Can aflatoxin really be detected using a flashlight?

There is a short video that says that aflatoxin, a carcinogen, can be detected with an ultraviolet flashlight, because the toxin fluoresces under ultraviolet light. As a result, many people rushed to order such flashlights for fear of accidentally ingesting aflatoxin... However, doing so may not do you any good except to increase your anxiety and make you spend more money on the flashlight... Let's talk about this briefly below.

Excerpted from TikTok

01

What is Aflatoxin

In 1993, aflatoxin was classified as a Class I carcinogen by the World Health Organization's cancer research agency, which can induce liver cancer, stomach cancer and many other cancers. Aflatoxin is a metabolite of Aspergillus flavus and Aspergillus parasiticus. If peanuts, grains, nuts and rice are moldy, they are likely to contain aflatoxin.

This toxin is relatively stable, with a decomposition temperature of up to 268°C, and it is basically impossible to eliminate it during food processing and cooking. Therefore, products processed from moldy food, such as cooking oil, will also contain aflatoxin, and eating them will threaten our health.

Tuchong Creative

Therefore, it is indeed necessary to test aflatoxin in food. So is the method of using a UV flashlight mentioned above reliable? This needs to be discussed in two situations.

02

It may be fluorescent, but that doesn't make sense.

Let’s talk about the first situation first, which is like in the video, using an ultraviolet flashlight to directly illuminate the food and determine whether there is aflatoxin by observing the fluorescence.

Doing this creates two problems.

First of all, aflatoxin can emit fluorescence under ultraviolet light, but it does not mean that all substances that can emit fluorescence under ultraviolet light are aflatoxin. In fact, many bacteria and fungi can emit similar fluorescence under ultraviolet light; some sanitary products and RMB can also fluoresce under ultraviolet light; substances such as vitamin A can also produce similar fluorescence, but these things have nothing to do with aflatoxin.

Fluorescence ≠ aflatoxin | Tuchong Creative

Secondly, if the area illuminated by the flashlight is indeed Aspergillus flavus, and it can emit strong fluorescence visible to the naked eye, then the food is probably very moldy. Even without a flashlight, we all know that moldy food cannot be eaten, and food that has been stored for too long cannot be eaten... Then what is the use of this flashlight (throws it).

03

Is there really toxin? Sorry, I can't detect it with a flashlight.

Since it is not very meaningful to use a flashlight to directly illuminate the food ingredients, is it feasible to use it to test finished food? Let's first see how professionals test for aflatoxin.

Because aflatoxin is extremely harmful to humans and is widely distributed, various foods including grains, beans, nuts, oils, etc. may contain aflatoxin. my country has formulated more than 20 national food safety standards for different foods, and there are at least 7 methods for detecting aflatoxin, including thin layer chromatography, liquid chromatography, etc. Among them, the one that is related to using a flashlight is fluorescence spectrophotometry.

Tuchong Creative

The principle of this method is to use ultraviolet light to illuminate the sample, and then calculate the concentration of the toxin based on the intensity of the fluorescence. However, although the principle seems to be the same, the actual operation is very different. Because the fluorescence spectrophotometry requires the sample to be extracted, defatted, filtered, and then subjected to a series of treatments to enhance the fluorescence effect, and then measured with a very high-precision fluorescence photometer. We use an ultraviolet flashlight and then look at it with our eyes, but we can't tell whether the food contains aflatoxin. And as mentioned above, there may be other substances that emit fluorescence, making you worry in vain.

04

What can we do to stay away from aflatoxin?

In fact, if you want to stay away from aflatoxin, the best way is to stay away from informal processed foods, such as self-pressed oil, because aflatoxin likes to grow on peanuts. If peanuts have not undergone strict safety inspections, the safety of the oil and sauce made from them can be imagined. The response is also very simple, just buy similar products produced by large companies, because the companies have very strict control over the raw materials and more complete product testing procedures.

In addition, we should also pay attention to avoid storing food in a humid environment and not eat moldy or over-stored food. If we find that the seeds or nuts taste bitter or rancid, we should spit them out and rinse our mouths in time, because such a taste means that the seeds or nuts have gone bad or have been contaminated by mold.

Author | Ding Zong

Reviewer | Song Shuang, Associate Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention

Editor | Ding Zong

This article is produced by "Science Facts" (ID: Science_Facts). Please indicate the source when reprinting.

The pictures in this article are from the copyright gallery and are not authorized for reproduction.