Carolin Hauser
Fraunhofer Institute for Process Engineering and Packaging IVV, Germany
Title: Hop extracts – A natural antimicrobial for ensuring food safety
Biography
Biography: Carolin Hauser
Abstract
The common hop (Humulus lupulus) produces numerous bioactive compounds, such as the beta-acids. They show lowerrnbitterness than alpha-acids, but high antibacterial activity - especially against Gram-positive microorganisms like Listeriarnspp. Those bacteria can lead to food-borne illnesses and microbial food spoilage. Especially fresh and minimally processedrnfood is not protected against microbial contamination. Antimicrobial substances can minimize the inherent microbiologicalrnrisk of fresh products and are even able to prolong their shelf-life and increase quality. On the other hand, chemicallyrnsynthesized preservatives get more and more rejected by the consumer. Natural substances are preferred instead. In this study,rnwe investigated the potential of beta-acids containing hop extracts as natural antimicrobials for food preservation againstrnselected foodborne pathogens in vitro as well as their activity against Listeria spp. directly on fresh food products. Anotherrnimportant aspect of our investigation was the physicochemical behavior of the extracts at different processing conditions andrnproduct matrices. The experiments showed that Gram-positive bacteria were strongly inhibited by hop extracts containingrnbeta-acids. Gram-negative bacteria were highly resistant against all tested hop extracts. The inhibitory activity of the hoprnextracts against Listeria on food could also be demonstrated. Consequently, antimicrobial hop extracts could be used as naturalrnpreservatives in food applications to extend the shelf-life and to increase the safety of fresh products.