Research On Rapid Detection Methods For Pork Freshness And Main Risk Factors

Pork,rich in protein,lipid and other nutrients,is delicious and a kind of essential edible meat in the world.However,pork is likely to be contaminated during the transport,storage,processing,marketing,etc.Biological risk factors,microbial contamination account the first,and chemical risk factors,heavy metal pollution occurs most frequently.In addition,freshness is one of the most important indicators for judging the edible value of pork,directly reflect the quality and safety of the products.The main factors that leading to the corruption of fresh pork are pollution and proliferation of microorganisms.Therefore,it is particularly necessary to detect the microorganisms and heavy metals of fresh pork,especially for on-site testing,which has substantial research significance.However,the traditional methods of detecting microorganisms and heavy metals are limited by many conditions,such as instruments,costs,testing time and personnel operations,which can not meet the needs of on-site testing,therefore,this study proposed and designed several rapid detection methods to meet the needs.This study based on the phenomenon that pork peroxidase in cells could catalyze tetramethylbenzidine(TMB)chromogenic reaction as well as analysis the total number of colonies in pork sample by the technique of real-time fluorescent quantitative PCR,developing a rapid test kit to detect the freshness of pork.The freshness of pork could be divided into five levels,which are fresh meat,medium fresh meat,less fresh meat,medium corruption meat and corruption meat,based on the relevance between meat freshness and color levels and the total number of colonies.The corresponding total number of colony forming units(CFU/g)range of five levels are(0,103),[103,104),[104,105),[105,106),more than 106.Through choosing five optimal levels,establish color and colony total standard ratio color card,the freshness of meat and the total number of colonies could be detected rapidly,directly,and semi-quantitative.This subject developed rapid test strip for three common heavy metals which are mercury,lead and copper,they are another common risk factors in pork.It can semi-quantitatively determine the heavy metal content,by the color change of the test paper and compare with the standard ratio color card,reduce the detection time greatly.The detection range of three test paper strips is respectively 0?200 ppm,0?500 ppm and 0-50 ppm.In addition,combined the original DNAzyme and aptamer,develop one DNAzyme-aptamer dual-function sensor,the simultaneous detection of microorganisms and heavy metals can be achieved.It is the first time that the simultaneous detection of different types of risk factors in pork.The detection range of gram-negative bacteria was 1?105 CFU/mL,and the detection limit was 1.0 CFU/mL.The detection range of Cu2+ is 1?103 ng/mL,and the detection limit is 1.0ng/mL.This sensor has been achieved with higher efficiency,better accuracy and innovation,high practicality,and more convenient for food safety testing on-site.