Plums and Prunes

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  1. General Requirements
    • 1.1 Grades
    • 1.2 Type
    • 1.3 Properly Packed
  2. Shape (Well-Formed)
  3. Maturity and Firmness
  4. Colour
    • 4.1 Plums
    • 4.2 Italian Type Prunes
  5. Cleanliness
  6. Size
    • 6.1 Measuring Size
    • 6.2 Varietal Minimum Size Requirements
    • 6.3 General Size Requirement
  7. Permanent Defects
    • 7.1 Drought Spots
    • 7.2 Growth Cracks
    • 7.3 Hail Injury
    • 7.4 Insect Stings/Injury
    • 7.5 Limb Rub and Leaf Marks
    • 7.6 Russeting
    • 7.7 Scale
    • 7.8 Scars
    • 7.9 Split Pits
    • 7.10 Sunscald
    • 7.11 Sunburn
  8. Condition Defects
    • 8.1 Bruising
    • 8.2 Decay
    • 8.3 Discolouration
    • 8.4 Shrivelling
    • 8.5 Skin Breaks/Tears
  9. Tolerances
    • 9.1 Tolerances prescribed in the regulations
    • 9.2 Examples for applying tolerances

Appendix I - Tolerances for Canada No. 1 and Domestic Grades

1. General Requirements

1.1 Grades

The grades for plums and prune plums are Canada No. 1 and Canada Domestic. The tolerances established in the Regulations do not distinguish between plums and prune plums.

Note: Canada Domestic is not permitted for use within Ontario.

1.2 Type

The Canadian grades and standards for Plums and Prunes make mention of Peach Plums. These are hybrid varieties such as crosses between peaches and plums. The standards however do not apply to any "interspecific" plums, i.e., hybrids of two or more fruit species.

1.2.1 Plums

Plums come in many varieties which have different flavours, shapes and colours.

1.2.2 Italian Type Prunes

Prunes, generally speaking, are plums that are suitable for drying because of their high sugar content which prevents them from moulding around the pit. Distinguishing characteristics of the prune group are freestone fruits (flesh freely separates from the pit) which are usually oval, sutured, bluish black or purplish black, having firm, greenish yellow to golden flesh. They are classified as "Italian Type Prunes".

1.2.3 Identifying Type

Although inspectors are not required to certify specific varieties, inspectors may note the variety if it is clearly stated on the packages or may include the statement "Advised by applicant that the variety is". Inspectors should, however, distinguish between "Italian Type Prune Plums and Plums".

1.3 Properly Packed

The regulations require that plums be "properly packed". Product meeting this requirement as defined below may be reported as such:

Properly Packed: means that when the plums are packed in a package, they are not so packed as to be slack, over-pressed or otherwise in a condition likely to result in damage during handling or while in transit.

Slack Filled: means the package is clearly not full and a free movement of the product is possible or evident.

Over-pressed or Very Tight: means that the package is excessively filled, resulting in damage to the product within.

Slack filled or Over-pressed or very tight: means that the product is not in compliance with the "properly packed" requirement.

2. Shape (Well-Formed)

Regulations for both grades require that plums and prunes be well formed.

Well-formed: means that they have a shape characteristic of the variety (when mature), that they are free from deformities caused by early injury, free from lopsided specimens as a result of drought spot injury, and free from specimens that are doubles. Fruits that show distinct split pits should be scored as split pits and not as misshapen.

3. Maturity and Firmness

Maturity: Regulations for both grades require that plums and prunes be mature. "Mature" means that they are well developed and have reached a stage of maturity that will ensure a proper completion of the ripening process. In the case of green fleshed varieties, the flesh has started to break from a green to a light green and in the case of yellow fleshed varieties, the flesh has started to break to a yellow or amber colour. Also, the flesh should have some sweetness to the taste when chewed. In the case of red fleshed plums, the flesh must show a definite break to red.

Firmness: Plums and prunes should be described in the following stages: Hard, Firm, Firm Ripe, Ripe and Soft. In judging the firmness of Italian Type Prunes, inspectors should bear in mind that prunes yield readily to pressure.

