Table 1. List of indicator strains

	Strains	Collection no.	Culture media	Antibiotics resistant1)
Gram+	Staphylococcus aureus	KCCM 11335	TSB	-
	Staphylococcus aureus 285	CCARM 0204	TSB	Amp, Nor, GM
	Staphylococcus aureus 503	CCARM 0205	TSB	Amp, Nor, GM
Gram-	Escherichia coli	KCTC 2571	LB	-
	Escherichia coli 078	CCARM 0230	LB	Amp, Nor, GM
	Escherichia coli DC 0	CCARM 0237	LB	Amp, Nor, GM
	Escherichia coli 1507	CCARM 0236	LB	Amp, Nor, GM

AMP; ampicillin, Nor; norfloxacin, GM; gentamycin.