Can high temperature kill Aspergillus flavus?

Aflatoxin is a relatively common fungus. As it is summer and the climate is relatively hot, it is very easy to reproduce and grow in food. It can exist in moldy peanut kernels, rice, etc. It is highly toxic and carcinogenic. Be careful not to eat moldy food, and actively prevent food mold and the production of aflatoxin. So, if there is aflatoxin, can high temperature kill it? Let me introduce it to you in detail.

The decomposition temperature of aflatoxin is 268℃. Ultraviolet rays are destructive to low concentrations of aflatoxin. The standard practice is to expose it to high temperature (100-120℃) for a long time, such as high-pressure sterilization and calcination, to inactivate most of it. Press the valve and boil it for 20 minutes. However, aflatoxin produced by Aspergillus flavus is very stable at high temperatures and is difficult to decompose or react with other substances. It is still toxic.

Low temperature can only inhibit its growth, but cannot kill it.

Suitable temperature for the growth of Aspergillus flavus

Aspergillus flavus is a common and dominant mold in warm areas. Its growth temperature range is between 4-50℃, and the optimal growth temperature is 25-40℃. The minimum temperature for aflatoxin formation is 5-12℃, the maximum is 45℃, and the optimum temperature is 20-30℃ (28℃). In meat products, aflatoxin will not be produced when the temperature is below 10°C.

Aflatoxin precautions

(1) If the room temperature is lower than 20℃ or the reagents and samples have not returned to room temperature (20~25℃), the OD values ​​of all standards will be low.

(2) If the wells of the plate dry out during the washing process, the standard curve will not be linear and the repeatability will be poor. Therefore, after washing the board and patting it dry, proceed to the next step immediately.

(3) Each reagent must be shaken well before use.

(4) The reaction termination solution is 2M hydrochloric acid. Avoid contact with skin.

(5) Do not use expired test kits; do not mix expired test kits with other test kits; do not exchange reagents from test kits with different batch numbers.

(6) Signs of reagent deterioration: If the color developing reagent has any color, it indicates that the reagent has deteriorated and should be discarded. When the absorbance (450/630nm) value of the 0 standard is less than 0.5 (A450nm<0.5), it indicates that the reagent may have deteriorated.

(7) After adding the color developing solution, the color development time is generally 15 to 30 minutes. If the color is lighter, the reaction time can be extended to 35 minutes (or longer), but not more than 40 minutes. On the contrary, the reaction time is shortened.

(8) The optimal reaction temperature of the kit is 25°C. Temperatures that are too high or too low will cause changes in the absorbance value and sensitivity of the test.

Quick identification

Aflatoxin tastes very bitter. If you taste the bitterness when eating foods such as peanuts and walnuts, spit them out immediately and rinse your mouth. Moldy peanuts, walnuts, etc. are prone to produce aflatoxin.

Precautions

Anti-mold: Mold growth and reproduction requires a certain temperature, humidity, oxygen and moisture content. If one of these factors can be controlled, the purpose of anti-mold can be achieved; detoxification of aflatoxin; grain and oil foods whose content exceeds national standards must be detoxified. Currently commonly used detoxification methods include physical removal, chemical removal and biological removal: a physical removal b chemical removal c biological detoxification method.