The following are guidelines when reporting on firmness:

Hard: Fruits do not yield to ordinary pressure but usually will show slight springiness.

Firm: The flesh yields slightly to moderate pressure, especially around the blossom end.

Firm ripe: The flesh yields readily to moderate pressure.

Ripe: The flesh yields readily to slight pressure. (The fruit is sweet and juicy and ready for immediate consumption.)

Soft: This is the final stage of maturity before complete deterioration. Fruit that shows mushiness or breakdown of the flesh (not bruising) caused by advanced maturity have no commercial value, and should be reported as soft and scored against all grades.

4. Colour

4.1 Plums

Canada No. 1

Canada No. 1 requires plums to be of good colour which means that:

  • the plums are of the colour characteristic of the variety when mature.

Canada Domestic

Canada Domestic requires plums to be of fair colour which means that:

  • not less than 75% of the plums are of the colour characteristic of the variety when mature.

4.2 Italian Type Prunes

Canada No. 1

Requires prunes to be of good colour which means that:

  • not less than 75% of the surface area of the prune is of the colour characteristic of the variety when mature;

Canada Domestic

Requires prunes to be of fair colour which means that:

  • not less than 50% of the surface area of the prune is of the colour characteristic of the variety when mature;

5. Cleanliness

Cleanliness is seldom a factor in the inspection of plums and special care should be exercised in scoring this defect.

Canada No. 1

  • Canada No. 1 plums are required to be fairly clean.
  • "Fairly clean" means that the individual specimen is free from dirt, dust, spray residue or other foreign material that is noticeably in contrast with the colour of the plum.

Canada Domestic

  • Canada Domestic plums are required to be reasonably clean.
  • "Reasonably clean" means that the individual specimen is free from dirt, dust, spray residue or other foreign material that is seriously in contrast with the colour of the plum.

6. Size

6.1 Measuring Size

Plums and prunes must be measured on the diameter. Diameter means the greatest dimension of the fruit measured at a right angle to a line from the stem to the blossom end.

6.2 Varietal Minimum Size Requirements:

Variety Minimum Diameter
Burbank, Ozark, Premier, Vanier 41 mm (1 ⅝ inches)
Shiro 38 mm (1 ½ inches)
Methley, President, Washington 35 mm (1 ⅜ inches)
Bradshaw, Early Golden, all varieties commonly known as Early Blues 32 mm (1 ¼ inches)
Reine Claude, Stanley, Italian type prunes 29 mm (1 ⅛ inches)
Green Gage, Lombard, German prunes 25 mm (1 inch)
Shropshire Damson 19 mm (¾ inch)
All other varieties Characteristic of the variety when mature

6.3 General Size Requirement

For varieties not specified above, the size should be characteristic of the variety when mature.

Note: If a size greater than those specified above is marked on a package, they must meet the size marked.

In either grade, up to 5% by count of the plums or prunes in the lot may have less than the minimum diameter required.

7. Permanent Defects

7.1 Drought Spots

Drought spots are characterized by irregular or circular, slightly depressed areas on the skin which later turn brown or purplish in colour. As it progresses, the flesh beneath the affected areas will also turn brown and become very firm because of dead corky tissue. Cutting may be necessary to detect the defect.

Drought spots are scored as damage when:

Canada No. 1

Any drought spots are found on the fruit.

Canada Domestic

Drought spots affect more than 10% of the surface area.

7.2 Growth Cracks

Growth cracks are scored as damage when:

Canada No. 1

Any growth cracks are found on the fruit (except peach plum varieties).

Note: Peach plum varieties can have a crack at the calyx end provided the flesh is not exposed or the length of the crack does not exceed ¼ inch.

Canada Domestic
  • Cracks exceed one per plum.
  • Cracks exceed ¼ inch in length.
  • Cracks are not well healed.

7.3 Hail Injury

Hail injury that is sunken or discoloured are scored as damage when:

Canada No. 1
  • Any hail injury is found on the fruit.
Canada Domestic
  • It is not well healed.
  • It has broken the skin and exceeds ⅛ inch in diameter.
  • It has broken the skin and exceeds 3 marks per specimen.
  • It affects an aggregate area exceeding 2 inches in diameter.

