Staphylococcus aureus(S.aureus)is one of the main pathogens in dairy and meat products,hence there is a need to develop high-sensitive and rapid method for its detection.In this paper,a quantitative detection of S.aureus was developed by employing silica-coated magnetic nanoparticles(Si-MNPs)and thermophilic helicase-dependent isothermal amplification(tHDA).Firstly,genomic DNA from lysed bacteria was extracted by Si-MNPs and amplified by tHDA.After adding nucleic acid dye SYBR Green I into the amplicons,fluorescence intensity was recorded by fluorescence spectrophotometer.This detection system provided a detection limit of 5×100 cfu/mL in pure culture and milk powder sample,and 5×101 cfu/mL in pork sample using ultraviolet lamp in less than 2 h.In addition,under optimal conditions,a good linear relationship was obtained between the fluorescence intensity and bacteria concentrations ranging from 102 to 104 cfu/mL.Furthermore,the results from contaminated milk powder and pork samples indicated that the detection system can be used for the quantitative analysis of S.aureus and can be potentially applied in the food industry for detection of this pathogen.