Increased levels of markers of microbial exposure in homes with indoor storage of organic household waste

As part of environmental management policies in Europe, separate collection of organic household waste and nonorganic household waste has become incre asingly common. As waste is often stored indoors, this policy might increas e microbial exposure in the home environment. In this study we evaluated th e association between indoor storage of organic waste and levels of microbi al agents in house dust. The levels of bacterial endotoxins, mold beta(1--> 3)-glucans, and fungal extracullar polysaccharides (EPS) of Aspergillus and Penicillium species were determined in house dust extracts as markers of m icrobial exposure. House dust samples were collected in 99 homes in The Net herlands selected on the basis of whether separated organic waste was prese nt in the house. In homes in which separated organic waste was stored indoo rs for 1 week or more the levels of endotoxin, EPS, and glucan were 3.2-, 7 .6-, and 4.6-fold higher, respectively (all P < 0.05), on both living room and kitchen floors than the levels in homes in which only nonorganic residu al waste was stored indoors, Increased levels of endotoxin and EPS were obs erved, 2.6- and 2.1-fold (P < 0.1). respectively, when separated organic wa ste was stored indoors for 1 week or less, whereas storage of nonseparated waste indoors had no effect on microbial agent levels (P > 0.2). The presen ce of textile floor covering was another major determinant of microbial lev els (P < 0.05). Our results indicate that increased microbial contaminant l evels in homes are associated with indoor storage of separated organic wast e. These increased levels might increase the risk of bioaerosol-related res piratory symptoms in susceptible people.