<p><i><b>Listeria monocytogenes</b></i> is a Gram-positive, rod-shaped, food-borne bacterium, capable of causing the rare, but potentially fatal, disease <b>listeriosis</b>. <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. <b>Man-Cheester</b> 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.</p>