"Culturing bacteria in liquid media has some drawbacks. Properties of bacteria are not
visible in liquid media and presence of more than one type of bacteria can
not be detected. Liquid media tend to be used when a large number of
bacteria have to be grown. Culture media are suitable to grow bacteria when the numbers in the inoculum is suspected to be low. Inoculating in theliquid medium also helps to dilute any inhibitors of bacterial growth"....microrao.com.....
"liquid media tend to be used when a large number of bacteria have to be grown".....pastry chefs use gelatin with cream anglaise as base for mousse. The problem lies when creme anglaise is just "tempered" and not cooked all the way through to "a la nappe". A poor sanitation procedure of pulling out mousse bases from the coolers and letting it sit out for use all day encourages bacterial growth. Gelatin is a protein that bacteria can digest and with that, it becomes liquid, therefore bacterial growth will be at a level not safe for consumption. Also, gelatin will start to liquefy at room temperature