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Navigating Allergen Cross-Contamination in Agriculture During the Upcoming Harvest Season: Risk Assessment and Management Strategies

by Martin Candia, Product Manager Romer Labs



As a new harvest season approaches in the northern hemisphere, the agricultural industry faces growing challenges regarding allergen cross-contamination. The co-mingling of crops during this critical period underscores the necessity for meticulous allergen management practices and robust risk assessment measures to safeguard consumers with food allergies. This report delves into the complexities of allergen control in agriculture, emphasizing the significance of proactive approaches to mitigate the risks of unintentional allergen introduction.

Understanding Cross-Contamination and Co-Mingling in Agriculture

During the harvest season, the potential for cross-contamination escalates significantly, particularly when different crops are cultivated in close proximity. Co-mingling occurs when various crop varieties unintentionally mix, leading to the presence of allergens such as wheat, rye, barley, soy, mustard, or peanuts in otherwise safe crops. This can happen at various stages of the agricultural process, including:

  1. Seed Dispersal: In regions where, diverse crops are grown near each other or where crop rotation is practiced, unintended mixing of seeds can occur. This co-mingling from the outset can introduce allergens into the crops from the beginning.
  2. Harvesting, Transport, and Storage: The risk of cross-contamination is particularly high during the busy harvest period when equipment usage intensifies. Shared harvesting equipment, transport vehicles, and storage facilities, if not adequately cleaned between uses, can transfer allergens from one batch to another.
  3. Initial Processing: Processes such as milling, drying, or freezing can concentrate allergen contamination. Shared processing equipment that is not thoroughly cleaned between batches can inadvertently introduce allergens into otherwise safe crops.

Common co-mingling scenarios include wheat mixing with soybeans or oats, soybeans contaminating wheat or corn, and rapeseed and mustard being found in wheat and barley. These instances highlight the critical need for stringent measures to prevent contamination. The detection of cross-contamination plays a central role in preventing allergens from being included in products that do not list them as ingredients. More importantly, it ensures that products labeled as "free of" these allergens remain safe for consumers.

The Significance of Effective Allergen Management

With the imminent harvest season on the horizon, the importance of effective allergen management cannot be understated. The accurate labeling of allergens in agricultural products is paramount to ensure consumer safety and regulatory compliance. Failure to implement allergen control measures during this period can have severe consequences for individuals with food allergies, underscoring the imperative for proactive management strategies to mitigate risks.

Risk Assessment and Mitigation Strategies in Preparation for Harvest

As agricultural stakeholders gear up for the upcoming harvest season, a comprehensive allergen management plan is essential. This plan should include thorough risk assessments and control measures at every stage of production:

  • Geographical Crop Distribution: Identify which crops are grown in the same region. Establishing buffer zones between fields can reduce seed dispersal and co-mingling.
  • Crop Rotation Practices: Monitor and manage crop rotation schedules. Removing contaminant plants from fields can help prevent cross-contamination.
  • Physical Characteristics of Crops: Implement cleaning, size, and color sorting processes before storage to separate potential contaminant crops from primary crops.
  • Equipment and Machinery Use: Ensure thorough cleaning, visual inspection, and allergen testing of equipment and machinery shared between different crops.
  • Storage Practices: Assess the storage of crops in shared spaces. Implement rigorous cleaning, inspection, and testing protocols to prevent cross-contact.
  • Testing Methods: Choose appropriate testing methods for allergen detection. For example, antibodies used to detect mustard may cross-react with rapeseed, complicating the testing process. In such cases, PCR methods may offer a reliable alternative.

Furthermore, educating farm workers and staff on allergen control practices is crucial to uphold food safety standards during this pivotal period.

In cases where the presence of a co-mingled allergen cannot be excluded, its concentration should be determined. If necessary, precautionary allergen labeling (PAL) should be applied to inform consumers of the potential allergen presence. This step is crucial for ensuring consumer safety, especially for those with food allergies.

Comprehensive Approaches to Allergen Testing

Allergen testing is crucial for managing contamination risks and validating control measures. However, no single method can be considered the gold standard for all situations. Different testing methods have specific advantages and limitations:

Lateral Flow Devices (LFDs): LFDs are cost-effective and fast. These are excellent tools for quickly verifying the efficacy of cleaning procedures and monitoring the presence of allergens. However, they cannot quantify allergen levels, possibly limiting the information they provide.

ELISA (Enzyme-Linked Immunosorbent Assay): ELISA is a robust method for allergen detection, providing accurate allergen concentrations. However, these concentrations must consider the differences in calibration materials and antibody reactivity. ELISA is ideal for validating allergen management and control programs. In parallel, Lateral Flow Devices (LFDs) should be used to establish correlation between the methods, as LFDs are preferred for ongoing cleaning verification.

PCR (Polymerase Chain Reaction): PCR is effective in covering gaps of immunological methods like LFDs and ELISA, especially when dealing with issues like antibody cross-reactivity. PCR provides precise allergen detection in challenging scenarios.

Regulatory Compliance

As harvest season ramps up, understanding and adhering to regulatory requirements in the countries where crops are sold or exported is crucial. Each market may have specific allergen labeling regulations and contamination thresholds that must be met to ensure compliance and avoid legal repercussions. It is essential to stay updated on these regulations to maintain consumer safety, uphold industry standards, and avoid potential fines or product recalls.


The co-mingling of crops and associated allergen contamination is a complex challenge, particularly during the high-activity harvest season. However, with a robust allergen management plan that includes comprehensive risk assessments, effective testing protocols, and adherence to regulatory standards, the agricultural industry can significantly mitigate these risks.

Ensuring food safety for allergic consumers requires a multifaceted approach involving meticulous planning and execution at every stage of production. By staying vigilant and proactive, the industry can navigate the challenges of co-mingling and allergen contamination, ultimately contributing to a safer food supply for all.

As the harvest season approaches, now is the time to reinforce these measures, ensuring that crops are harvested, processed, and stored with the highest standards of allergen safety. This proactive approach not only protects consumers but also upholds the integrity and reputation of the agricultural industry.

Published on:

Food Allergens

About the author

Martin Candia - Product Manager

Martin Candia joined Romer Labs in November 2018 as Product Manager of the Allergens division and is involved in method development, validation design, and application support in allergen testing. He provides scientific and technical advice to sales staff worldwide and conducts workshops and webinars for customers. He has extensive experience in the field of allergies and has been involved in projects aimed at developing both prophylactic and therapeutic treatments for allergies in children and adults. In the past, he has focused particularly on cow's milk allergy and modulating allergic response through the use of peptides.