7.4 Insect Stings/Injury

Insect injury will be scored as damage when:

Canada No. 1
  • Any insect injury is found on the fruit.
Canada Domestic
  • It exceeds 3 per specimen.
  • It extends into the flesh.
  • It aggregates more than ¼ inch per specimen.

7.5 Limb Rub and Leaf Marks

Limb rub and leaf marks will be scored as damage when:

Canada No. 1
  • Any injury is found on the fruit.
Canada Domestic
  • It affects more than 15% of the surface area.

7.6 Russeting

Russeting can be differentiated from scarring by the absence of any visible sign of injury to the fruit which would have caused a scar to form during the healing process.

Fruit with russeting will be scored as damage when:

Canada No. 1
  • Rough russeting aggregates more than ¼ inch on fruit 2 inches in diameter or smaller, and 2 inches on fruit greater than 2 inches in diameter, and
  • Smooth russeting exceeds 10% of the surface area.
Canada Domestic
  • Rough russeting aggregates more than ¾ inch on fruit 2 inches in diameter or smaller and 1 inch on fruit greater than 2 inches in diameter, and
  • Smooth russeting exceeds 25% of the surface area.

7.7 Scale

The most common type of scale insect found on plums and prunes is San Jose Scale. This scale is characterized by a circular shape which has a small nipple in a hollow at its centre. The fruit will have a spotted or mottled appearance and will usually have a reddish area around each scale.

Scale or scale marks will be scored as damage when:

Canada No. 1
  • They exceed 2 spots which contrast sharply with the background colour or they aggregate an area more than ¼ inch in diameter.
Canada Domestic
  • They exceed 5 spots which contrast sharply with the background colour or they aggregate an area more than ⅜ inch in diameter.

7.8 Scars

Scars can be differentiated from russeting by the presence of some type of injury or injuries (Example: cuts, scrapes, punctures, skin tears, etc.) which, in order to heal itself, has caused the fruit to scar over the injured area.

Scars may be of varying depth, colour and texture and may be caused by various factors.

Gum scars are characterized by their crescent shape. They resemble curculio injury except that there is no egg laying puncture beside them. These scars will sometimes exude clear gum.

Scars will be scored when:

Canada No. 1

Any scars are found on the fruit.

Canada Domestic
  • Scars aggregate over ¼ inch on a fruit 2 inches diameter or smaller, or over ⅜ inch on a fruit over 2  inches diameter, or
  • Exceed one per plum.

7.9 Split Pits

Split pits are only scoreable when they have caused the flesh to crack, generally at the stem end, or have caused the fruit to be misshapen.

Split pits will be scored when:

Canada No. 1
  • they cause any crack in the flesh that is unhealed,
  • the cracks in the flesh are healed and aggregate more than ¼ inch in length, or
  • they cause the shape of the fruit to be not well formed.
Canada Domestic
  • they cause any crack in the flesh that is unhealed,
  • the cracks in the flesh are healed and aggregate more than ¾ inch in length, or
  • they cause the shape of the fruit to be not well formed

7.10 Sunscald

This disorder is one of the most severe types of heat injury. It is characterized by a discolouration of the skin and flesh, and the flesh is soft and collapsed under the skin in the affected area.

Sunscald will be scored as damage when:

Canada No. 1

Any amount of sunscald is found on the fruit.

Canada Domestic
  • It does not blend with the normal background colour.
  • It has caused blistering or cracking of the skin.

7.11 Sunburn

Sunburn is a common defect in Italian type prunes. It usually occurs as reddish discolouration of the skin. Advanced states of sunburn may appear as flattening of the fruit or the skin may blister or crack. The flesh beneath the affected area may show some brownish discolouration.

Sunburn will be scored as damage when:

Canada No. 1

Normal colour of the skin has been materially changed or the skin is blistered, cracked or noticeably flattened.

Canada Domestic

The skin is seriously blistered, cracked or noticeably flattened or when it causes dark discolouration of the flesh.

