Detection of beta-lactamase in milk and milk products by iodometry

Abstract

The invention relates to a method for rapidly detecting beta-lactamase in milk and milk products. The fundamental principle is that: the beta-lactamase can decompose penicillin, and a decomposition product penicilloic acid competes with starch for free iodine to damage a composite formed by the iodine and the starch to further change blue solution into colorless solution; and the penicillin and an iodine-starch color reagent are added into the treated milk and the treated milk products, blank control is performed, and qualitative and semi-quantitative analysis is performed on the beta-lactamase according to the change of the color of the solution. In the invention, the novel method for detecting the beta-lactamase in the milk and the milk products is established in terms of the concentration of the penicillin, a pH value of buffer solution, the concentration and proportion of the color reagent, actual sample purification conditions, reaction temperature, centrifugation conditions and the like. In the method, the lowest qualitative and semi-quantitative detection limit is 1.5 U / mL. The technology is popularized, and a detection kit is researched and developed to realize real-time online detection, thereby bringing good social and economic benefits.

Description

technical field [0001] The invention belongs to the technical field of rapid detection, in particular to detecting β-lactamase added in milk and milk products by using a chemical method, i.e. iodometric method. Background technique [0002] As the country pays attention to food safety issues and some dairy companies have put forward the goal of no milk resistance in 2010, the problem of antibiotic residues has become one of the important factors affecting the safety of dairy products. Currently, penicillin, as a β-lactam drug, is the drug of choice for the treatment of bovine mastitis and is the most common residual antibiotic in milk. Because most domestic dairy companies adopt the principle of reducing the price of milk with excessive antibiotic residues, driven by economic interests, some illegal milk stations artificially use some biological agents to degrade the antibiotics remaining in milk in order to seek their own economic interests. Artificial "antibiotic-free mil...

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Problems solved by technology

[0003] At present, the detection techniques of β-lactamase in milk include cup and saucer method, iodometric method, acidity method, high performance liquid chromatography and enzyme-linked immunosorbent method, etc., but all of them have defects, such as poor specificity and repeatability, and large background interference , complex operation steps, not suitable for rapid screening of large batches of samples

Therefore, so far, the country has not issued corresponding testing methods and testing standards for this kind of artificial "anti-antibiotic milk", so it is impossible to monitor and control the quality of raw milk from the source

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