container, harvested in the winter in Morocco for the European market. The bright red color is desired for today’s supermarkets and does not darken appreciably with storage. (Courtesy of C. Weber, Cornell University.)
Plate 5.2. Fully ripe fruit from ‘Caroline’. Note the darker color of the closest fruit, which is the ripest.
‘Caroline’ continues to darken with storage and is not suitable for larger wholesale markets. (Cour-tesy of C. Weber, Cornell University.)
Plate 5.3. The variety ‘Polka’ is somewhat dark but the shiny skin makes it acceptable for wholesale markets, although not preferred. Note the fruit in the upper right of the cluster is overripe and has turned a flat dark red color. (Courtesy of C. Weber, Cornell University.)
5.1
5.2 5.3
Plate 5.4. True yellow fruit color (a) differs from the amber or golden color (b), as demonstrated in the fruit of these selections from the Cornell University breeding program. (Courtesy of C. Weber, Cornell University.)
Plate 5.5. ‘Meeker’ is the standard variety for freezing and processing for much of this market. Note the darker red color and slightly conic shape. (Courtesy of C. Weber, Cornell University.)
Plate 5.6. ‘Jewel’ black raspberry exhibits the typical fruit shape and color of Rubus occidentalis. The unique flavor profile and health benefits of black raspberries have driven a resurgence of interest in the North American native. (Courtesy of C. Weber, Cornell University.)
5.4a
5.5
5.6
5.4b
Plate 5.7. ‘Tulameen’ produces large conic berries with excellent flavor that are highly sought after in the marketplace. Unfortunately, low temperature sensitivity, susceptibility to Phytophthora rubi, low yield and a high chilling requirement have limited its production for commercial markets. (Courtesy of C. Weber, Cornell University.)
Plate 5.8. Many modern varieties are susceptible to root rot caused by Phytophthora rubi, which is exacerbated by poor drainage. Resistance is polygenic in nature but is present in varieties such as
‘Prelude’, ‘Caroline’ and ‘Latham’. (Courtesy of C. Weber, Cornell University.)
Plate 5.9. Potato leaf hopper (Empoasca fabae) damage on developing primocanes of the variety
‘Polka’. Note the chlorotic, crinkled leaves that give the plant the appearance of virus infection.
(Courtesy of C. Weber, Cornell University.)
5.7 5.8
5.9
Plate 5.10. The large raspberry aphid (Amphorophoro agathonica) pictured and the similar small raspberry aphid (Aphis rubicola) are especially problematic in the spread of viruses that cause raspberry mosaic disease and others. (Courtesy of C. Weber, Cornell University.)
Plate 5.11. Symptoms of raspberry mosaic disease, which can lead to crumbly fruit and plant decline. This disease is spread by raspberry aphids and severely reduces yield and fruit quality.
(Courtesy of C. Weber, Cornell University.)
Plate 5.12. Verticillium wilt in black raspberry displays a characteristic flagging of primocanes with a bluish tinge. (Courtesy of C. Weber, Cornell University.)
Plate 5.13. The spine-free canes of ‘Joan J’ (a) are popular with home gardeners and pruning crews compared to those of ‘Crimson Giant’ (b) and most other varieties. (Courtesy of C. Weber, Cornell University.)
5.10 5.11
5.12 5.13a 5.13b
Plate 6.1. Propagation of ‘mother’ plants in the nuclear stock facility at The James Hutton Institute.
(Copyright The James Hutton Institute.)
Plate 6.2. In vitro propagation of raspberry. (Copyright The James Hutton Institute.)
Plate 6.3. Crumbly (left) and normal (right) fruit on raspberry. (Copyright The James Hutton Institute.)
6.1
6.2
6.3
Plate 6.4. Graft inoculation to Rubus occidentalis. (Copyright The James Hutton Institute.)
Plate 6.5. Sap indicators displaying symptoms after inoculation with tomato black ring virus (TBRV).
(Copyright The James Hutton Institute.)
Plate 6.6. Cane death from raspberry root rot infection. (Copyright The James Hutton Institute.)
6.4
6.5
6.6
Plate 6.7. Irrigation spray stake prevents back siphon. (Copyright The James Hutton Institute.) Plate 6.8. Black sclerotia on overwintered raspberry cane. (Copyright The James Hutton Institute.) Plate 6.9. Damage to foliage caused by feeding by raspberry leaf and bud mite. (Copyright The James Hutton Institute.)
6.7
6.8
6.9
Plate 7.1. Nodal sections of raspberry canes are cut to approximately 2.5 cm (1 in) in length, containing one axillary bud per nodal section. These are sterilized and placed in growth medium to induce elongation of the buds. (Courtesy of C. Weber, Cornell University.)
Plate 7.2. The nodal segments are trimmed after sterilization to remove tissue damaged by the bleach and to provide a fresh cut surface for uptake of nutrients from the growth medium. (Courtesy of C. Weber, Cornell University.)
Plate 7.3. Nodes are placed upright in the growth medium supported by the agar (0.8%) for elonga-tion. Note the red color from the Sprint®138 iron supplement. (Courtesy of C. Weber, Cornell University.)
Plate 7.4. Bud elongation and shoot development 10 days after placing nodal segments in the growth medium. The larger shoots will be ready for harvest within 5 days but can be left to elongate further. (Courtesy of C. Weber, Cornell University.)
7.1
7.2
7.3
7.4
Plate 8.1. Raspberry field treated with lime after plants exhibited poor growth. This lime will be relatively ineffective at increasing pH in the root zone. (Courtesy of M. Pritts, Cornell University.) Plate 8.2. Availability of soil nutrients varies with pH. (Courtesy of M. Pritts, Cornell University.) Plate 8.3. Raspberry plant exhibiting iron chlorosis on young growth that was induced by alkaline soil. (Courtesy of M. Pritts, Cornell University.)
8.2 8.1
8.3
© CAB International 2013. Raspberries (eds R.C. Funt and H.K. Hall) 55