Aflatoxins are one of the biggest threats to producing safe, high-quality almonds that growers and processors face. Consuming almonds and other nuts contaminated with aflatoxins can increase the risk of cancer and other health problems, while a single rejected consignment due to aflatoxin contamination can cost $10,000 in expenses, and more if the shipment must be destroyed.
Given the importance of almonds to the U.S. and California economies, understanding aflatoxins and aflatoxin testing is vital for your business. Here’s what you need to know.
Aflatoxins are naturally occurring, but potentially carcinogenic, mycotoxins produced by certain molds, primarily Aspergillus flavus and A. parasiticus. They can contaminate several economically important crops in California, including almonds, figs, and pistachios. There are four major aflatoxins:
Aflatoxins in almonds and other crops can cause serious health problems. Chronic exposure can lead to increased risk of liver cancer; reduced immune function; and liver, kidney, and neurological damage. For that reason, most countries have established tolerances for aflatoxin contamination on almonds and other nuts.
Aflatoxins in almonds was a minor concern until recently. However, severe drought throughout California combined with increased infestation of the Navel Orangeworm pest have created conditions favorable to aflatoxin formation.
Almonds can become contaminated a few different ways, including the following:
Increased moisture content combined with high heat create conditions favorable to mold growth. Mold spores can spread and grow on developing almonds, causing aflatoxin contamination and almond mold.
Navel orangeworm infestation can lead to aflatoxin in pistachios, almonds, and other nuts.
Most countries set a low permissible level of aflatoxin in almonds due to the potential health risks. These different thresholds only add complexity to an industry already trying to manage drought, supply chain problems, worker shortages, and low almond prices.
A few notable countries and their permissible level of aflatoxin in almonds are shown here, including the two largest importers of almonds outside the European Union (India and China). View the entire list here.
The best way to deal with aflatoxin contamination in almonds is to prevent it. The Almond Board of California recommends following Good Agricultural Practices, which can go a long way toward reducing and preventing aflatoxin contamination.
Here are some best practices for reducing aflatoxin contamination:
This pest can create larval boring wounds in the nutmeat that allow infection by aflatoxin-producing fungi. Failing to control navel orangeworm leads to increased aflatoxin contamination in almonds.
According to the Almond Board of California, here are a few best practices you can do to help reduce navel orangeworm infestation:
Harvesting almonds as early as possible helps prevent a third generation of egg-laying, which helps reduce navel orangeworm infestation.
Harvest is a prime opportunity to introduce contamination that results in the proliferation of microorganisms that produce aflatoxins or salmonella. Take care to inspect and clean vehicles and equipment to help avoid cross-contamination.
Excess moisture on the orchard floor can lead to the proliferation of mold and bacteria. It helps to keep the floor as level as possible to avoid low areas where water can collect. If standing water is present, avoid harvesting until it has dried.
Allow nuts to remain spread out on the orchard floor to dry after they’ve been shaken from the tree. If they get rained on, allow time for drying before sweeping. If there isn’t time, they should be allowed to dry at the processing plant after being picked up.
Your profitability depends on strict aflatoxin surveillance, and a major component of that is running an aflatoxin test at a reputable and accredited third-party laboratory. Proper sampling and testing satisfies regulatory agencies, safeguards your bottom line and helps produce the safe, high-quality almonds for which you’re known.
Proper sampling requires generating an aggregate sample comprised of incremental samples taken from throughout the production lot. These smaller samples are finely ground to produce a homogenous sample for testing, which maximizes accuracy. European officials, for example, prescribe a sampling protocol that requires one 20 kg aggregate sample of all nuts, one 20 kg sample for nuts that need further processing, and two 10 kg samples for ready-to-eat nuts. This protocol helps ensure accurate results.
Since the European Union is the destination for much of California’s almond crop, the California almond industry created the almonds Pre-Export Checks (PEC) program in 2015, which requires aflatoxin testing prior to shipment. While you don’t need a PEC certificate to export almonds to the EU, it helps speed your shipment, with almond consignments with a PEC certificate subject to less than 1% controls at the border.
Aflatoxin testing for the PEC program must be conducted by a USDA-approved laboratory, such as Certified Laboratories, which has a location in Turlock, California, the heart of the almond industry.
When performing an aflatoxin test for almonds and pistachios, Certified Laboratories use the industry-standard AOAC 991.31, A-F, H method. Here's a look at how aflatoxin testing for almonds and tree nuts is performed.
The aflatoxin is extracted using a methanol solution, this solution is then filtered, diluted, and applied to an immunoaffinity column (IAC). The aflatoxin in the solution will bind to the column as it flows. The chemist then follows up with water on the column to rid it of any impurities.
The aflatoxin is then removed from the IAC using 100% methanol. The sample is then diluted with water and injected into a High Performance Liquid Chromatography (HPLC) machine. The HPLC will separate the B1, B2, G1 and G2 aflatoxins, and it is equipped with a fluorescence detector (FLD) to detect the aflatoxin and provide the results in parts per billion (PPB).
Certified Laboratories also has a benchtop fluorometer that can read the total aflatoxin (without separating the individual aflatoxins). Contact us with any questions about aflatoxin testing for almonds or other nuts.
Given the potential health risks of aflatoxins, salmonella and other contaminants, the United States and Canada require almonds to be pasteurized. A pair of salmonella outbreaks in the early 2000s prompted the USDA to require almond pasteurization in the U.S. beginning in 2007.
There are a few different methods processors use to pasteurize almonds to kill aflatoxins, salmonella, and other contaminants, including the following:
FDA-Approved Methods
Non-FDA-Approved Methods
Whichever process is used, it’s important that it be validated to demonstrate your almonds or other products are produced in a safe manner. Running a process validation for almonds takes a lot of work and involves several steps, all of which must be done according to regulations and properly documented. It also requires working with an approved process authority who is experienced to handle any validation accepted by the Almond Board of California.
The team of experts at Certified Laboratories includes process authorities recognized by the Almond Board of California. We have the expertise and credentials you need to validate your processes and maximize product quality and safety. Download our process validation checklist so you know what to expect before your validation.
As we said earlier, obtaining a Pre-Export Check (PEC) certificate through the Almond Board of California requires using a USDA-approved laboratory for aflatoxin testing, such as Certified Laboratories. Here are a few additional considerations when deciding on a lab to perform aflatoxin testing:
With a location in Turlock, California, the heart of almond country, Certified Laboratories delivers the localized service you need to produce and process almonds safely.
Contact us with your questions about aflatoxin testing and we’ll be glad to help.