Studies On The Determination Of Chloramphenicol Residues In The Aquatic Foods By Luminescent Bacteria

Considering the low detection limit of Chloramphenicol (CAP) in aquatic foods and highly sensitive of luminescent bacteria to environmental pollution, the establishment of a rapid, sensitive, low-cost method for the detection of chloramphenicol is necessary.This paper established a quick method to determine the trace chloramphenicol in aquatic foods. Then do some research on the mechanism of Chloramphenicol on luminescence.1. Several luminescent bacteria strains were separated from the coast of Qingdao. Then selected a strain Photobacterium leiognathi YL which is sensitive to chloramphenicol. To optimize the luminous condition, results are: the optimum temperature is 25-30℃; flask speed is of 150 r / m; initial pH is of 7.5;the concentration of sodium chloride is 3-5%; the concentration of glycerin is 0.4%. Then do some research on the chemotaxis of P.leiognathi YL, obtained the conclusion: P.leiognathi YL is especially sensitive to chloramphenicol.2. System construction : A rapid cultivation of single colony was adopted to produce a type of luminescent bacteria suspension suitable for detecting CAP in seafood. Experiments indicated that the optimum interaction time was approximately 30 minutes,the initial luminescence of P.leiognathi YL was 3.0×105,the optimum volume ratio of the bacteria suspension to the CAP solution was 1:1 for their interactions.Under the system conditions , the inhibiting effects of CAP on luminescent bacteria presented good linear relationship,the liner range was from 0.1 ng/mL to 1.0 ng/mL with R2 of 0.989. The sensitivity of this system in detecting trace CAP can reach 0.1ng/mL. The system can be used as a rapid and convenient screen method for detecting CAP in seafood. The average recoveries were 40.34% to 114.26% when samples were spiked with 0.1ng/g to 1.0ng/g. 3. Some research was done on the mechanism of chloramphenicol on luminescence The results are: Trace chloramphenicol (below 1.0 ng/mL) influenced the luminous intensity instead of growth in the short-time impact(30min).