VALUE CHAIN #

 

Commercial Postharvest Handling of Potatoes (Solanum tuberosum)

The potato tuber is a shortened, enlarged, underground stem. Eighty percent of the potato tuber is water, with the remainder being carbohydrate, protein, ash, and fat. Potatoes are living organisms that respire, using oxygen and giving off carbon dioxide, moisture, and heat.

 

Harvesting

Three key conditions should be met in order to minimize harvest injury: 1) apply chemical vine killer two weeks before harvest, 2) harvest when soil conditions are dry, and 3) avoid harvesting in the late fall, when soil and air temperatures are below 45 degrees F. Killing vines before harvest allows them to dry thoroughly and allows time for pathogens to die, reducing the chances of transporting them into storage. It also allows for tuber skin maturation, reducing skinning and bruising. Harvesting when soils are dry decreases bruising due to soil clods and transport of soil into storage where it can block air circulation through the potato pile. Harvesting at temperatures below 45 degrees F will injure potatoes more than at higher temperatures. Avoid harvesting when temperatures are above 60 degrees F to minimize water loss and shrinkage.

One of the biggest problems to be controlled during harvest and handling is bruising. When bruising occurs in the early stages of postharvest handling, the potatoes get nicked and become breeding grounds for microorganisms, allowing them to spread rapidly and cause serious losses. To prevent bruising, inspect and adjust harvesting equipment frequently. Reduce drop heights, bouncing, and rolling by padding impact areas and adjust contact surfaces.

Tubers are usually conveyed from the harvesters into dump trucks or bins. When transporting tubers from the field to the packing shed, cover the load with a tarp to reduce exposure to high temperatures and sunlight. Exposure to light can cause greening.

If harvesting by hand, be careful not to nick potatoes with your digger. Carefully transfer tubers into bins, shade bins, then transport to your packing shed.

After harvest, potatoes are dormant for 6 to 12 weeks, depending on variety and storage temperatures. After the dormancy period, potatoes may begin to sprout after 2 to 3 months in storage. High storage temperatures will induce earlier sprouting. To avoid sprouting, you can apply a sprout inhibitor, such as chloroisopropyl-N phenylcarbamate (CIPC) or maleic hydrazide. They should not be used on seed potatoes. CIPC is applied as a gas after curing is completed. Maleic hydrazide is applied in the field during late full bloom to postbloom, and needs to be transported from the leaves to the tubers to be effective.

Storage

Before storage, potatoes should be culled and cured. Cull and discard any damaged, diseased or frozen tubers. Curing potatoes heals the skin, making it less susceptible to damage and disease. Cure potatoes by exposing them to temperatures between 50 and 60 degrees F and 95% relative humidity for 10 to 14 days.

Potatoes are either stored in refrigerated warehouses or nonrefrigerated bulk bins up to 20 feet deep. In the bulk bins, air should be forced from the floor through corrugated metal ducts up through the pile. This ensures good distribution of cool, humid air, which decreases shrinkage, sprouting, and decay. For table stock, ventilate at 0.6 to 0.7 cubic meters per minute per ton. For chipping stock, use 0.8 to 1 cubic meter per minute per ton. If airflow is too high, the relative humidity surrounding the potatoes may drop, causing weight loss. Air-cooled storage rooms may also be used, but you must ensure that night temperatures are low enough to keep your storage room cool and high enough to prevent freezing.

Hold table potatoes at 38 to 40 degrees F, decreasing field temperature 5 degrees per week to the desired storage temperature. Store processing potatoes at 50 to 55 degrees F, although Russet Burbank for processing can be stored at 45 degrees F. Cool processing potatoes to the final storage temperature at a rate of 3 to 4 degrees per week. Processing potatoes stored below 40 degrees F will build up sugars that will cause the flesh to turn brown or black when fried. Once the desired holding temperature is reached, keep the temperature differential about 2 degrees F between the top and bottom of the pile. Do not allow potatoes to remain at temperatures below 30 degrees F, or freezing injury will occur, leading to rot. For all types of potatoes, storage humidity should be 95%, but avoid moisture condensation on tubers and storage walls and ceilings. When diseases such as late blight and Pythium leak are severe, maintain lower humidity during storage and ensure good air circulation.

