Microbiological evaluation and quality assessment of indoor air of food establishments from two universities in northern Portugal

Indoor air quality of 8 canteens and 12 cafes of two universities in northern Portugal were studied by evaluation of total mesophilic bacteria (TMB) and fungi throughout passive air sampling. Factors such as location, establishments' type, areas and the standard index of microbial air contamination (IMA) were investigated for determination of the indoor air quality. Total TMB and fungi counts were about 30 CFU/dm(2)/h and 85 CFU/m(3) respectively. By location, TMB counts differ only among cafes at same location (p<0.05). Fungi counts were, on average, higher in canteens than cafes. Most of food establishment analyzed displayed a good air quality according to the IMA (average IMA=15). The higher counts of TMB and fungi observed in canteens than cafes could be also influenced by presence of raw food products, high humidity or high temperatures due to cooking and preparation procedures which provide optimal conditions for mould growth, explaining the higher counts in kitchen, raw food areas or preparing areas. The indoor air quality in canteens and cafes for TMB and fungi were acceptable and not represented a public health concern for students. The results of the present work could be used to improve the indoor air quality of food establishment at universities.