Isolation of Listeria monocytogenes recovered from some ready-to-eat foods sold in Kano, north-western Nigeria
Listeria monocytogenes and other Listeria species were isolated from some ready-to-eat foods sold in Kano metropolis. The method of United States Food and Drug Administration, Center for Food Safety and Applied Nutrition (FDACFSAN) was adopted in the isolation of the organism. A total of 336 food samples were screened. This included 29 beef burger, 30 yoghurt, 32 locally fermented fresh milk (nono), 34 cabbage, 45 grilled meat (tsire), 48 lettuce, 55 meat-pie and 63 roasted meat (balangu) samples. Samples were collected from December 2012 to March 2013. From these samples 38 (11.3%) yielded Listeria species. Six isolates (1.8%) were found to be L. monocytogenes, 31 (9.2%) were found to be L. ivanovii and 1(0.3%) was L. seeligeri. Out of the 38 isolates, 7 (18%) were from ‘balangu’, 9 (24%) cabbage, 14 (37%) lettuce, 5 (13%) meat pie and 3 (8%) ‘tsire’ samples. L. monocytogenes was isolated from 3 lettuce samples (50%), 2 ‘balangu’ samples (33%) and 1 meat-pie sample (17%). On the other hand, L. monocytogenes was not isolated from ‘tsire’, beef burger, ‘nono’ and yoghourt samples. This study showed the presence of the organism in Kano, which could pose a threat of outbreak or sporadic cases of listeriosis with high morbidity and mortality rates.
Keywords: Isolation, Listeria monocytogenes, Ready-to-eat foods, Kano.