Packaging

When ready for market, potatoes can be packed into perforated plastic bags that will help retain moisture but provide for air circulation and proper cooling during transport. Potatoes can also be packed into cardboard boxes with ventilation holes.

Mechanical and Physiological Disorders

Besides sprouting, potato disorders include:

Disorder	Symptoms	Control
Greening	surface turns green with light treatment	minimize exposure to light
Black heart	sharply defined, purplish-grey to black area in center or cavities due to oxygen starvation	provide good air circulation to prevent heating and oxygen deprivation; avoid chilling injury
Chilling injury	gray to red-brown areas or black heart	store tubers above 37 degrees F
Freezing injury	vascular tissue turns black and tubers leak when thawed	store tubers above 37 degrees F
Blackspot	internal black spots due to bruising; can cause shatter in some potatoes	minimize bruising; warm to 60 degrees F before grading

Diseases

Postharvest diseases include the following:

Disease	Casual agent	Symptoms
Dry rot	Fusarium spp.	brown, firm, sunken flesh; sunken and wrinkled surfaces with blue or white protuberances
Soft rot	Erwinia carotovora	soft, water cavities in flesh, foul smell; in non-russeted varieties, shallow, round lesions around lenticels
Leak	Pythium	oozing tubers; well defined areas between healthy and diseased flesh; pink then black flesh with granular, mushy rot
Late blight	Phytophthora infestans	small, shrunken, dark spots in flesh; foul smell
Ring rot	Cornybacterium sepedonicum	vascular ring yellow

 

Potatoes Exports by Country

OCTOBER 21, 2017 BY DANIEL WORKMAN

French fries in global demand

Global sales from potatoes exports by country amounted to US$3.7 billion during 2016 for products in their raw form, while the value of shipments for prepared or preserved potatoes including frozen french fries represents an additional $8.5 billion.

Overall, the value of raw potatoes exports increased in value by an average 7.6% for all exporting countries since 2012 when raw potatoes shipments were valued at $3.5 billion. Total prepared or preserved potatoes shipments depreciated by 9.9% over the same 5-year period.

The 4-digit Harmonized Tariff System code prefix for raw potatoes while 0701 while the 6-digit prefix for frozen prepared or preserved potatoes including french fries is 200410. In addition, 200520 is the 6-digit prefix for unfrozen potatoes prepared or preserved with vinegar or acetic acid.

Potatoes Exports by Country: Raw

Below are the 15 countries that exported the highest dollar value worth of unprocessed raw potatoes during 2016:

Netherlands: US$669.9 million (18% of total raw potatoes exports)

France: $603.4 million (16.2%)

Germany: $349.2 million (9.4%)

Canada: $228.1 million (6.1%)

China: $227.2 million (6.1%)

Belgium: $210.2 million (5.7%)

United States: $203.6 million (5.5%)

Egypt: $162 million (4.4%)

United Kingdom: $150.9 million (4.1%)

Spain: $136.2 million (3.7%)

Israel: $90.4 million (2.4%)

Italy: $71.9 million (1.9%)

India: $60.3 million (1.6%)

Denmark: $58.3 million (1.6%)

Cyprus: $52.7 million (1.4%)

The above countries produced 88% of raw potatoes exports in 2016.

Among the above countries, the fastest-growing raw potatoes exporters since 2012 were: India (up 218.3%), China (up 71.8%), Canada (up 41.2%) and Spain (up 33.3%).

Four countries posted declines in their exported raw potatoes sales: Denmark (down -17.9%), United Kingdom (down -16%), Netherlands (down -5.3%) and the United States (down -0.6%).

Potatoes Exports by Country: Prepared or Preserved

Frozen prepared or preserved potatoes including french fries amounted to $6.4 billion in export sales for 2016, while international shipments of unfrozen prepared or preserved potatoes were worth $2.1 billion.

