Surface and equipment contamination with Listeria monocytogenes in slaughterhouses | Kontaminacija klaničnih površina i opreme sa Listeria monocytogenes

Listeriosis is an infective disease of many animals and humans (zoonosis). Clinically it is manifested in various forms, mostly as abortion and meningitis. The cause is Listeria monocytognes. It is an ubiquitar bacteri, found in over than 40 mammals, 20 bird species, several fish species and insects. After infection, clinical symptoms are sometimes not diagnosed and the animals arrive in slaughterhouse as healthy animals (unapparent infection). When animals, in this case goats, arrive for slaughter, the cause of the disease can be transmitted on the equipment and possibly on meat. In our examination, immediately after slaughter of clinically healthy goats, 20 swabs were taken from the bottom of trolleys for placing of the organs, 5 swabs from knives (between glade and grip) and 20 swabs from the floor. Three days after slaughter, 10 swabs were taken again from floor (from ten different places) and from the bottom of trollies (20 swabs) where the intestine and uterus were placed. The swabs were incubated in selective, enriched broth refrigerated at 5-8 deg C. On the third and seventh day they were inoculated on blood agar (5% sheep blood), Columbia (Himedia) and MacConkey agar (Biomedics) and incubated under the temperature of 37 deg C for 24-48 hours. the suspect colonies from blood and Columbia agar were controlled microscopically and, because of getting pure culture, re-cultivated on the same media. For examination of biochemical activity, commercial tests were used. For the identification BBL Crystal G/P ID kit was used. Listeria monocytogenes was isolated from two floor swabs, one knife swab and from two swabs from trollies. Except the one from floor, each isolate of Listeria monocytogenes was isolated from the broth inoculated for seven days. Listeria monocytogenes was isolated from two floor swabs three days after slaughter. These isolates were isolated from the broth inoculated for seven days. Our finding shows the possibility of indirect transmission of Listeria monocytogenes on meat.