Disinfectant effect of Methylated Ethanol against Listeria species 1

This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol) as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2) raw milk samples from different lactating cows within Sokoto metropolis (Nigeria). 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The samples were analyzed using selective culture and isolation technique in which the 288 samples collected before disinfection, 114 (39.6%) were positive for Listeria species. Among the positive samples 44 (38.6%) were Listeria innocua, 16 (14.0%) Listeria ivanovii, 36 (31.6%) Listeria monocytogenes, 11 (9.6%) Listeria welshimeri and 7 (6.1%) Listeria seeligeri, while none of the 288 samples collected after disinfection was positive. The study has shown high prevalence of Listeria species in milk collected without washing/disinfecting the teats and has also established the sensitivity of Listeria species to methylated ethanol which can be used as dip for disinfecting udder teats before milking in order to prevent contamination with Listeria species and other methylated spirit-sensitive organisms. This study is essential to educate Fulani herdsmen and other milk handlers on the importance of disinfecting udder teats before milking.


Introduction
which Listeria monocytogenes serotype 4b strains are responsible for 33 to 50 percent of Listeria monocytogenes is the major cause sporadic human cases worldwide and for all of listeriosis in both man and animals (Jemmi and major food borne outbreaks in Europe and North Stephan, 2006).The organism has cosmopolitan America since the 1980s (Ward et al., 2004).distribution in the environment and within the gut Listeriosis is usually a serious problem in of animals worldwide (OIE, 2005) and unsanitary immunocompromised individuals such as practices during slaughtering and milking processes pregnant women, infants, geriatrics, HIV or are the main causes of Listeria contamination AIDS patients, etc (Acha and Szyfres, 2003).(Schchat et al., 1991).Products such as raw milk, Pregnant women may experience abortion, raw meat products and vegetables are often stillbirth, premature birth and septicemia in the contaminated with the organism and serve as newborn (Acha and Szyfres, 2003).In the elderly, vehicles of transmission (Johansson et al., 1999).
L. monocytogenes causes meningitis, Other Listeria species include Listeria meningoencephalitis or, less frequently, ivanovii, Listeria innocua, Listeria welshimeri, septicaemia (Acha and Szyfres, 2003) 91-93, doi: 10.5455/vetworld.2012.91-93 1996).Methylated spirit® (95% methanol and analyze for any significant difference in the 5% ethanol) was chosen for trial in this study occurrence of the organisms in milk samples owing to its availability, accessibility and affordability collected before disinfection and in samples to both urban and rural dwellers in Nigeria.
collected after disinfection.

Materials and Methods Results
Study design and sample collection : A cross-Out of the 288 samples collected before sectional study was conducted within Sokoto disinfecting the udder teats, 114 (39.6%) were metropolis (Nigeria) and a total of 288 samples in positive for Listeria species and none of the duplicates (two each from an animal) were corresponding samples collected after disinfection collected from lactating cows in farms and Fulani was positive.Upon characterization of the isolates herds.The first 288 samples were collected from the positive samples 44 (38.6%) were before disinfecting the udder teats with Listeria innocua, 16 (14.0%)Listeria ivanovii, 36 Methylated spirit® while the other 288 were (31.6%)Listeria monocytogenes, 11 (9.6%) collected after disinfecting the teats with Listeria welshimeri and 7 (6.1%)Listeria seeligeri.Methylated spirit®.A minimum of 30ml each of The most common isolates were Listeria innocua the samples was collected in a sterile capped glass while the least isolates were Listeria seeligeri.bottles and were conveyed in an ice-packed Statistical analysis showed significant container to the Public Health Laboratory of the difference in the occurrence of the organisms in Usmanu Danfodiyo University Sokoto, Nigeria.
milk samples collected before disinfection and in samples collected after disinfection ( Culture and identification : Using culture and identification method as recommended by the = 139.65,p < 0.05).International Organization for Standardization Discussion (ISO 11290-1, 1996), 25ml of each sample was The study showed that Listeria species enriched using 225ml of ONE Broth-Listeria particularly Listeria monocytogenes, which is of (Oxoid CM1066 & SR0234) and incubated o public health concern could be found in raw milk aerobically at 30 C for 48 hours.The brothon sale within Sokoto metropolis.The presence enriched sample was inoculated onto Oxoid of these organisms in raw milk may be as a result Brilliance Listeria selective differential media of contamination from the udder teat during (Oxoid SR0227 and SR0228); 0.1ml of the broth o milking.More so, the organisms have not been was plated and incubated aerobically at 37 C for isolated from samples collected after disinfection, 24hours.Blue-green colonies on the media that which suggests that Listeria species are susceptible expressed gram positive coccobacilli on gram to Methylated spirit® and can therefore be used staining were presumed to be Listeria species.
as an effective teat disinfectant before milking.Biochemical Differentiation: Biochemical The prevalence of Listeria monocytogenes in this characterization using catalase, xylose, rhamnose study is 31.6%,which is higher than the findings and CAMP tests were further carried out in order of Emek et al. (2011) 116,190-193. 4. ISO 11290-1 (1996).Microbiology of food and without disinfection and its absence in samples animal feeding stuffs-Horizontal method of collected after disinfection suggests that the on the quality of milk collected when used as a 7. Salamina, G., Dalle-Donna, E., Niccolini, A., Poda, disinfectant. G., Cesaroni, D., Bucci, M., Fini, R.,Maldini, M., Schuchat, A., Swaminathan, B., Bibb, W., detection and enumeration of Listeria organisms are sensitive to Methylated spirit®.monocytogenes, Part I: Detection method.Moreover, the study shows that Listeria organisms 5. Jemmi, J. and Stephan, R. (2006).Listeria could be present in raw milk on sale within monocytogenes: food-borne pathogen and Sokoto metropolis, which is of public health hygiene indicator.Review Science and concern as it poses a serious threat to the health of Technology, office Intenational Epizootics. the populace.There is therefore the need for 25(2): 571-580.extensionpersonnel to educate the Fulani and 6.Johansson, T.,Rantala, L., Palmu, L. and   Honkanen-Bulzalski, T. (1999).Occurrence and other milk handlers the significance of good typing of Listeria monocytogenes strains in retail hygiene such as hand washing and disinfecting vaccum-packed fish products and in a udder teats before milking.There is also the need production plant.International Journal of Food to explore the possible effect of methylated spiritMicrobiogy,