For growers and handlers alike, aflatoxin is a significant hazard to your nut products. While aflatoxins pose a greater risk to developing countries than first world countries, they are carcinogenic toxins and pose serious health risks to consumers if not managed. An inability to adhere to regulations regarding aflatoxins may result in a costly recall or the rejection of your exported product. This is especially true for exports as stricter tolerance limits are not uncommon in other countries. Developing a thorough understanding of the fundamentals of aflatoxins in almonds and pistachios and their impact on your export efforts will aid in the ultimate goal: providing safe food to the consumers we work tirelessly to protect.
What is Aflatoxin?
Aflatoxins are mycotoxins, chemical compounds created by fungi or mold. These toxic, carcinogenic metabolites are predominantly produced by two species of Aspergillus fungi: Aspergillus flavus and Aspergillus parasiticus. Aspergillus flavus primarily produces aflatoxin B1 (AFB1) and B2 (AFB2), while aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) are produced by both Aspergillus flavus and Aspergillus parasiticus.
Aflatoxin B1 is the most toxic of the four basic forms due to its chemical structure which lends toward quick absorption in the gastrointestinal tract, the ability to produce mutations and genetic damage, potency, and its general carcinogenicity.
Why Should We Care About Aflatoxins?
According to the FDA, regular consumption of aflatoxin can “increase your risk of liver cancer, cause birth defects, and lead to kidney and immune system problems.” And if you are “eating food containing a large number of aflatoxins at one time” it “can lead to liver failure and even death”. Consumer risk is the reason aflatoxins are regarded as seriously as they. As professionals in the food industry, our primary concern should always be the health and safety of our consumers.
But why are aflatoxins so challenging to dispose of?
Causes of Aflatoxin Contamination
With no viable processing step for a finished product that has aflatoxin residues, the need to control and prevent this situation is imperative. The first step in reducing contamination is to acquire a thorough foundation of its root causes. Here are the top five factors contributing to aflatoxin poisoning in almonds and pistachios:
Early Hull/Shell Split
: Early hull split has long been identified as elevating the risk for aflatoxin formation (Doster and Michailides, 1995). A great portion of that reasoning stems from the process of shell splitting which occurs once the pistachio has reached the end of its maturation cycle. Prior to the hull split, the shell fully encases the pistachio kernel, shielding it from exposure and an increased susceptibility for mold and insect infestation. Without the full shell encasing, aflatoxin has easy access to begin its contamination process.
Environmental Factors
Climate is the predominant culprit for spreading aflatoxin. The Aspergillus fungi are abundant in warm and humid climates, wreaking the most havoc on crops in the field, during harvest, and post-harvest in storage. The climate which promotes the growth of the fungi is the same one required for most nut production, creating a challenge for growers.
Drought stress is also known to increase the susceptibility of almonds and pistachios to fungal infection. Water deficient soil impairs the defense mechanisms of plants while simultaneously creating a favorable environment for aflatoxin production.
Insect Damage
The damage created by insects contributes to the creation of conditions that promote aflatoxin by providing entry points for fungal growth. For almonds and pistachios, the ominous Navel Orangeworm, Amyelois transitella, is one of the most formidable insect invaders.
The mummy nuts left from the previous harvest season are where the Navel Orangeworm (NOW) moths typically lay their eggs. The physical damage creates openings on the nut surface for fungal infection. These eggs survive the winter season and hatch in warmer climates. They then feed on the surrounding nutmeat, creating more entry points. They leave excrement and other waste which aflatoxins can use as a nutrient source, increasing aflatoxin production. NOW contribute to weakening the nut’s protective outer layer, which protects the nut from moisture and humidity. By weakening this protective layer, NOW create localized microenvironments suitable for fungal growth. Research shows the number of feeding sites correlates with the levels of aflatoxin contamination; the more feeding sites per nut, the higher the AFB1 levels are.
Poor Agricultural Practices
Many agricultural practices can lend to aflatoxin infestation. Soil, for instance, can be a source of contamination. If the soil contains fungal spores, the crop can become infected. As mentioned, previously infested mummy nuts are a cause for concern because of the damage created by NOW moths. Poor handler practices such as insufficient sorting, cleaning, or processing can result in a higher prevalence of contaminated nuts, potentially tainting the rest of the batch or lot.
Inadequate Storage Conditions
The primary concerns with storage are moisture and climate exposure. Damp, warm, or humid storage environments should be avoided to decrease fungal growth probability. If proper storage practices are not in place, the almond and pistachio nuts are at higher risk for fungal infection.
Aflatoxin Prevention and Management Solutions
The best strategies to combat aflatoxin are prevention and management-based. This includes minimizing pest pressures, proper agricultural practices, proper storage, employee training, and testing conducted at a USDA-certified lab, such as Safe Food Alliance.
Minimize Pest Pressures
The main concern should be the Navel Orangeworm. Follow an aggressive IPM (Integrated Pest Management) program, including insecticide sprays. Decrease the number of mummy nuts left once harvest ends. Implement a winter sanitation protocol annually.
