Prevalence of food contamination with Listeria spp. in Kermanshah, Islamic Republic of Iran

Abstract

Listeria monocytogenes is a human pathogen causing serious diseases. We aimed to determine food contamination with Listeria spp. in Kermanshah, Islamic Republic of Iran. Samples (185 dairy, 187 meat products and 158 ready-to-eat foods such as salads) were randomly collected from markets. After processing, samples were cultured in half-Fraser and Fraser broth followed by cultivation on PALCAM and Oxford media. Confirmatory tests including carbohydrate utilization were performed on isolates to determine species. Bacteria were isolated from 66/530 samples (12.5%). Meat products showed the highest (27.2%) and dairy products the lowest (3.8%) contamination rates. L. innocua was found in 56 (10.6%) samples, but L. monocytogenes was only found in 3 samples (0.6%). The results indicate that the rate of contamination with L. monocytogenes, even for ready-to-eat foods, was low but for other Listeria spp., in particular strains of L. innocua, the rate of contamination was higher, suggesting that more control on food sanitation is required. RÉSUMÉ Listeria monocytogenes est un agent pathogène humain à l'origine de maladies graves. Nous avons cherché à établir la prévalence de la contamination alimentaire par Listeria spp. à Kermanshah (République islamique d'Iran). Des échantillons (185 produits laitiers, 187 produits carnés et 158 plats prêts à consommer, comme des salades) ont été collectés au hasard sur les marchés. Après traitement, les échantillons ont été mis en culture dans un bouillon de Fraser-demi et de base Fraser puis repiqués sur gélose PALCAM et en milieu Oxford. Des tests de confirmation, y compris l'utilisation des glucides, ont été réalisés sur des isolats afin de déterminer l'espèce. Des bactéries ont été isolées dans 66 échantillons sur 530 (12,5 %). Les produits carnés étaient les plus fréquemment contaminés (27,2 %) tandis que les produits laitiers étaient les moins fréquemment contaminés (3,8 %). L. innocua a été identifiée dans 56 échantillons (10,6 %), alors que L. monocytogenes n'a été retrouvée que dans trois échantillons (0,6 %). Ces résultats indiquent que le taux de contamination par L. monocytogenes, même dans les plats prêts à consommer, était faible, mais que pour les autres Listeria spp., en particulier les souches de L. innocua, le taux de contamination était plus élevé, suggérant qu'un contrôle plus strict de l'hygiène alimentaire est requis.‫املتوسط‬ ‫لرشق‬ ‫الصحية‬ ‫املجلة‬ ‫عرش‬ ‫التاسع‬ ‫املجلد‬ ‫اخلامس‬ ‫العدد‬ 475

Isolation and Molecular Detection of Listeria monocytogenes in Minced Meat, Frozen Chicken and Cheese in Duhok Province, Kurdistan Region of Iraq

“…It should be noted that the contamination rate of Listeria in dairy products in our study was consistent with the results of [14]. A low level (1.1%) of L. monocytogenes contamination was found in soft cheese by [13]. Those results are different from the ones obtained in our study.…”

“…This could be due to preparing and processing minced meat (used, for example, in kebabs) in poor hygienic conditions Akya et al [13]. Although other factors such as equipment and food additives can also have a role in contamination, kebabs tend to be well cooked prior to consumption, reducing the chance of acquiring listeriosis in this kind of food Akya et al [13]. Our results showed differences when compared to other studies.…”

“…These results indicate that meat products are considerably more likely to be contaminated with L. monocytogenes than other food products. This could be due to preparing and processing minced meat (used, for example, in kebabs) in poor hygienic conditions Akya et al [13]. Although other factors such as equipment and food additives can also have a role in contamination, kebabs tend to be well cooked prior to consumption, reducing the chance of acquiring listeriosis in this kind of food Akya et al [13].…”

Isolation and Detection of Listeria monocytogenes in Minced Meat, Frozen Chicken and Cheese in Duhok Province, Kurdistan Region by using RT-PCR

“…It should be noted that the pathogenic L. monocytogenes in our research for the contamination rate of Listeria in dairy products, cheese are consistent with the results indicated by Jalali and his team [16]. A low level (1.1%) of L. monocytogenes contamination was found in soft cheese by Akya et al [15]. These results are not going with the current study.…”

“…The findings of these results indicated that the meat products were considerably more likely to be contaminated with L. monocytogenes than other food products. This could be due to the fact that preparation and processing of minced meat, like kebab, might be done in a poor hygienic condition [15]. Although other factors like equipments and food additives can also have a role in contamination, Kebab is well cooked before eating and thus reduces the chance of getting Listeriosis in this kind of food [15].…”