Analytical test methods

A variety of tests are used to test for aflatoxin. Some of the more common ones include:

TLC (thin layer chromatography) – uses a simple matrix like cellulose on a solid substrate (e.g. a glass slide) to separate the aflatoxin types. Detection can be by exposing the TLC plate to UV light to fluoresce the aflatoxin, or using a chemical reagent to visualize the aflatoxin.

Pros: Relatively low cost and simple procedure, can separate the different aflatoxin types

Cons: Not very accurate in determining quantity, can involve the use of toxic solvents

HPLC (high performance liquid chromatography) – uses a solvent extraction and high-pressure liquid column chromatography to separate and detect the different types of aflatoxin in the sample.

Pros: Highly accurate and quantifies the different types of aflatoxin; widely accepted procedure from regulatory agencies and health organizations

Cons: More complicated and expensive; requires a high level of skill and infrastructure to operate the specialized equipment

ELISA (enzyme-linked immunoassay) procedure – uses antibodies to detect the presence of aflatoxin.

Pros: Does not require extensive equipment or training, less expensive than HPLC, can do large number of samples

Cons: Usually only detects a single aflatoxin type (e.g., B1), may not be quantitative, requires plate reader

Fluorometry (also called immunoaffinity column) – combines the antibody technology with a fluorometer to quantify the level of color change of the sample extraction after being passed through a filter and then correlates the amount of actual aflatoxin.

Pros: Quantitative results of aflatoxin level; less expensive than HPLC; accepted by some regulatory bodies

Con: Some level of training and supplies are needed to extract and quantify the aflatoxin. Laboratory infrastructure is needed.

Lateral flow Immunochromatographic Strips – provides the ELISA method on a convenient solid support.

Pros: Does not require extensive equipment or training, among the lowest cost methods, can be either semi-quantitative (above or below a threshold, e.g. <10ppb) or quantitative if additional detection equipment is used

Cons: Test strips may be expensive and require specific storage conditions, usually doesn’t determine the aflatoxin type (either AFB1 or estimated total AF)