The Construction Of Growth Prediction Model Of Specific Spoilage Organisms And The Study Of Changes In Freshness Parameters Of Paralichthys Olivaceus

The moisture content of aquatic is high, and the rich-nutrition, therefor they’reeasily putrefactive. The corruption of the aquatic is mainly caused by microbes, notall of the microorganisms are involved in corruption process.Those that grow andproduce corruption stink and peculiar smell on microbial metabolic products arecalled specific spoilage organisms.The detection of aquatic products on SSO isrelatively complex with a long cycle. However, microorganism forecast technologycan obtain the the number of SSO in aquatic products without experiment. Microbialgrowth medium and accurate mathematical model are the basese of effectivemicroorganism prediction model on the determination of SSO on aquatic products.Shewanella putrefaciens is the SSO of Paralichthys olivaceus during chilledstorage. It’s studied that the growth rule of Shewanella putrefaciens in liquid mediumin different temperatures, using Curve Expert software to fit Shewanella putrefaciensat different temperatures on Gompertz, logistic, Richards, MMF, Weibull model.Analyzed these five models and established second model the reliability of the modelwas validated. Fresh Paralichthys olivaceus fish is inoculated with Shewanellaputrefaciens. The fish meat is storied at0,5,8,10,15℃,determine the sensory, totalbacterial count, TVB-N, pH, the number of Shewanella putrefaciens during storage.Collected the number of Shewanella putrefaciens then establish five primary models.Analyze these five models and establish second model the reliability of the modelswas validated. The results are as follows:1. Using Curve Expert software to analyze, the data obtained fitted better with theShewanella putrefaciens growth curve by Gompertz model. Analysis showed that thecorrelation coefficients obtained are higher than0.99. The second model is descriptionby Belehradek. Temperature and μmax and Lag relations are：μmax=0.015× （T+16.1797）；1Lag=0.04183×（T+5.3006），R2respectively are0.9769、0.9588.Using Shewanella putrefaciens at8℃to verify,the bias factor and accuracyfactor are0.9916and1.0139,error is less than10%.It indicates that the model isreliable and effective.2. Inoculated Shewanella putrefaciens into Paralichthys olivaceus fish, store at0,5,10,15℃. Gompertz model can better fit with Shewanella growth curve. Thesecond model is described by Belehradek. Temperature and μmaxand Lag relationsare：μ max=0.014×（T+7.195）；1Lag=0.0189×（T+5.562），R2respectively are0.9910,0.9793.Using Shewanella putrefaciens at8℃to verify, the bias factor andaccuracy factor are0.9212and1.0908,error is less than10%indicates that model isreliable and effective.3. Determining fresh changes of Paralichthys olivaceus fish at0,5,8,10,15℃.When they reach the shelves by the senses, the valuesof TVB-N are34.82,31.16,33.22,32.96,30.64mg/100g，total bacterial count are6.81、7.07、7.06、7.31、7.26g（cfu/g）.