The aim of this study was to investigate the microbiological quality of milk-shaked drinks including Bacillus cereus Escherichia coli Salmonella spp. Staphylococcus aureus yeast and molds in unsealed containers sold in market fair roadside and stall around Mahasarakham university. The analytical results revealed that microbiological quality of 30 samples of milk-shaked drinks in unsealed containers that did not pass the criteria of department of medicine ministry of public health Thailand were 50 % of total samples. Bacteriological counts of Bacillus cereus Escherichia coli Salmonella spp. And Staphylococcus aureus of milk-based drinks that did not pass the criteria were 13.3 10 13.3 and 10% of total samples respectively. Yeasts and molds counts of milk-based drinks that did not pass the criteria were 3.3 and 30% of total samples respectively. Microbiological contamination of milk-shaked drinks was related to the hygiene of the shop and the supplier. It was found that the location of stall which high dust particles and animal carriers also contributed to the contamination of microorganisms. Moreover the hygiene of the supplier may cause the milk-shaked drinks to be contaminated with microorganisms.

Using of ethylenediaminetetraacetic acid (EDTA) and synthetic surfactant increase the chemical contamination in water. The co-phytotoxicity of EDTA (0-20 mg/l) and 3 synthetic surfactants; Triton X-100 (0-10xCMC) Tween 80 (0-10xCMC) and sodium dodecyl sulfate (SDS) (0-2 x CMC) on the growth of 2 duckweeds spirodela polyrrhiza and Lemma perpusilla were studied for 3 days. The results showed that the surfactant were phytotoxic on the growth of both plants while EDTA was not. SDS was the most toxic to plant especially on all chlorophyll content. Triton X-100 was only toxic to the growth of L. perpusilla and weight of S. polyrrhiza. Tween 80 was less or the least toxic to both plants. This surfactant only decreased chlorophyll a and total chlorophyll content of S.polyrrhiza and L. perpusilla. There was not any interaction between EDTA and surfactant on most toxicity tests. With these results synthetic surfactant contamination should be more concerned than co-contamination with EDTA.