Antimicrobial agents

• Antimicrobial LAB in malting and brewing

Malting is an industrial process where cereal grains are allowed to germinate prior to brewing. During malting, moulds which are frequently detected on cereal grains, can grow rapidly. Many of the mould species commonly found on cereal grains are known to produce significant levels mycotoxins at this stage, resulting in contamination of the the malt. Thus these toxins can get transferred into beer leading not only health problems for the consumer but also to specific processing difficulties. The research outlined here explores natural bio- preservatives produced by lactic acid bacteria which inhibit mould growth. These substances have major potential to prevent mycotoxins reaching the consumer. This work is performed in collaboration with the Department of Microbiology. During a large screening carried out in Microbiology a number of LAB with anti fungal activity have been identified. Genetic characterization of these bacteria is ongoing at the Department of Microbiology.

Our research focuses on optimising the production of these anti-fungal substances, to isolate and characterise them. Subsequently, it will be possible to apply them to malting and other cereal processing industries. We have already optimised the production of these antifungal substances and have isolating the specific molecular components and characterised which are responsible for the anti fungal activity. This work has been carried out in collaboration with University of Lund in Sweden using HPLC and Mass Spectroscopy as analytical tools. We have also been able to sythesis the compounds and are currently using them in a range of food products. A major challenge is obviously to find ways to apply these anti fungal LAB to the malting system and to determine their effect on processing as well as malt and beer quality. We have to-date developed model systems to determine the effect of these LAB have on mould growth.