The invention provides a method used for simultaneous detection of three food-borne
pathogenic bacteria based on multicolor upconversion
fluorescence labeling. According to the method, three upconversion materials with differentiable
fluorescence spectrums are used for forming multicolor upconversion fluorescent nanoprobes via respective connection with aptamers of
staphylococcus aureus,
vibrio parahaemolyticus, and
salmonella, and complementary
oligonucleotide single chains of the aptamers are connected with
magnetic nanoparticles so as to form nano-composites. When
bacteria to be tested are in a detection
system,
double chain unwinding is realized because of specific binding of the
pathogenic bacteria with corresponding aptamers; it is possible to realize simultaneous
quantitative determination of
staphylococcus aureus,
vibrio parahaemolyticus, and
salmonella by monitoring upconversion
fluorescence signal strength at 477nm, 550nm, and 660nm, detection
linear range ranges from 50 to 1000000cfu / ml, and detection limits are 25cfu / ml, 10cfu / ml, and 15cfu / ml respectively. The method is used for detection of
pathogenic bacteria, is high in sensitivity, is rapid and convenient, and can be used for detection of the three pathogenic
bacteria in food such as milk and
shrimp meat; and results are accurate and reliable.