Testing for Corn Mold

Summary

This video guides viewers through the process of testing corn for aflatoxin, a harmful toxin produced by mold. It outlines essential lab safety procedures, such as wearing gloves and goggles, and proper handling of materials. The procedure involves examining corn for visible mold, using UV light to detect aflatoxin, and performing a presumptive test with methanol to extract the toxin. After preparing samples and diluents, a test strip indicates the presence of aflatoxin, highlighting the importance of detecting this toxin to protect human and animal health.

Takeaways

• 🧪 Always follow basic safety procedures in the lab, including handwashing and wearing gloves and safety glasses.
• 🌽 Mold on corn can produce aflatoxin, a harmful toxin that can make people and animals sick.
• 🔍 Aflatoxin glows under UV light, allowing for preliminary detection before further testing.
• 🚜 Aflatoxin can develop on corn both prior to and after harvest due to specific mold growth conditions.
• 💧 To test for aflatoxin, corn must be mixed with a liquid solvent, typically methanol, to extract the toxins.
• ⚗️ A graduated cylinder is used to measure liquids accurately for the testing process.
• ⏲️ Timing is crucial in testing; the corn mixture must sit for exactly five minutes before proceeding.
• 📏 A diluent is used to dilute the corn mixture for easier testing with a test strip.
• 🧪 The test strip indicates the presence of toxins; if the middle strip is as dark or darker than the bottom strip, the sample tests positive.
• ❌ Contaminated corn has very limited uses and may need to be destroyed to prevent harm.

Q & A

What is aflatoxin, and why is it important to test for it?

Aflatoxin is a toxin produced by specific molds on corn that can cause illness in humans and animals. Testing for aflatoxin is crucial to prevent contaminated food from entering the food supply.

What are the basic safety procedures to follow in the lab?

Basic safety procedures include washing hands before and after handling materials, wearing gloves and safety glasses, avoiding eating or drinking in the lab, securing loose clothing and hair, and cleaning equipment after use.

How does mold get on corn?

Mold can contaminate corn both before harvest, if conditions favor mold growth, and after harvest, particularly if the corn is not properly dried.

What initial observations indicate the presence of mold on corn?

The initial observation of visible mold on the corn and the presence of bright spots under UV light suggest potential contamination with aflatoxin.

What materials are used to prepare the corn sample for testing?

To prepare the corn sample, 10 grams of coarsely ground corn and 50 milliliters of methanol are used to extract the toxins.

What is the purpose of using methanol in the testing process?

Methanol acts as a solvent to extract aflatoxin from the corn sample, converting the solid sample into a liquid form suitable for testing.

How long should the corn and methanol mixture be shaken, and what comes next?

The corn and methanol mixture should be shaken for 30 seconds and then allowed to sit for 5 minutes to ensure proper extraction of the toxins.

What is a diluent, and why is it used in this testing procedure?

A diluent is a liquid used to dilute a sample, making it easier to work with. In this procedure, it helps prepare the corn solution for accurate testing.

How do you know if the test for aflatoxin is successful?

The test is successful if the indicator strip is visible and if the middle strip is as dark as or darker than the bottom comparison strip, indicating the presence of aflatoxin.

What should be done with corn if aflatoxin is detected?

If aflatoxin is detected, the corn has very limited uses and may need to be destroyed to prevent health risks to humans and animals.