The California Department of Food and Agriculture (CDFA) partnered with the USDA, the California tree nut industry, and other interested parties to create a Navel Orangworm Program. The NOW program was developed to reduce damage caused by NOW within California. It is a multi-pronged program that involves the release of sterile NOW and other mating disruption techniques and is a great resource for understanding and reducing NOW populations.
Good Agricultural Practices
These practices include optimal irrigation, timely harvest, sorting, and disposal, along with the use of atoxigenic strains of Apsergillus flavus as biopesticides to reduce aflatoxin levels.
- Irrigation: Practicing proper irrigation techniques such as maintaining the optimal soil moisture levels will lower the risk of drought stress and fungal infection.
- Timely Harvests: Do not delay harvest as this leads to increased aflatoxin contamination. The longer harvest is delayed the higher the incidence of aflatoxin.
- Sorting and Disposal: Separate contaminated nuts from those that have not been contaminated to prevent cross-contamination. Then dispose of contaminated nuts safely to prevent exposure.
- Biocontrol: Strains of Aspergillus flavus that do not produce aflatoxin such as AF 36 can be applied to the orchard, outcompeting the toxin-producing strains and reducing potential contamination.
Proper Storage
Nuts should be stored in a cool, dry environment to minimize the risk of fungal growth and aflatoxin production. Remember, aflatoxin thrives in warm environments. Avoid this with proper ventilation.
Engage in Trainings
Knowledge is power! Obtain the necessary training to grow and process your crops safely. Begin with the foundations of Good Agricultural Practices (GAP) and Good Manufacturing Practices (GMPs), then increase your understanding of prevention and control measures for hazards with Hazard Analysis and Critical Control Points (HACCP) and the FSMA Preventive Controls Rule for Qualified Individuals (PCQI).
Participate in food safety training programs from the accredited experts in the field, such as those offered by Safe Food Alliance.
Lab Testing from a USDA Approved Laboratory
Using a USDA-certified lab for aflatoxin testing is essential for detecting contamination and preventing unsafe products from reaching consumers. These labs operate under rigorous quality management systems and accreditation, ensuring the highest analytical performance and competency standards. By working with a certified lab, producers can trust the test results and make informed decisions about the marketability and safety of their products.
Effects of Aflatoxin Contamination on Exports
Even with these precautions in place, aflatoxin may still be a hinderance in your export efforts. As it concerns aflatoxins, the key element to a successful export is to know your requirements and tolerances. Both pistachios and almonds have programs specifically designed to address concerns about aflatoxin contamination in regard to the safety and quality of exports. This includes adhering to the ppb total and AFB1 limits.
PEC Program
For almonds, the Pre-Export Check (PEC) program was initiated to replace the Voluntary Aflatoxin Sampling Plan (VASP) in 2015. PEC provides an aflatoxin analysis certificate to approve a product meets the predefined criteria. This criterion specifies the aflatoxin testing has been completed in accordance with European Union protocols and at a USDA approved lab. Although the certificate is not mandatory for export, it is perceived highly and consignments in possession of this certificate are controlled at less than 1% in comparison to those without it who will be randomly controlled at the discretion of the import authorities. For more information, visit the Almond Board website. You can keep up to date on aflatoxin tolerances with resources provided there such as the International Aflatoxin Tolerances Sheet.
PEAR Program
The pistachio program, PEAR, was initiated as a combined effort between industry professionals and regulatory officials in the early 2000s. The PEAR (Pistachio Export Aflatoxin Reporting) program initiates a shipping tolerance acceptable to European Union member states, required sampling, testing of pistachio products in only USDA-approved laboratories, and an audit of the shipping process. A product that meets these requirements will receive the PEAR certificate of analysis (COA). Unlike the PEC program, the COA for the PEAR program is mandatory to conduct exports. For more information on conducting proper pistachio exports under PEAR, visit the Administrative Committee for Pistachios.
Export Wrap Up
Inability to follow the regulations designated in the PEAR and PEC programs may lead to costly recalls or product rejections after export. Product rejections pose challenges for those with no prior experience to them. Will the product be brought back? Can the product be resorted? Where will it be sorted and retested? How much will this rejection impact the amount of product that is sellable?
These and many more questions may arise. But rest assured, the answer is simple: reach out to a Safe Food Alliance lab representative.
Safe Food Alliance is your partner in Aflatoxin Testing
We have the answers to these questions and many more. We will help guide you through the process. With multiple decades of experience testing aflatoxins and handling aflatoxin-related concerns, you can trust we have the knowledge to guide your almond and pistachio exports. We were one of the first labs to get approval under the USDA-certified lab programs and we have decades-long, positive relationships with the European Union.
Safe Food Alliance is the trusted partner for many growers and handlers of almonds and pistachios in need of precise and dependable laboratory testing services. Our cutting-edge technology and methods guarantee that your food items undergo thorough safety and quality tests. By collaborating with us for comprehensive food safety solutions, you safeguard your brand reputation and the health of your consumers.
