Potatoes
2. Size

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2.1 Requirements

The Canada No. 1 grade provides for various minimum and maximum size designations, but in all other respects meet the requirements of Canada No. 1. All Canadian grades require that potatoes be sized. Potatoes may meet either the minimum and maximum diameter size or weight requirements. The specific tolerance for each grade is as follows:

Canada No. 1

A) Round type potatoes

  1. Have a minimum diameter of 57 mm (2 ¼ inches) and a maximum diameter of 89 mm (3 ½ inches), or have a minimum weight of 142 g (5 ounces) and a maximum weight of 340 g (12 ounces);
  2. In the case of new potatoes (round type), may have a minimum diameter of 48 mm (1 ⅞ inches), where the new potatoes are shipped before October 1 *(TM) in the year in which they were grown.
  3. In the case of round type potatoes commonly referred to as "Small", may have a minimum diameter of 38 mm (1 ½ inches) and a maximum diameter of 57 mm (2 ¼ inches). *(TM)

B) Long type potatoes

  1. Have a minimum diameter of 51 mm (2 inches) and a maximum diameter of 89 mm (3 ½ inches), or a minimum weight of 113 g (4 ounces) and a maximum weight of 340 g (12 ounces); except that potatoes 89 mm (3 ½ inches) or more in length may have a minimum diameter of 44 mm (1 ¾ inches) and, in either case, at least 60% by weight of the potatoes in the lot shall have a diameter of at least 57 mm (2 ¼ inches) or a weight of at least 142 g (5 ounces);
  2. In addition to meeting the requirements for long type potatoes, new potatoes (long type), may have a minimum diameter of 48 mm (1 ⅞ inch) rather than 51 mm (2 inches), where the new potatoes are shipped before July 1 in the year in which they were grown.
  3. Long type potatoes shipped on the interprovincial market only, all year round, may have a minimum diameter of 48 mm (1 ⅞ inches) and a maximum diameter of 76 mm (3 inches), or a maximum weight of 283 g (10 ounces), and at least 75% by weight of the potatoes in the lot shall have a diameter of at least 51 mm (2 inches) or a weight of at least 113 g (4 ounces). This applies only where the packages are labelled with the Grade/Size designation "Canada No. 1 1 ⅞" to 3"".
  4. In the case of long potatoes commonly referred to as "Small", may have a minimum diameter of 38 mm (1 ½ inches) and a maximum diameter of 51 mm (2 inches). *(TM)

C) Potatoes of any type

Canada No. 1, 19 mm to 41 mm (¾ to 1 ⅝ inches), commonly referred to as "Creamer"
  1. A minimum diameter of 19 mm (¾ inch) and a maximum diameter of 41 mm (1 ⅝ inches); *(TM)
Canada No. 1 "Chef" 70 mm to 114 mm (2 ¾ to 4 ½ inches)
  1. A minimum diameter of 70 mm (2 ¾ inches) and a maximum diameter of 114 mm (4 ½ inches); or
  2. A minimum weight of 227 g (8 ounces) and a maximum weight of 794 g (28 ounces).
Canada No. 1 "Large" 76 mm to 114 mm (3 to 4 ½ inches)
  1. A minimum diameter of 76 mm (3 inches) and a maximum diameter of 114 mm (4 ½ inches); or
  2. A minimum weight of 283 g (10 ounces) and a maximum weight of 794 g (28 ounces).

Canada No. 2

Potatoes of any type

  1. Potatoes shipped all year round have a size of 44 mm (1 ¾ inches) to 114 mm (4 ½ inches) in diameter or a maximum weight of 794 g (28 ounces), provided that 75% by weight of the specimens in the lot have a diameter of at least 51 mm (2 inches) or a weight of at least 113 g (4 ounces).

2.2 Measuring Size

The measurement for minimum and maximum diameter shall be the greatest distance of a potato taken at right angles to the longitudinal axis, disregarding the position of the stem.

To determine off-size specimens, inspectors shall use a metal ring sizer. Suspected specimens are placed on the ring. When checking for oversize, if the potato supports its own weight without falling through the ring, it will be scored for oversize when checking the upper size range. However, when checking for undersize, if the potato passes through the ring even if it touches the sides, it will be scored for undersize when checking the lower size range.

Note: The percentage of undersize or oversize specimens should not be noted on the certificate if the lot meets the size requirements for the grade unless the applicant specifically requests this information. In cases where the lot fails the size requirements, the exact percentage should be shown under the "Grade Defects" heading.

2.3 Special Lot Tolerance for Size

Certification of Canada No. 1 long type potato of a size 51 mm to 89 mm (2 to 3 ½ inches) has a special lot tolerance requiring 60% to be 57 mm (2 ¼ inches) or greater. Likewise, certification of Canada No. 1 long type (interprovincial) 48 mm to 76 mm (1 ⅞ to 3 inches) and Canada No. 2 potatoes include special lot tolerance for size requiring 75% to be 51 mm (2 inches) or greater. It should be noted that U.S. No. 1 and U.S. No. 1 Size A also have special lot tolerances for size.

The procedure for inspecting to the special lot tolerances will be explained below using the 60% tolerance as an example.

Sampling for lot compliance with the lot tolerance (60% or 75%) for size is based on a reduced sample size unless there is an indication of non-compliance.

When verifying the 60%, 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger size requirements on long varieties of potatoes, inspectors should initially determine the percentage of potatoes 57 mm (2 ¼ inches) and larger or 142 g (5 ounces) and larger in the first four samples inspected in the lot.

The weight and the calculated percentage of potatoes 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger should be shown on the detail sheet. (See Figure 1.)

The same samples should also be checked at this time for defects, undersize and oversize.

If, in the first four samples the average number of specimens 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger in size is 65% or less, or if any bag is below 60%, then four additional samples should be examined for the special lot tolerance. (See Figure 2.) Using an additional 5% as a cut-off provides an "insulation factor" when sampling the first four samples.

If the average still does not exceed 65%, 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger, then all remaining packages in the sample should be measured to determine compliance with the special lot tolerance for size. (See Figure 3.)

Note: There is a possibility that the load may fail for undersize, but meet the special lot tolerance. However, the Regulations require that both be met for the load to pass.

On the face of the certificate under the "Size" heading, the inspector should show the size range and the compliance to the 60% requirement. If all samples have been examined for meeting the size requirement and the actual percentage found is greater than or equal to 60%, (i.e., 65%, 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger), inspectors are advised to only report on the certificate, that the 60%, 57 mm (2 ¼ inches) or 142 g (5 ounces) and larger requirement has been met and leave the detail to show the actual size and percentage.

Potatoes packed by count

Where potatoes are packed and labelled with a count designation, they shall meet the minimum and maximum size designations according to variety and grade. However, not more than 10% of the cartons shall contain up to 5% fewer or more potatoes than the count designation shown on the label.

When undersize or oversize specimens are also defective

Undersize and oversize specimens which are also defective should be scored twice. First as off-size, second as a defect. This is necessary because the grades have separate tolerances for off-size and defects.

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Inspection Details. Description follows.

Description for form – Inspection Details

This form consists of: Inspection, Date, Time, Verbal Notification of Findings, Certifiate Number, Car or Truck Number, Name of the Packer or Grower, The Product or Variety Declared, Package or Weight, Inspection Number, Decay, Mechanical Damage, Sunburn, Undersize, Total Defects, Grade, Size.

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