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Aflatoxins are one of almond growers’ greatest concerns. A chemical produced by certain types of mould, aflatoxins are linked to cancers, and must be eliminated during the growing and handling process.

What are aflatoxins?

Aflatoxins are naturally occurring chemicals produced by certain types of mould, especially aspergillus flavus and a. parasiticus. The main health concern of aflatoxins is their potential carcinogenicity. Chronic exposure to aflatoxins can increase the risk of developing liver cancer.

Aflatoxin-producing mould is common in nature, affecting a number of crops. In almonds,the source of the contamination is from the soil, previously infested almonds (mummy nuts), and Navel Orangeworm (NOW) or other pests. Spores of the mould can be transferred by now and grow on nutmeats that have been damaged. Favourable conditions for mould growth include high moisture content and high temperatures.

Because they are a carcinogen, tolerances for aflatoxins have been established by certain countries to reduce the risk of exposure.

When almonds are tested in the lab for aflatoxins and are found to have levels above the allowable limits by country, the consignment will have to be reconditioned or rejected, with significant monetary losses to the grower and handler.

The Almond Board Of California’s research into minimising Navel Orangeworm to prevent aflatoxins.

The almond industry has programmes and procedures in place to minimise aflatoxins at every stage of production –not just in response to sampling, testing and processing, but also focusing on the orchard environment, where aflatoxin contamination begins and where it must be addressed.

Growers can reduce the potential for aflatoxin growth by minimising Navel Orangeworm (NOW) damage.

NOW prevention can be accomplished by:

Winter sanitation 

The removal of mummy nuts –those that remain on the tree after harvest –before budswell, on or by 1 Feb. Mummy nuts are the prime harbourage of overwintering now, and their removal is the most effective control method. After removal, they should be destroyed by 15 March.

Early harvest 

When almonds are harvested as soon as possible after they mature and are promptly removed from the orchard, a third generation of egg-laying is avoided.

Stockpile management

When in-hull almonds are stockpiled, moisture in the almonds combined with hot weather creates a breeding ground for the aspergillus mould to grow and produce aflatoxins. Following Good Agricultural Practices will help prevent the growth of mould.

In-season treatment 
If winter sanitation and early-harvest guidelines are followed, an in-season treatment for now may not be necessary. A harvest sample can help determine if treatments are required.

UC IPM Pest Management Guidelines

Complete now management guidelines, including treatment options, can be found on the web at the UC IPM website.

With now damage to kernels minimised in the orchard, the California almond industry can continue to provide high-quality product to all markets, and with increased surveillance for aflatoxin by handlers, key export markets that have tolerances are assured a high-quality product that meets their standards.

The market ramifications of aflatoxin outbreaks.

Because they are a carcinogen, tolerances for aflatoxins have been established to reduce risk of exposure. Whenalmonds are tested in the lab for aflatoxins and are found to have levels above the allowable limits, the consignment has to be reprocessed or rejected, with significant monetary losses to the grower and handler.

Pre-export checks (PEC).

One of the largest markets for California Almonds–the European Union (EU)–also has one of the lowest allowable limits for aflatoxin contamination on almonds, currently 10 ppb total, with 8 ppb B1. Mandatory testing of California Almonds imported to EU member since 2007, the California almond industry has had a programme in place fortesting for aflatoxin prior to shipping consignments to the EU. In 2015, the almond Pre-Export Checks programme was implemented under EU Regulation 2015/949 which directs EU port authorities to subject US almond consignments with a PEC certificate to less than 1% controls at the border. Being a voluntary programme, a PEC certificate is not a requirement for import into the EU.

California Almond handlers who ship consignments classified under CN codes 0802.11 and 0802.12 for bulk inshell and shelled lots to the European Union (EU) under the PEC programme are required to sign an annual Memorandum of Understanding (MOU) with the Almond Board of California (ABC). Along with a signed current MOU, PEC participants are given a PEC programme manual and are trained in how to use the ePEC system by ABC staff. Additionally, all PEC participates are subjected to ABC and USDA oversight to ensure programme conformance.

PEC Programme Manual Version 10.2

PEC addendum letter.

The Pre-Export Check (PEC) certificate programme has been a tremendous success since its inception on 1 August 2015. Though we have experienced success, there has been one reoccurring minor issue, international contact information in box I.6 Person responsible for the consignment in the EU. The Almond Board of California (ABC) understands that this information may not always be available at the time the PEC certificate is signed off by the USDA. Once the USDA signs off on the PEC certificate, it is considered permanent and cannot be adjusted. This has caused the PEC certificate to be sent forward with box I.6 vacant. Several consignments have experienced delays at customs upon arrival due to and empty box I.6.

To mitigate this problem, ABC created the PEC addendum letter. The letter can be sent outside the PEC system as an addition to the PEC certificate. Information on the letter looks very similar to the PEC certificate but only contains the relevant fields. Please note that this will not replace the aflatoxin analysis or Annex II (USDA signature page).   Feedback from our European partners, government officials, local port authorities and Foreign Agricultural Service (FAS) offices have all been positive.

PEC Addendum Letter

Save the PDF to your desktop and use Adobe Acrobat to open it. This file will not preview in your internet browser. Only fields highlighted in blue must be filled out by the shipping party (handler, trader, broker, etc.) This is a standardised letter; it needs to be consistent among suppliers. The format and wording should not be changed to avoid confusion among the import authorities. Again, the shipper only needs to fill out the blue highlighted areas.


If you have additional questions please feel free to contact Julie Adams (

USDA-approved Labs For PEC Programme

PEC analyses must be conducted by a USDA-approved laboratory. Only USDA-approved laboratories are authorised to input results into a PEC analysis certificate.
The participating labs have been evaluated and approved by the US Department Of Agriculture, Agricultural Marketing Service, Science And Laboratories Programme.

USDA-Approved Laboratories

View list of approved USDA Labs.