Below are the 15 countries that exported the highest dollar value worth of prepared or preserved potatoes during 2016:

Netherlands: US$2 billion (22.9% of total prepared or preserved potatoes exports)

Belgium: $1.8 billion (21.6%)

United States: $1.4 billion (16.3%)

Canada: $993.7 million (11.6%)

Germany: $422.4 million (5%)

France: $373.1 million (4.4%)

United Kingdom: $230.3 million (2.7%)

Poland: $219.1 million (2.6%)

Argentina: $189.5 million (2.2%)

Mexico: $82.7 million (1%)

Spain: $67.4 million (0.8%)

New Zealand: $62.6 million (0.7%)

Egypt: $59.1 million (0.7%)

Austria: $50.6 million (0.6%)

Malaysia: $45.6 million (0.5%)

The 15 countries listed immediately above shipped 93.6% of all prepared or preserved spuds in 2016.

Among the above countries, the fastest-growing prepared or preserved potatoes exporters since 2012 were: Spain (up 82.3%), Belgium (up 17.9%), Netherlands (up 17.2%) and Argentina (up 17.1%).

The five countries that posted declines in their exported prepared or preserved potatoes sales were: Malaysia (down -20.5%), Mexico (down -11.6%), New Zealand (down -11%), Germany (down -2.7%) and France (-2.1%).

One final note to crown the potato king of international trade: Dutch exporters placed first in the international trade of both raw and processed spuds. http://www.worldstopexports.com/potatoes-exports-by-country/

See also Highest Value Dutch Export Products, Asparagus Exports by Country, Top Sweet Pepper and Chili Pepper Exports and Top Cucumbers Exporting Countries

Click here to know more http://www.sciencedirect.com/science/book/9781845695972

 

Grades of Potatoes

U.S. No. 1 consists of potatoes which meet the following requirements:

1. Similar varietal characteristics, except when designated as a mixed or specialty pack;
2. Firm;
3. Fairly clean;
4. Fairly well shaped;
5. Free from:
6. Freezing;
7. Blackheart;
8. Late blight, southern bacterial wilt and ring rot; and,
9. Soft rot and wet breakdown.
10. Free from damage by any other cause. See §§51.1564 and 51.1565.
11. Size. Not less than 1-7/8 inches in diameter, unless otherwise specified in connection with the grade.
12. For tolerances see §51.1546.

U.S. Commercial consists of potatoes which meet the requirements of U.S. No. 1 grade except for the following:

1. Free from serious damage caused by:
2. Dirt or other foreign matter;
3. Russet scab; and,
4. Rhizoctonia.
5. Increased tolerances for defects specified in §51.1546.

U.S. No. 2 consists of potatoes which meet the following requirements:

1. Similar varietal characteristics, except when designated as a mixed or specialty pack;
2. Not seriously misshapen;
3. Free from:
4. Freezing;
5. Blackheart;
6. Late blight, southern bacterial wilt and ring rot; and,
7. Soft rot and wet breakdown.
8. Free from serious damage by any other cause. See §§51.1564 and 51.1565.
9. Size. Not less than 1-1/2 inches in diameter, unless otherwise specified in connection with the grade.
10. For tolerances see §51.1546.

https://www.ams.usda.gov/grades-standards/potatoes-grades-and-standards

 

Specifications

Restrictions on the sale of potatoes

No person shall sell potatoes in the Republic of South Africa

unless:

– Potatoes are sold according to the classes

– Potatoes comply with the standards regarding quality

– Containers in which such potatoes are presented for

sale have been manufactures according to the requirements

– Potatoes are packed in a container and in a prescribed

manner

– Containers carrying potatoes are marked with the particulars

and in the manner prescribed

3. Classes for potatoes

There are four classes for potatoes namely:

– Class 1

– Class 2

– Class 3

– Lowest class

4. Standard for classes

Potatoes which are classified as class 1, class 2, class 3

and the lowest class shall comply with the specifications as

per regulation.

The maximum extent to which class 1, class 2, and class 3

potatoes deviates from the prescribed specifications shall

be determined as follows:

• Examine the tubers in the sample of the consignment

physically and on the basis of the colour plates, in order

to determine whether such deficiencies occur thereon

or therein: provided that any tuber from the sample suspected

of internal deficiencies may be dissected for the

purpose of confirmation or otherwise of the observation

concerned.

