Listeria bacteria cause disease in offspring in animals as well as in humans. Among animals, sheep were found to be more susceptible to listeria disease than cattle. This bacterial disease especially affects the central nervous system of lambs. Listeria bacteria 1-2 are mixed with blood and produce toxins in lambs monthly. 4-8 causes inflammation in the brain in monthly lambs. After the clinical findings, 2-3 deaths occur at most days. Sometimes the sheep start to rise from anorexia and fever due to this disease and still have stillbirths.

The susceptibility of animals to listeria bacteria increases in sudden feed changes, in the introduction of new animals in the herd, in the transition period, when there are other bacterial diseases affecting the digestive systems.

Even if all the sheep in the herd are infected with listeria bacterial species, clinical signs of the disease appear in up to 10 of the herd due to natural resistance. Listeria disease occurs in animals, especially in winter. Because during this period, animals are given more silage (ie, stored in silos, containing high humidity and fermented animal feed).

In the laboratories, microbiological plantings are performed on animal feed samples and listeria spp. It is produced.

In the detection of Listeria bacteria species, rapid test methods are also used along with advanced test methods such as bacteriological culture or gram staining. In advanced laboratories, within the scope of microbiological analysis, listeria spp. analyzes are made. A few standards based on these studies are:

• TS EN ISO 11290-1 Microbiology of food and feedstuffs - Method for the detection and counting of Listeria monocytogenes - Part 1: Search method
• TS EN ISO 11290-2 Microbiology of food and animal feeds - Horizontal method for the detection and counting of Listeria monocytogenes - Part 2: Counting method