Pseudomonas bacteria is a contaminant that can spoil milk and result in the discolouration and off-flavours in cheese - it is a challenging bacteria to control in a dairy plant. It needs oxygen to grown and can survive & grow in cold environments, thrives in wet and damp conditions and can enter a dairy plant in a number of ways through dirt, dust, milk or water.
Studies have found that the most common way that Pseudomonas contaminates milk and dairy products is through post-pasteurization contamination. Even after heat treatment Pseudomonas enzymes may still be active and product off-flavours in cheese or dairy products.
** Refer to the article attached for more information on how to detect and prevent Pseudomonas contamination.