Use of MALDI-TOF MS to Discriminate between Aflatoxin B1-Producing and Non-Producing Strains of Aspergillus flavus

Aflatoxin B-1 (AFB(1)) is one of the most toxic mycotoxins. One of the producers of AFB(1) is Aspergillus flavus. Therefore, its rapid identification plays a key role in various sectors of the food and feed industry. MALDI-TOF mass spectrometry is one of the fastest and most accurate methods today. Therefore, the aim of this research was to develop the rapid identification of producing and non-producing strains of A. flavus based on the entire mass spectrum. To accomplish the main goal a different confirmatory MALDI-TOF MS and TLC procedures such as direct AFB(1) identification by scraping from TLC plates, A. flavus mycelium, nutrient media around A. flavus growth, and finally direct AFB(1) identification from infected wheat and barley grains had to be conducted. In this experiment, MALDI-TOF mass spectrometry with various modifications was the main supporting technology. All confirmatory methods confirmed the presence of AFB(1) in the samples of aflatoxin-producing strains of A. flavus and vice versa; AFB(1) was not detected in the case of non-producing strains. Entire mass spectra (from 2 to 20 kDa) of aflatoxin-producing and non-producing A. flavus strains were collected, statistically analyzed and clustered. An in-depth analysis of the obtained entire mass spectra showed differences between AFB(1)-producing and non-producing strains of A. flavus. Statistical and cluster analysis divided AFB(1)-producing and non-producing strains of A. flavus into two monasteries. The results indicate that it is possible to distinguish between AFB(1) producers and non-producers by comparing the entire mass spectra using MALDI-TOF MS. Finally, we demonstrated that if there are established local AFB(1)-producing and non-producing strains of A. flavus, the entire mass spectrum database identification of aflatoxigenic A. flavus strains can be even faster and cheaper, without the need to identify the toxin itself.

Automated summary

This research aims to develop a rapid identification method for producing and non-producing strains of A.flavus based on the entire mass spectrum. The results show that it is possible to distinguish between AFB(1) producers and non-producers by comparing the entire mass spectra using MALDI-TOF MS. By establishing a local strain database, the identification of aflatoxigenic A.flavus strains can be even faster and cheaper.