<p1><i>Listeria monocytogenes<i> is a Gram-positive, rod-shaped, food-borne bacterium, capable of causing the rare, but potentially fatal, disease listeriosis. <i>L. monocytogenes<i> can replicate at temperatures as low as 0°C, allowing it to survive in industrial and domestic refrigerators. <i>L. monocytogenes<i> is often found in soft cheeses, making many varieties of cheese unavailable to those who are immunosuppressed. Man-Cheester aims to introduce the <i>agr<i> quorum sensing system from <i>L. monocytogenes<i> into bacteria used in the cheese making process. On detection of AIP, a key quorum sensing molecule of <i>L. monocytogenes<i>, a colour change will occur, causing the cheese to turn purple and alerting the consumer to its contamination. Our concept could be further developed to include other sources of <i>L. monocytogenes<i> contamination, such as meats, vegetables or kitchen surfaces, to prevent as many cases of listeriosis as possible.</p1>