• Determine with regard to each of the separate quality

factors.

• Express the mass determined as the percentage of the

net mass of the container of potatoes, such percentage

represents the extent to which potatoes with deviation

concerned are present in such container: provided that

in case of the internal quality defects the degree of the

deviation shall be determined as a percentage of 3kg.

5. Container requirements

Potatoes shall be packed in containers which:

– Are new, intact, clean, suitable and strong enough for

the packing and normal handling of potatoes.

– Shall not impart a taste or odour to the potatoes.

– In case of a carrier container, shall be strong enough

not to bulge out or dent in during normal handling and

transporting practices.

6. Packing requirements

– Potatoes shall, in the case of class 1 class 1, class 2,

class 3 and lowest class correspond in cultivar, class,

and size group in the same consignment: provided that

the size group shall not be applicable to class 3.

– Containers shall be closed by bunch tying with the suitable

wire tie or by sewing with suitable tying string or

with a suitable lid or whatever the choice of packaging

may be.

7. Marking requirements

– The prescribed marking requirements in the regulations

are used to provide the consumer with accurate

and relevant information on a product, so as to allow an

informed and personal choice to be made.

– Containers containing potatoes shall be marked in clear

and legible block letters of at least 5mm in height using

English and any other official language with the following

compulsory particulars:

8. Potato group size

Name or trade mark of the

producer, owner or packer

Name of the product

Physical address of the

producer, owner or packer

Pack date

Size

Net mass

Class

Country of origin

Cultivar

23.09.2014

Vanderplank

Class 1

Size group Mass

 

(i) Baby 5g (min) – 50g (max)

(ii) Small 50g (min) – 100g (max)

(iii) Medium 90g (min) – 170g (max)

(iv) Large-medium 150g (min) – 250g (max)

(v) Large 250g (min) – and more

9. Restricted particulars

No wording, illustration or other means of expression which

constitute a misrepresentation or which directly or by implication

may create a misleading impression of the content or

the quality or the class thereof, shall appear on a container

containing potatoes. http://www.potatoes.co.za/SiteResources/documents/General%20requirements%20for%20grading%20,%20packing%20and%20marking%20of%20potatoes.pdf

click here for more details https://www.alibaba.com/showroom/potato-specifications.html

processing potato equipments

Sormac is an international specialist in the development and production of potato processing equipment. Apart from stand alone potato processing equipment like a potato peeler, Sormac also produces complete lines and technology for food processing, as well as supplying reliable service worldwide through our skilled engineers. We aim to provide our customers with adequate help as effectively as possible.

Quality potato processing equipment

Sormac solutions for vegetable processing mainly consist of potato processing equipment like a potato peeling machine, carrot processing equipment, onion peeling equipment, leafy vegetable processing equipment, cucumber processing equipment and bell pepper de-coring equipment. Reliability, hygiene, precision and a long lifespan are typical of all Sormac equipment as a result of our market oriented development policy.

Reliable machines

Below, you’ll find a list of our potato processing machines. Please click on the links for more details and product folders.

– Potato processing equipment: Screw de-stoner SO 50/250-R, SO 50/250-C
– Potato peeler: Carborundum roller peeler CRP
– Potato processing equipment: Revolver peeler CRR-25/250

Potato peelers 

The MS-Combi potato knife peeler is suitable to peel pre-cleaned potatoes. Together with a screw de-stoner type SO, a roller inspection table type RLT and the AFW-40 weighing machine, this peeler creates a complete potato peeling line.  The potatoes will also notice the difference; there is a trend that growing numbers of small and medium sized peeling companies are switching to knife peeling and closing the door on the era of carborundum forever. Consumers appear to find more favour with knife peeled potatoes than with carborundum peeled ones. Knife peeled potatoes look far nicer. And an added advantage is the longer shelf life, which is of course fantastic news for the end users with Sormac potato peelers!