8. Condition Defects

8.1 Bruising

Bruising may be caused by careless or rough handling or improper packing. Bruises are sometimes mistaken for decay. To distinguish between the two, it is only necessary to remember that in bruising the flesh has a mottled brown and white appearance and the skin is not browned; but in decayed spots, both the skin and flesh are brown.

Bruising will be scored as damage when:

Canada No. 1

Any bruise has caused the underlying flesh to discolour.

Note: Slight flattening of the skin with no flesh discolouration is incidental to good commercial handling and packing and should not be scored.

Canada Domestic

Bruises are soft and show discoloured flesh and affect more than 15% of the surface area.

8.2 Decay

The term "decay" is used to describe a deterioration involving decomposition, which is induced by fungi or bacteria and which is of a complete and progressive nature. Inspectors are not pathologists, so it is not their duty to name the specific decay affecting the fruit. Any soft decay or breakdown is scoreable against both grades.

8.3 Discolouration

8.3.1 Brown Surface Discolouration

This discolouration is generally as a result of rolling or scuffing during transit and is more noticeable on yellow type plums than on the darker skinned varieties. If these areas are sunken and or discoloured to the extent that they detract from the appearance, they should be scored when they exceed ½ inch in the aggregate area in both grades.

8.3.2 Internal Discolouration

The flesh of plums and Italian type prunes are subject to a brown discolouration which is more of a problem in some seasons than in others. Fruit showing areas of flesh that are translucent or have a yellowish to golden brown tinge, and the flesh is not soft or off-flavour, should not be scored against any grade. However, percentages may be reported at the specific request of an applicant, followed by the words "not affecting grade".

Internal discolouration should be scored as damage when:
Canada No. 1

Any amount of distinctly brown internal discolouration is found on the fruit.

Canada Domestic

When a midsection crosswise cut shows an area of flesh over ¼ inch in diameter that is distinctly brown or darker in colour, or when lighter shades or discolouration of the flesh are accompanied by a mushy condition or a distinct off-flavour or odour.

In doubtful cases, it may be necessary to make a supplementary lengthwise cut to be sure that the internal discolouration in other portions of the flesh is equivalent to more than an area ¼ inch in diameter at the crosswise midsection cut.

8.4 Shrivelling

Shrivelling sometimes occurs around the stem end of plums and prunes in the more advanced stage of ripeness. Shrivelling is sometimes found on more firm fruit. If this shrivelling occurs on the side of the fruit, it may be the result of drought.

Sometimes shrivelling is found on prunes that are low in sugar content, are tough and have stems firmly attached. This is the result of a physiological condition of the tree and such injury progresses after harvesting. Shrivelling may also be the result of excessive transpiration, in which case it is often accompanied by internal discolouration.

Slight wrinkling around the stem basin should be ignored providing the texture and taste of the flesh indicates that the plum or prune is mature. More severe wrinkling extending over the stem basin that materially affects the appearance of the fruit should be scored as "shrivelling" in both grades. If it is accompanied by a definite softness of the flesh, the specimen should then be scored as "soft".

8.5 Skin Breaks/Tears

Skin breaks or tears that are healed are scored as scars. For both Canada No. 1 and Canada Domestic, score any skin break ou tear, except those caused by pulled stems where the skin is torn within the stem cavity.

9. Tolerances

Tolerances are applied by count. Condition defects apply against the grade only at the time of shipping or repacking.

9.1 Tolerances prescribed in the regulations Shipping Point (condition defects apply against the grade)

  • Decay 3%
  • Same defect (other than decay) 5%
  • Total allowable defects in the lot 10%
  • Below size 5%

Destination (condition defects do not apply against the grade)

  • Same permanent defect 5%
  • Total allowable defects 10%
  • Below size 5%

9.2 Examples for applying tolerances

Example 1: At destination, inspection results show 1% decay, 2% growth cracks and 7% bruising. The lot meets grade because the 10% total defects tolerance has not been exceeded and the permanent defect does not exceed 5%.

Example 2: At destination, inspection results show no decay in evidence and 10% bruising. The lot meets grade because the 10% total defects tolerance has not been exceeded.

