Study Of Comparison Of Detection Methods Of β-Lactamase In Dairy Products

β-lactamase is an ectoenzyme which is produced by β-lactam type of antibiotic resistant strains.β-lactamase can destroy the β-lactamse antibioti optionally, it makes penicillin lactam losing ofactivity by destroying its construction. With this property, β-lactamase is mixed into raw milk whichhas antibiotics by pushers, so that the antibiotic milk can reach the standard when in thedetermination of antibiotics. More and more attention of food safety came from the citizens, as theresult, determination of β-lactamase became a part of dairy determination, especially in thedetermination of raw milk. There are several methods for detectingβ-lactamase in dairy products.Cylinder Plate Method has good accuracy, but it requires a high quality equipment and lab.Iodometric method takes less time than Cylinder Plate Method, as well as it can be experienced inbasic facility lab, whereas its experimental reproducibility is poor. Even though rapid test kit isconvenient efficient, most of small milk stations and detection mechanism cannot afford it becauseof its high price. Therefore, this paper aimed at comparing every methods’ advantages anddisadvantages, which helps the inspectors to choose a suitable method.Since penicillin inhibits the growth of Micrococcus luteus, producing a zone of inhibition, thedifference between the diameters of inhibition zone produced by penicillin alone and together withsulbactam, which specifically inhibits the activity of β-lactamase, will indirectly suggest whether ornot a sample contains the enzyme.Iodometric method can make indirect judgement whether it has β-lactamase in the milk andmilk product with detectingthe decomposed product penicilloic acid which could reacted with iodine.The qualitative analysis of β-lactamase could be made by the color fading of the iodine solution inthe process of the direct iodometric method. In order to ensure the repeatability and accuracy, testwas centrifugal removing the fat of the sample. Then, it got a good accuracy and experimentalreproducibility, it prevented the phenomenon of false positives.Comparing three rapid test kits’ detection limit and the reaction time required. The accuracyand experimental reproducibility of kits were as good as Cylinder Plate Method. The crux ofdetection is that the time and temperature of reaction of samples and reagent. Investigation of products of small milk stations and some dairy factories indicated that the useof beta lactamase in dairy was less, currently.