31. August 2021

FFoQSI: Hazardous? Tracking Down Mould with the Aid of DNA Barcoding

Fischer Brot, a successful family-owned bakery firm based in Linz, guarantees its customers a certified quality management system that is practised as a matter of course and focuses on absolute product safety and continual improvement. In order to improve product safety for consumers and working conditions for production staff still further, the bakery began collaborating with FFoQSI in 2017 on a project titled Innovation in Food Processing.

One problem faced by many food producers is mould. Mould spores are ubiquitous: they are in the air everywhere. Small amounts of mould are harmless, both for humans and animals. It only becomes a health risk if it spreads in high concentrations over a particular area. Mould finds ideal growing conditions during the fermentation process in bakeries: high humidity and organic surfaces (fermentation baskets for bread). That is why it was important to Fischer Brot to prevent contamination with mould spores and to hinder the small number of spores in the atmosphere from establishing themselves.

In order to fight a thing you must first know what it is. Conventional methods of identifying moulds are time-consuming and, what is more, can only be carried out by experts with profound specialist knowledge. Consequently, a rapid and robust method was needed that could identify a wide range of moulds. This was achieved by sequencing characteristic DNA sections and comparing them in a database, in other words, DNA barcoding.

The world’s leading working group for mycotoxin research, led by Prof. Dr. Rudolf Krska, took on the task of the qualitative and quantitative identification of mycotoxins. The LC-MS/MS-based method they developed at the Institute of Bioanalytics of the BOKU Department IFA Tulln for simultaneously identifying over 1,000 secondary metabolites (characteristic metabolic products) of fungi had previously been optimized in the course of earlier FFoQSI projects. The moulds were isolated, and eight DNA regions sequenced per sample. Optimization measures made it possible to analyse 12 samples simultaneously. For verification, the protocol was carried out with 37 purchased pure cultures.

The presence of particular moulds detected using DNA barcoding was corroborated by chemically proving the presence of typical metabolite patterns.

Outcomes and effects

The analyses showed a complete absence of hazardous moulds in the bakery; only environmental pathogens were detected of the kind that may be expected to be brought in with goods deliveries. Fischer Brot nevertheless tested additional preventive strategies to reduce contamination and colonization with these undesirable pathogens.

The method that was developed has great potential that far exceeds the original intended purpose. It enables rapid and reliable identification of many types of mould in a wide variety of foods.

For this reason its development will be taken further as part of FFoQSI’s strategic research in order to expand the range of identifiable pathogens and also to enable identification of rare pathogens or pests. The DNA analysis for this will be further expedited in cooperation with another long-time FFoQSI partner, the Center for Health & Bioresources of the AIT, using next-generation sequencing (high-throughput sequencing, NGS). The new method will then be tested on products that have so far been difficult to analyse, such as muesli and dried fruits.