1. Walnuts: Possible Defects

2. Reception
 Upon receiving the goods, we recommend
that you carry out an inspection of the
walnuts as infestation is possible at any
stage.
 How much to sample?
1. Randomly select 2 cartons per pallet
2. Upturn to check the corners and bottom for
webbing, shell fragments, etc.
3. Sample 500g from each cartons

3. Typical Walnuts
 Light to Amber in colour
 Soft yet crisp texture
 Mild sweet flavour

4. Typical Walnut Colour
 Walnuts are classified into 4 colours
1. Extra light
2. Light
3. Light/Amber
4. Amber
 Darker nuts have higher oil content

5. Discolouration
 Abnormal colouration that covers more than 1/8th
of the surface of
the kernel and is of a colour in pronounced contrast with the colour
of the rest of the kernel [dark blemishes or areas of discolouration]
(UNECE)
 Can be caused by a fungus (Xanthomonas campestris) that thrives
in prolonged wet weather and hull injury
Discoloured Typical Typical

6. Insect Damage
 Visible damage caused by insects or other animal parasites the presence
of dead insects or insect debris (UNECE)
 Navel Orange worm presents the biggest threat
 Internal damage and can be difficult to spot early on (inspect a random
sample for signs of internal damage)
 Serious infestation causes webbing (check corners of containers for this)
 Look for damage (ie. holes, discolouration) to the nut ‘meat’
 Refer to Reception slide for advise on inspecting goods

7. Mould Damage
 Mould filaments that are plainly visible to the naked eye
(UNECE)
 Mould damage can occur when moisture levels are too high
 Can lead to growth of aflatoxins caused by Aspergillus
 Control with proper storage conditions
 Dry, cool, air tight containers

8. Shrivelled Kernels
 Kernel which is seriously shrunken, wrinkled and tough (UNECE)
 Can be caused by an infected tree (ie: anthracnose fungus)
 Shrivelled kernels are more susceptible to other damages
 Damage: 1/8th
of kernel shrivelled, Serious Damage: 1/4th
of kernel
shrivelled, Very Serious Damage: more than 50% of kernel shrivelled
(USDA Standards)

9. Septum
 The septum develops between the two hemispheres of the walnut and
connects the nut to the shell.
 Very hard, like the shell
 Spiky and can easily stick in ones throat
 Can be very dangerous, so proper removal is important
 Can make it to final product as it is of similar colour and can be missed
by laser sorters, therefore, visual inspection can help catch this

10. Foreign Matter
 Any matter or material not usually associated with the
product [ie: Adhering Shell, Hull, Dirt, dust] (UNECE)
 USDA classified foreign material as serious damage
 USDA Standards: http://ucfoodsafety.ucdavis.edu/files/175751.pdf
 UNECE Standards:
http://www.unece.org/fileadmin/DAM/trade/agr/standard/dry/Standards/DDP02

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