The following excerpt has been taken from the New Zealand Truffle Association's HEA Approved Export Marketing Strategy. It outlines the Export Grading Standards required for the Black Périgord truffle (tuber melanosporum) and is the standard currently used here at George's Truffles for grading and pricing all truffle we sell in New Zealand.
6. Schedule of Requirements - Standards for Export of Truffles
6.2 Tuber melanosporum
6.2.1 Definition of produce
This standard applies to truffles, i.e. ascocarps (fruiting bodies) of the Périgord black truffle (Tuber melanosporum Vittadini) to be supplied fresh to the consumer. Truffles for industrial processing are included.
6.2.2 Provisions concerning quality
The purpose of the standard is to define the quality requirements of truffles at the export control stage, after preparation and packaging and a recommendation for local sales.
6.2.3 Minimum requirements
The truffles must be:
of New Zealand origin,
firm, clean, intact – slight superficial cut on whole truffles is not regarded as a defect,
free from pests and major damage caused by pests, rotting or deterioration such as to make it unfit for consumption,
free of any visible foreign matter and soil free,
free from damage caused by frost,
free of abnormal wetness on the surface, aromas and/or flavours that may indicate decay,
free of any major physical damage, and
able to withstand transport and handling and arrive at their destination in a satisfactory condition.
6.2.4 Maturity requirements
The aroma must be sufficiently developed and must display satisfactory ripeness for the grade allocated.
The truffles are classified in four classes defined below:
Truffles in this class should be of the highest quality. They should be of regular shape and sufficiently mature to have the characteristic aroma, taste and colour of the species, with only very slight damage.
Truffles in this class may include those that have been damaged or broken but are sufficiently mature to have the characteristic aroma, taste and colour of the species. They may have some shape imperfections and predator damage. It includes truffle pieces greater than 100g.
Truffles in this class comprise smaller truffle pieces, which have been broken or cut from larger truffles but are sufficiently mature to have the characteristic aroma, taste and colour of the species, but will contain defects and damage marks.
Truffles in this class are immature truffles with little or no aroma and primarily aimed at the manufacturing industries.
The photo-based measurable criteria will be established by the New Zealand Truffle Association and trialed during the 2017 export season.
6.2.6 Provisions concerning sizing
Size is determined by the weight of truffle and is graded into the following bands:
0 – 20g
20 – 100g
100 – 250g
250 – 750g
Special (750g +)
A batch/shipment of immature truffles each weighing 0–20g would be graded D 0-20.
A batch/shipment of mature truffles each weighing about 500g would be graded A 250-750.
A parcel of badly damaged truffles each weighing about 75g would be graded C 20-100.
A mature truffle weighing 1.1kg would be graded Special A 1.1kg.