Gluten Testing for Food Processors

In the past decade, understanding and awareness of food allergens have only grown among consumers. Food allergies can be life threatening for allergenic individuals, as very small amounts of allergenic foods can cause severe allergic reactions. Gluten sensitivity, although different from other allergies, has also received a lot of attention in recent years. While reactions such as anaphylactic shock may not be caused by consuming gluten, the ingestion of gluten sources (wheat, rye, and barley) by a sensitive individual can result in detrimental health effects.

According to The University of Chicago Medicine Celiac Disease Center, one in 20 Americans is affected by celiac disease, which prevents people from being able to safely consume products containing gluten. Additionally, a 2020 study conducted by the University of Nebraska-Lincoln estimated that 25% of American consumers willingly choose to follow a gluten-free diet. As with all food allergens, complete avoidance of gluten sources by sensitive individuals is the most effective preventive measure to avoid an adverse effect.

Allergic individuals rely on the ingredient information declared on the food label to prevent the intake of allergenic foods. Thus, an accurate declaration of ingredients by food processors is critical. In 2014, FDA released new regulations around gluten content, making it the only allergen in the U.S. to have a regulatory set amount—20 parts per millions (ppm)—that a product can contain and still be considered gluten-free. Allergen mislabeling is the No. 1 cause of food safety product recalls, which makes understanding regulations around allergens and having a thorough and robust allergen control program incredibly important for food processors. Controls implemented by the industry prevent a food from being contaminated, and the efficiency of those controls is verified through testing.

Here are four tips to help ensure that food producers are accurately and efficiently verifying the efficiency of their implemented allergen control measures to increase the delivery of safe food for consumers of all diets.

1. Identify the Right Gluten Testing Method

Selecting the right method comes down to risk and, as allergens are incredibly high risk for consumers, producers want to ensure they are using the most diligent test method for their needs. There are numerous methods available to test for allergens, but the four most common include general protein tests, lateral flow devices (LFDs), enzyme-linked immunosorbent assay (ELISA) tests, and adenosine triphosphate (ATP) tests.

• General protein allergen tests. These are commonly used for testing for allergens in the food industry because they are easy to use and provide a quick time to result. These types of tests are qualitative and detect whether any protein is present after the cleaning process, including allergenic protein; however, these tests are not capable of indicating which specific allergen has been detected and are limited to testing on environmental surfaces only. There are a variety of commercially available general protein kits with different sensitivities; however, a highly sensitive method should be preferred for allergen cleaning verification.
• LFDs. Unlike a general protein test, immunoassay-based test methods such as LFDs can identify specific allergenic proteins. While still a highly commercially available qualitative protein test, this method requires producers to use LFDs customized to the allergen they are searching for, such as a gluten lateral flow. While they are not applicable to every food processor and situation, there has been an increase in guidelines looking for the protein-specific methods that LFDs can provide. This testing option is commonly used for cleaning verification because it is easy to use and provides a quick time to result. As an additional advancement compared to general protein tests, some LFD tests on the market have the capability to test a wide variety of sample types, such as raw material, first product off the line, environmental swabs, or clean-in-place rinse water.
• ELISA tests. This is another available protein and allergen-specific testing method that can provide a quantitative result informing producers how much of a specific allergen is present. This can be useful for cleaning validation as well as for food processors working with gluten-free products, because they are able to test how much gluten is present to meet gluten content regulatory levels; however, due to its ability to quantify results, this testing method requires more time, expertise, and equipment, making it a less viable option for daily verification. The ELISA method is beneficial for confirmation testing and pairs well with an initial qualitative test like an LFD, as well as cleaning validations. If food processors do not have the ability to bring this test method in house due to its complexity, they have the option of sending samples to a third-party laboratory to test when needed.
• ATP tests. These types of tests are commonly used for general cleaning verification but are sometimes used to trace present allergens; however, because ATP is easily removable from a surface (unlike proteins) and not all foods that have proteins contain ATP, these types of tests are not a best practice for producers wishing to conduct allergen testing, due to the fact that the allergenic protein could still be present on a surface even if it is free of ATP. Therefore, a protein-specific method is preferred for the safest and most accurate allergen testing programs.

2. Conduct a Method Feasibility Study

No matter which testing method is selected, it’s important to ensure that the method is fit for purpose, a step often overlooked but critical for ensuring proper test method selection. A method feasibility study allows producers to verify that the method they are wanting to use for allergen testing can indeed detect the allergen of concern within the products. When food proteins in a sample undergo food processing steps, such as heat processing or fermentation, the structure of the protein can change. When this happens, the testing method may be unable to detect the allergen proteins, especially immunoassays that rely on specific binding between an antibody and a certain region of a protein. If a method feasibility study has not been completed to verify that the test method is in fact detecting the protein, false negatives, mislabeling, and, potentially, product recalls may result, putting consumers in danger. As a result, conducting a method feasibility study can help protect the food processor and their brand, saving them time, money, and energy on product recalls by ensuring that the chosen test method can accurately detect the allergenic proteins.