Over 100 sold machines are proof of the quality of Sormac’s drum knife peeler. However, that was no reason for the Sormac engineers to rest on their laurels. Without detracting from the basic concept, they drastically changed a number of details of the drum:

On two sides of the drum, the small cleaning panels were replaced with hinged panels across the length of the drum.

All plastic parts are made of blue material.

Only antibacterial plastic is used complying with the latest EU regulations.

The numerous users speak highly of the potato peelers due to its conveniently arranged and hygienic design and easy cleanability. The new measures will further improve this. Access is increased and the knives can be exchanged more easily.

The results of a poll among 25 users of our potato peelers with the question why they would choose a Sormac machine again, say more than we could say ourselves:

Lower energy consumption

Only 3 motors for the whole machine

Low noise levels

Long knife life

Constant speed of the knives in comparison with wing-knives

All elements that make the Sormac potato peelers unbeatable!

https://www.sormac.eu/en/potato-processing-equipment/

 

The potato’s biological characteristics

Many constraints derive from the biological characteristics of the potato itself. These include the low multiplication rates of seed tubers, and the technical difficulties and costs associated with maintaining seed quality through successive multiplications, owing to the potato’s susceptibility to soil and seed-borne insect pests and diseases. Seed tubers are also bulky: two to three tonnes per hectare is the typical seed requirement. Stringent phytosanitary restrictions limit the movement of potato germplasm, seed tubers and fresh ware potatoes. Potatoes have high fertilizer requirements but low utilization efficiency. Post-harvest, fresh potato tubers deteriorate quickly in tropical and subtropical environments, especially in the lowlands. Lack of efficient seed systems Many developing countries lack efficient systems for the regular multiplication and distribution of certified seed tubers and the rapid deployment of new, improved varieties. Causal factors include the limited technical capacity of human resources, lack of managerial expertise and inadequate resource allocations to seed systems and the potato subsector in general. As a result, farmer-based seed systems are still common, and have managed to supply planting material of limited quality over the years, and contributed to expanding cultivation of the crop. Farmer seed systems face many challenges, but also offer an opportunity toimprove seed supply, provided suitable training is available and links with the formal sector are established. Diseases and insect pests Diseases and insect pests are another major constraint. New strains of late blight have reached many developing countries and continue to spread. Late blight constitutes the most serious threat to increased potato production. Second to late blight in importance, particularly in warmer, more tropical regions, is bacterial wilt. The impact of insect pests varies between regions. Major insect pests include aphids, tuber moths, leaf miners, Colorado potato beetle and Andean potato weevil.

Social economic factors

High production costs and lack of credit Compared to other food crops, production of potatoes is capital-intensive, requiring the purchase of large quantities of bulky seed and the application of high-cost inputs such as fertilizers and pesticides. With limited access to credit and few means of mitigating the risks of taking out loans, small-scale farmers find it difficult to compete in potato production. The current global financial crisis could leave a great number of farmers with little money and no credit to invest in production. Price instability With potato becoming increasingly a cash crop, small-scale potato growers are vulnerable to abrupt changes in input and output prices. Seasonal and year-to-year price movements can affect individual small growers who lack the financial resources and resilience of larger producers and cooperatives. Inefficiency of local markets Potato prices are usually determined by supply and demand, not the vagaries of international markets as in the case of cereals. It is, therefore, a crop that can help low-income farmers and consumers to ride out episodes of food price inflation, such as that experienced worldwide in 2007-08. However, the profitability of potato depends on efficient local markets and measures to control overproductionLimited access to higher value markets To be successful, small-scale potato growers need access to profitable emerging domestic markets – such as the rapidly growing processing segment – as well as to potato export markets. However, access to domestic markets is often restricted by the marketing power of foreign suppliers, while exports are constrained by trade barriers in developed countries to processed products from the developing world. However, there are encouraging “success stories” that illustrate how small-scale producers can increase production and expand their market share. In India, potato growers who adapted new technology with the support of McCain Foods Ltd more than doubled their yields and incomes. Other private industries, including small businesses, have launched potato chips made from coloured native potatoes that were prototyped by CIP in order to promote the sustainable use of biodiversity in the Andean Region. Recent legislation in the USA and Europe provide greater access to agricultural products from the developing world

