Microbiological analysis of water and lettuce (Lactuca sativa) cultivated in hydroponic and aquaponic systems and in soil.

Resumo

The water from aquaculture is often enriched with nutrients, which provides potential for use in hydroponic production of vegetables such as lettuce. However, this vegetable can be a vehicle for transmitting diseases pathogenic to humans when contaminated. Currently there is a concern about the quality and the risks that food can bring, due to the high incidence of diseases transmitted by these products. In this sense, the objective of this work was to evaluate the sanitary conditions of water and vegetable cultivation in hydroponic and aquaponic systems. Were analyzed 10 samples of water from hydroponic cultivation and 10 samples from aquaponic cultivation, as well as 10 samples of each lettuce growing system, hydroponic, aquaponic and soil. The analysis were performed in duplicate for coliforms at 35ºC and 45°C, coagulase-positive staphylococci and Salmonella spp.. The results showed that both samples of the hydroponic and aquaponic systems presented 100% of coliforms contamination at 35ºC, and that 40% of samples from aquaponic and hydroponic systems presented 30% of Escherichia coli. In the evaluation of lettuce samples it was not detected the presence of Salmonella spp. and staphylococci positive coagulase. However all lettuce samples from aquaponic, hydroponic and soil cultivations showed coliforms at 35ºC (>3NMP/g) and only two samples from the hydroponic system showed coliform at 45°C. It was found that all the cropping systems evaluated in this study provided similar microbiological quality for the final product. So, one can conclude that the samples are suitable for human consumption.

DOI: http://dx.doi.org/10.14685/rebrapa.v2i2.46