Study On The Interference Of Trace Protein In Whey Products To The Detection Of Antibiotics

Whey powder is by-product of the cheese in the production process, it has great value,especially desalted whey powder, is widely used in infant formula. For the antibiotic testing of 10 different production batches of desalted whey powder,the results of national standard method I and Charm MRL ?-lactam rapid detection were all negative, but the results of Eclipse 50 And the national standard method II were parts of the negative and parts of the positive,that is the same sample with different detection methods will appear different results.In order to figure out the above-mentioned problems, we start from the antibiotic detection method, make comparative analysis of application and sensitivity in different detection methods. And then make the separation and extraction of trace protein which has positive result in antibiotic detection, in order to find out some components which may affect the detection result in whey powder. Simulation of whey production process and infant formula process in the laboratory environment, to identify the factor may affect the results in the production process.Finally, 10 different production batches of desalted whey powder were used as raw materials to ferment yoghourt, and then analyze the bacteriostatic effect of trace protein components in the desalted whey powder.In the comparison of the four detection methods, we found that Charm MRL-? lactam rapid detection has the shortest detection time and the strongest specificity; Eclipse 50 has short time and simple operation than the national standard method, and it has good controllability, is suitable for practical application in the rapid detection; The national standard method requires professionals in the laboratory environment, and is prone to errors by the misoperation.A series of experiments, such as dialysis, ultrafiltration and gel chromatography, found that the proteins with molecular weight above 100 KD could affect the detection of antibiotics which had positive results of antibiotic detection was isolated and extracted.When the whey production process was simulated in laboratory environment.The detection of antibiotic residues above whey, the results are non-antibiotics, it can proof that whey production process has no effect on the detection of antibiotics. The false-positive results were detected by the Eclipse 50. According to infant formula milk powder production process, adding different production batch of the D90 desalted whey powder to make the mixing concentrate, detection of antibiotic residues, found that do not contain antibiotics,it indicate that the protein affected the antibiotics detection has no effect on infant formula antibiotics detection.Finally,10 different production batches of desalted whey powder were used as raw materials to ferment yoghurt. It was found that micro-protein components inhibited the fermentation of reconstituted milk, and the inhibitory effect was obvious. Therefore, for the application of desalted whey powder, when use the desalted whey powder as raw materials to make of non-fermented food, can inhibit microbial growth to some extent, thereby extend the shelf-life; when use the desalted whey powder as raw material to make fermented food, the inhibition of trace protein will affect the production of the product in some degree, making it not suitable for fermentation food as raw materials.