Example 3: At destination, inspection results show 1% decay, 7% growth cracks and 2% bruising. The lot fails because a permanent defect (growth cracks) exceeds 5%.

Example 4: At shipping point, inspection results show 6% bruising. The lot fails because it exceeds the 5% tolerance for the same defect.

Example 5: At shipping point a lot of Shiro Plums show 3% decay, 5% bruising and 2% growth cracks; 6% of the plums measure less than 1 ½ A in diameter. The lot fails because undersize plums exceed the size tolerance (minimum 1 ½ inches) for this variety.

Appendix I

Tolerances used for Canada No. 1 and Canada Domestic Grades

Score against the grade when: P = Permanent Defects, C = Condition Defects
Tolerances Canada No. 1 Canada Domestic
Colour (P) Good Colour Plums - characteristic of the variety Prunes - not less than 75% of the surface area of the prune is of the colour characteristic of the variety Fair Colour Plums - not less than 75% of the plums are of the colour characteristic of the variety Prunes - not less than 50% of the surface area of the prune is of the colour characteristic of the variety
Cleanliness (C) Fairly Clean Reasonably Clean
Drought Spots (P) Free from drought spots Spots affect more than 10% of the surface area
Growth Cracks (P) Free from growth cracks* * Peach Plums - See 7.2 Cracks exceed one per plum or exceed ¼ inch in length or are not well healed
Hail Injury (P) Free from hail injury Hail injury is not well healed or has broken the skin and exceeds ⅛ inch in diameter or has broken the skin and exceeds 3  marks per specimen or affects an aggregate area exceeding 2 inches in diameter
Insect Stings/Injury (P) Free from insect stings/injury Stings/injury exceed 3 per specimen or extends into the flesh or aggregates more than ¼ inch per specimen
Limb Rub and Leaf Marks (P) Free from limb rub and leaf marks Limb rub or leaf marks that affect more than 15% of the surface area
Russeting (P) Rough Russeting that exceeds ¼ inch on a fruit 2 inches in diameter or smaller and 2 inches on fruit greater than 2 inches in diameter Smooth Russeting that exceeds 10% of the surface area Rough Russeting that exceeds ¾ inches on a fruit 2 inches in diameter or smaller and 1 inch on fruit greater than 2 inches in diameter Smooth Russeting that exceeds 25% of the surface area
Scale (P) Scale that exceeds 2 spots or exceeds ¼ inch in diameter in the aggregate Scale that exceeds 5 spots or exceeds ⅜ inch in diameter in the aggregate
Scars (P) Free from scars Scars that exceed 1 per plum or aggregate over ¼ inch in a fruit 2 inches in diameter or smaller or over ⅜ inch on a fruit over 2 inches diameter
Split Pits (P) Split Pits that cause any crack that is unhealed or are healed but aggregate more than ¼ inch in length or that cause the fruit to be not well formed. Split Pits that cause any crack that is unhealed or are healed but aggregate more than ¾ inch in length or that cause the fruit to be not well formed.
Sunscald (P) Free from Sunscald Sunscald that does not blend with the normal background colour or has caused blistering or cracking of the skin
Sunburn (P) Normal Colour of the skin has been materially changed or the skin is blistered, cracked or noticeably flattened. Skin is seriously blistered, cracked or noticeably flattened or when it causes discolouration of the flesh.
Bruising (C) Free from bruises that cause underlying flesh to discolour Bruises that are soft and show discoloured flesh and affect more than 15% of the surface area
Decay (C) Any soft decay or breakdown Any soft decay or breakdown
Discolouration (C) Brown Surface Discolouration Internal Discolouration When areas are sunken and/or discoloured and exceed 2 inches in the aggregate area Free from internal discolouration When areas are sunken and/or discoloured and exceed 2 inches in the aggregate area Discolouration that when a midsection crosswise cut shows an area of flesh over ¼ inch in diameter that is distinctly brown or darker in colour, or when lighter shades or discolouration of the flesh are accompanied by a mushy condition or a district off-flavour or odour.
Shrivelling (C) Materially affecting the appearance Materially affecting the appearance
Skin Breaks (C) Free from skin breaks Free from skin breaks
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