PRESENCE OF LEGIONELLA PNEUMOPHILA IN EVAPORATIVE CONDENSERS AND ITS RELATION WITH THE CHARACTERISTICS OF THE WATER
Legionella is a microorganism widely spread in the aquatic environment, from where it may reach the supplying and distribution network of public water and, eventually, the refrigeration systems of industrial facilities and buildings. Particularly, the evaporative condensers are cooling devices that spread aerosols to the air, susceptible of containing Legionella. In these equipments several factors that favour the development and dispersion of this microorganism take place.Therefore, evaporative condensers placed in refrigeration systems of food factories were characterized and sampled during a 5 month period. The most relevant physical and chemical characteristics of waters used in these evaporative condensers were determined. Besides, the presence of amoebae and other protozoans was analyzed, the number of mesophilic aerobic microorganisms was determined, and the presence of Legionella spp. was studied.The physical and chemical characteristics of the water exceeded the recommended levels in many cases, showing that the water of the evaporative condensers had a poor quality. These poor characteristics make these facilities of high risk regarding colonization by Legionella spp. They also may hamper the effectiveness of disinfection and may lead to the deterioration of the equipment.Most of the sampled facilities showed presence of amoeba and other protozoa, algae such as diatoms, as well as biofilm formation in the internal surfaces of condensers. The growth of these microorganisms is increased by sun light and dirtiness coming from the exterior of these condensers. Mesophilic aerobic microorganism counts were high in most of the samples, including those taken shortly after cleaning the equipment. These high counts indicate that the methods of disinfection used are not efficient and suggests that a re-evaluation of these methods as well as of the maintenance of the equipments should be carried out.The analysis showed Legionella pneumophila presence in some of the evaporative condensers, in spite that all the facilities were exposed to a preventive treatment of cleaning and disinfection. The results also showed that high counts of microorganisms are not always linked to Legionella presence.
A.CASTA(N)O E.HERN(A)NDEZ A.L(O)PEZ A.PALOP
Dept. Ing. Alimentos y Equipamiento Agrícola – UPCT, Paseo Alfonso Ⅷ 48 Cartagena, 30203, Spain
国际会议
The 22nd International Congress of Refrigeration(第22届国际制冷大会)
北京
英文
2007-08-21（万方平台首次上网日期，不代表论文的发表时间）