Study On Evaluation Method For Preservatives Of Chilled Pork Based On The Inhibition Of The Growth Of Pseudomonas

The chilled pork has been the mainstream of pork products in account of itssafety, rich nutrition ingredients and good flavor. However, eliminating thecontamination of microorganism incompletely, it had a short shelf life. As the primarymethod of inhibiting the spoilage microorganisms, preservatives played a significantrole in extending the shelf of chilled pork. With regard to the present stage, theantibacterial function were evaluated by predicting modeling of shelf life throughconsidering the organoleptic characteristics, colonies number, pH and the total volatilebasic nitrogen (TVBN) synthetically, which needed large amount of work and canlimit the screening of preservatives. In this paper, the evaluation method ofpreservatives was explored by estimating the inhibition on Pseudomonas which is themajor spoilage organisms in chilled pork.This paper analyzed the chilled pork microorganisms by selective media, furtherIdentified that Pseudomonas were the dominating bacteria for microorganismsspoilage in cold fresh pork. the strains isolated from and purified from Pseudomonasselective plate, were identified as Pseudomonas fragi through the characteristics ofcolony，physiological，biochemical reactions, the molecular biological. Studied theability of antimicrobial60kinds of preservatives on the Fliter system, the resultsshowed that different preservatives had significantly different antimicrobial, there are18kinds of preservatives which had inhibition zone longer than13mm showed strongantibacterial effect,8kinds of preservatives showed weak inhibitory effect, which hada inhibition smaller than13mm,34kinds of preservatives did not have inhibition zoneshowed no significantly antibacterial ability.Antibacterial differences based on Filter system,30preservatives contain18kinds which has antimicrobial properties and12no significant inhibitory propertieswere selected for the Pseudomonas inhibition of liquid medium and pork medium.The results showed that in lipid medium20kinds preservatives under1g/L hadstronger inhibitory effect,10kinds preservatives did not show significanttyantimicrobial ability. The preservatives Which showed a strong inhibitory ability inlipid medium had a lager inhibition zone on Filter system.The growth ofPseudomonas on the pork medium under different preservative conditions weredescribed by the Gompertz growth model.the lag phase(LPD) can reflect thepreservative’s antibacterial, there are11kinds preservatives increased the LPD ofPseudomonas significantly increased,the others did not significantly affect the LPD of Pseudomonas. The preservatives which can increased the Pseudomonas LPD belongsto the preservatives which conducted strong antibacterials in Filter system or lipidculture.The growth parameters (U)showed that17kinds of preservatives decreasedthe Pseudomonas parameters (U),the others were not. The evaluation of antibacterialresults from these three different system,the preservatives of strong Pseudomonasinhibition in pork showed significantly antibacterial in Filter system and liquidsystem.By considering the total volatile basic nitrogen (TVBN), aerobic bacterial countand the organoleptic characteristics synthetically, the influence of30preservatives onextending the shelf life of cold fresh pork were studied. There are14of30preservatives can effectively extend the shelf life of chilled pork over2days, whichcontained11kinds of preservatives shown effective antibacterial in Flitersystem,liquid systems and pork systems. Meanwhile, the preliminary study on thechange of the cell morphology, alkaline phosphatase and electric conductivity causingby preservatives demonstrated that the inhibition was mainly achieved by changingthe morphology and intracellular environment of Pseudomonas which will disturb thecells.Based on this study, it preliminarily showed that the addition of preservativesunder different systems had a positive correlation with its inhibition, and that theinhibition of preservatives also had a positive correlation with the shelf life of chilledpork, which offered a new mentality to evaluate the preservation effect ofpreservatives on chilled pork. Thus, an effective new method for rapid assessment andselection of preservatives is hopefully formed to provide theoretical and practicalfoundation of building a system for controlling the quality of chilled pork throughfurther research.