Policy and institutional factors

Neglect of the potato subsector With a few notable exceptions – such as Ethiopia – most developing countries have policies toward the potato subsector, and especially small-scale producers, that can be best characterized as “benign neglect”. Little or no public investment is targeted at integrated strategies for crop improvement, value addition and marketing schemes or the potato production-processing-marketing chain. Many countries lack adequate seed production systems backed by certification and seed laws. Breeding rights are often not respected, reducing incentives to breeders to create new adapted and resistant varieties. In many areas, poor infrastructural facilities and poor access to markets are also major challenges to expansion of potato production and its profitability. Inadequate capacity building initiatives The potato has attracted private sector investment in the crucial area of seed multiplication and seed systems in only a few countries. Support for programmes for the diffusion of new varieties and for the scaling up of existing integrated disease and insect pest management technologies and methodologies is generally inadequate. Programmes to upgrade the skills of potato growers need to be matched by government efforts to create, monitor and enforce regulations on pesticide use and the spread of pesticide or fertilizer residues into water supplies, which are major constraints to the sustainability of potato production systems.

Lack of support to farmer organizations and entrepreneurs Support for potato farmer groups and associations and for local entrepreneurship is lacking in many countries. In Bangladesh and Pakistan, powerful lobbies represent the most serious obstacle to the development of a local seed potato industry. One notable exception is Argentina, where efforts are being made by public and private sector to improve seed quality and promote variety development, and to transfer technology for integrated crop management to its contract growers.

Good agricultural practices

G APs may be applied to a wide range of farming systems and at different scales. They are applied through sustainable agricultural methods, such as integrated pest management, integrated water and fertilizer management, and conservation agriculture. GAPs are based on four principles: 1. to economically and efficiently produce sufficient quantities of safe and nutritious food; 2. to sustain and enhance ; 3. to maintain viable farming enterprises and contribute to livelihoods; 4. to meet the cultural and social needs of society. GAP applications are being developed by governments, NGOs and the private sector to meet the needs of growers and processors and for other specific purposes. They provide the opportunity to assess and decide on which to follow at each step of the production process. It is important that GAPs are applied in a coordinated way. For each agricultural production system, GAPs should be part of a comprehensive management strategy, providing for adjustments when needed in response to changing conditions. The implementation of such a management strategy requires knowledge, planning, measuring, monitoring and record-keeping at each step of the production process. Adoption of GAPs may sometimes result in higher production, processing and marketing costs, and higher prices for the consumer. To minimize costs, while maintaining the quality and safety of food products, participatory technical training and advice can be used to inform farmers of new technologies that will benefit them. Information on options for GAP adoption would be facilitated through the use of common databases and information exchange platforms on available enabling technologies and integrated production techniques for different major agroecological areas.

Examples of GAPs

Soil management 6 Reduce wind and water erosion through hedging and ditching. 6 Apply fertilizers at appropriate moments in adequate doses (e.g. based on soil analysis and crop requirement) to avoid extra costs and possible run-off and leaching. 6 Maintain or restore soil organic content through application of manure, use of grazing and/or crop rotation . 6 Reduce soil compaction by avoiding use of heavy machinery. 6 Maintain soil structure by limiting heavy and sometimes unnecessary tillage practices, and through use of cover crops such as pulses.

Water use efficiency 6 Use minimum or zero-tillage and maintain soil cover to reduce soil evaporation and improve soil structure and water infiltration. 6 To avoid water loss by drainage, schedule irrigation and monitor plant needs and soil water reserve status. 6 Prevent soil salinization by matching water input to needs, allowing some drainage and recycling water whenever possible. 6 Avoid excessive drainage and fertilizer run-off. 6 Maintain permanent soil cover in winter to avoid nitrogen run-off and wind erosion that contributes to soil degradation. 6 Carefully manage the water table by limiting withdrawals. 6 Avoid soil compaction (e.g., caused by too many passes of farm machinery) which can cause water logging and lead to emergence of potato diseases during storage.

ftp://ftp.fao.org/docrep/fao/012/i1127e/i1127e01.pdf