Yes, increased turbidity of the tube is a normal result of the growth of Listeria monocytogenes in the broth. Thus, this effect is typical and will not interfere with the functioning of the test. To be noted, turbidity can also arise from environmental bacteria growth. Therefore, the turbidity is not a sufficient indication of Listeria monocytogenes growth. Further, due to the test’s sensitivity, non- turbid tubes may be Listeria monocytogenes positives after 24h. Hence, only the N-Light™ reaction induced by the drop of the detection tablet can reliably indicate the presence of Listeria monocytogenes.
