QUALITY of Early and Ware Potatoes

PROVISIONS CONCERNING QUALITY

  • The purpose of the standard is to define the quality requirements of early and ware potatoes at the export-control stage after preparation and packaging.
  • However, if applied at stages following export, products may show in relation to the requirements of the standard:
    • a slight lack of freshness and turgidity
    •  a slight deterioration due to their development and their tendency to perish.
      • The holder/seller of products may not display such products or offer them for sale, or deliver or market them in any manner other than in conformity with this standard. The holder shall be responsible for observing such conformity.

Minimum requirements

  •  Subject to the tolerances allowed the tubers must be:
  • Of normal appearance for the variety, according to the producing area;
    • The normal appearance of a variety may vary a little, e.g. by the shape and the appearance of the tubers. This variation is due to the type of soil, the cultivation techniques and the climatic conditions or in general depending from the producing area and crop year.
  • Intact, i.e. they should not have had any part removed nor have suffered any damage making them incomplete;
    • Early and ware potatoes must not have any damage or injury spoiling the integrity of the produce. 
    • The tubers may be damaged by mechanical causes or animal bites. Tubers are regarded as intact provided removing the affected part does not constitute more than 10 % of the weight of the tuber:
      • The weight of the unpeeled tuber is determined.
      •  The damage has to be removed by a single cut as close as possible to the damage.
      •  The weight of the defective part is determined.
      •  The percentage of the removed part is calculated on the basis of the weight of the whole tuber.
      • Superficial damage that can be removed by normal peeling is not regarded as a defect.
    • Sound; produce affected by rotting or deterioration such as to make it unfit for consumption is excluded;
    • Early and ware potatoes must be free from disease or serious deterioration which appreciably affect their appearance, edibility or keeping quality. In particular, tubers affected by rotting, even if the signs are very slight but liable to make the early and ware potatoes unfit for consumption upon arrival at their destination, are to be excluded.
    • Tubers showing the following defects are therefore excluded:
      • Wet rot.
      • Dry rot.
      •  Late blight (Phytophthora infestans) 
      •  Alternaria rot (Alternaria spp)
      • Brown rot (Pseudomonas solanacearum)
      • Gangrene (Phoma spp)
  • Practically clean;
    • Early and ware potatoes must be practically free of visible soil, dust, residue or other foreign matter. Brushing or washing of tubers is optional, but they should be free from attached earth. 
  • Firm;
    • Tubers must have retained their turgescence, with the skin tight and flesh resistant to slight thumb pressure. It is advisable not to keep tubers in an atmosphere which has a desiccating effect because, in such conditions, they will probably become soft and wrinkled.
  • Free of external or internal defects detrimental to the general appearanceof the produce, the quality, the keeping quality and presentation in the package, such as:
    • Brown stains due to heat; 
    • Cracks (including growth cracks), cuts, bites, bruise or roughness (only for varieties of which the skin is not normally rough) exceeding 4 mm in depth; 
  • Green coloration; pale green flush not exceeding one eighth of the surface area and which can be removed by normal peeling does not constitute a defect;
  • Green coloration on red skin varieties shows as a dark violet discolouration.
  •  Serious deformities;
    • Deformities such as knobbiness and other irregular shaped tubers as well as tubers with shapes making peeling difficult are not allowed.
  •  Grey, blue or black sub-epidermal stains; exceeding 5 mm in depth in the case of ware potatoes;
    • Grey, blue or black sub-epidermal stains are caused by more or less severe impacts during grading, sizing and packaging or from pressure during storage. Tubers are very susceptible when cold during handling. Therefore, it is recommended to warm up the tubers to about 15 °C before grading out of store. The best method to check for grey, blue or black sub-epidermal stains is peeling the tuber at the rose and the heel end. 
  •  Rust stains, hollow or black hearts and other internal defects;
  • In addition to the defects mentioned above, the following defects are excluded:
    • Glassiness is a physiological disorder. When external symptoms occur, the stem end is soft and the skin is wrinkled. The affected flesh varies from colourless or glassy translucent to straw colour or various shades of brown or black. The tissue is fragile and easily broken apart, watery and of jellylike texture. A sharp line of demarcation forms between the affected and healthy tissue. 
    • Corky ringspot or spraing disease (Tobacco rattle virus). 
  •  Deep common potato scab and powdery potato scab of a depth of 2 mm or more in the case of ware potatoes; 
  •  Superficial common potato scab, i.e. scab spots in all must not extend over more than a quarter of the surface of the tuber; 
  •  Frost damage and freezing injuries; 
  • Free of abnormal external moisture; i.e. adequately “dried” if they have
    been washed;
  • This provision applies to excessive moisture, for example, free water lying inside
    • the package, but does not include condensation on produce following release from cool storage or refrigerated vehicle.
  •  Free of any foreign smell and/or taste.
    • This provision applies to early and ware potatoes stored or transported under poor conditions, which have consequently resulted in their absorbing abnormal smells and/or tastes, in particular through the proximity of other product which give off volatile odours
  • In the case of early potatoes a partial absence of the skin shall not be considered as a defect. Ware potatoes must be covered with well-formed skin, i.e. the skin has to be fully developed and mature and cover the whole surface of the tuber.
  • As early potatoes are harvested before they are completely mature, their skin must not adhere closely to the flesh and may at least partly peel off naturally.
  • In early potatoes, no sprouting is allowed. Ware potatoes must be practically unsprouted, i.e. sprouts may be no longer than 3 mm.
  • The re-growth of the eyes being mainly located at the rose end of the tubers accelerates the loss of moisture, which leaves the tubers soft and makes the tubers more susceptible for internal bruising. Therefore, any sprouting is lowering the quality.
  • The development and condition of the early and ware potatoes must be such as to enable them:
    • To withstand transportation and handling
    • To arrive in satisfactory condition at the place of destination.
  • Each package or lot must be free from waste, i.e. attached or loose earth, detached growth shoots, extraneous matter.