| This study focused on the spoilage of cooked meat products caused by microorganism in meat industry. The spoilage microorganisms were isolated and identified, and the effective, heat stable, cheap compound preservatives were developed. The antimicrobial effect of natural spice essential oils was also researched, it mainly provided theoretical basis for antiseptic policy in meat industry.Contaminated microorganisms were isolated from vacuum-packaged cooked meat products, such as ham, spicy pork, sauced pork liver and pickled pepper chicken claw in main meat producing area in China, and were identified by the method of 16S rDNA analysis. Microorganisms isolated from septic ham contained Paenibacillus polymyxa, Acinetobacter johnsonii, Hafnia alvei, Staphylococcus saprophyticus, Kurthia gibsonii, Erwinia amylovora, Bacillus circulans, Bacillus subtilis, Bacillus licheniformis, Bacillus coagulans and Enterococcus casseliflavus. Leuconostoc mesenteroides was isolated from septic spicy pork, Enterococcus sanquinicola, Proteus vulgaris and Swine manure bacterium were isolated from spoiled sauced pork liver, and Oceanobacillus oncorhynchi was separated from spoiled pickled pepper chicken claw. Leuconostoc mesenteroides, Enterococcus sanquinicola, Proteus vulgaris, Swine manure bacterium, Kurthia gibsonii, Hafnia alvei and Enterococcus casseliflavus belonged to enterobacteria in these contaminated microorganisms. Bacillus subtilis, Bacillus circulans, Bacillus licheniformis and Bacillus coagulans may be derived from fod probiotics, or from the environment. Contaminated microorganisms Bacillus subtilis, Staphylococcus saprophyticus and Paenibacillus polymyxa may directly come from enviroment. The analysis of contaminated microorganisms is benefit to take measures to prevent meat products spoilage.The minimum inhibitory concentration of different preservatives was tested by disc diffusion and turbidimetric method, results showed that r.-polylysine, Nisin, disodium EDTA and preservative A possessed high antimicrobial effect.ε-polylysine had high antimicrobial effect for Leuconostoc mesenteroides, Bacillus subtilis, Enterococcus sanquinicola, Bacillus pumilus, Bacillus thuringiensis, Oceanobacillus oncorhynchi and Hafnia alvei, its minimum inhibitory concentration for these microorganisms were 0.08 mg/ml,0.04mg/ml,0.2 mg/ml,0.2 mg/ml,0.4 mg/ml,0.02 mg/ml,0.2 mg/ml, respectively. Nisin had high antimicrobial effect for Leuconostoc mesenteroides, Bacillus pumilus, Bacillus subtilis, Enterococcus sanquinicola, Oceanobacillus oncorhynchi and Hafnia alvei, its minimum inhibitory concentration for these microorganisms were 0.1 mg/ml,0.06 mg/ml,0.2mg/ml,0.1 mg/ml,0.2 mg/ml,0.4 mg/ml, respectively. Disodium EDTA had high antimicrobial effect for Leuconostoc mesenteroides, Bacillus pumilus, Bacillus subtilis, Bacillus thuringiensis, Swine manure bacterium, Oceanobacillus oncorhynchi and Hafnia alvei, its minimum inhibitory concentration for these microorganisms were 0.4 mg/ml,0.08 mg/ml,0.08 mg/ml,0.2 mg/ml,0.4 mg/ml,0.1 mg/ml,0.08 mg/ml, respectively. Preservative A had high antimicrobial effect for Leuconostoc mesenteroides, Bacillus pumilus, Bacillus subtilis, Bacillus thuringiensis, Enterococcus sanquinicola, Proteus vulgaris, Swine manure bacterium, Oceanobacillus oncorhynchi and Hafnia alvei, its minimum inhibitory concentration for these microorganisms were 0.1 mg /ml,0.2 mg/ml,0.4 mg/ml,0.2 mg/ml,0.2 mg/ml,0.2 mg/ml,0.2 mg/ml,0.06 mg/ml,0.1 mg/m, respectively. Sodium diacetate played partial antimicrobial effect for some microorganisms, but in general, its antimicrobial effect was lower than the antimicrobial effect ofε-polylysine, Nisin, disodium EDTA and preservative A. Potassium sorbate, sodium benzoate and sodium dehydroacetate played partial antimicrobial effect for separated microorganisms, but could not inhibit microbial growth completely.According to the minimum inhibitory concentration of different preservatives for separated microorgamisms, the antimicrobial effect of compound preservatives were studied. And we obtained the compound preservative formula that played high antimicrobial effect for four strains isolated from meat products made in the same plant, respectively. The optimal compound preservative formula for Leuconostoc mesenteroides was Nisin:0 mg/ml, preservative B:0.06 mg/ml,ε-polylysine:0.06 mg/ml, preservative A:0 mg/ml. The formulae of compound preservative that have high antimicrobial effect simultaneously for four strains were obtained, they were①sodium diacetate:0.5 mg/ml, disodium EDTA: 0mg/mL preservative B:0.1 mg/ml, preservative A:0.15mg/ml, Nisin:0 mg/ml,②sodium diacetate: 0.75mg/ml, disodium EDTA:0.063 mg/ml, preservative B:0.1 mg/ml, preservative A:0.1 mg/ml, Nisin:0.075mg/ml, respectively. Results indicated that compound preservatives developed in this study had high inhibition effect for tested strains.Antimicrobial effect of twenty essential oils was also studied by disc diffusion and 96 well microtiter plate method, in order to comprehend their inhibition effect for contaminated microorganisms in meat products. According to the assay of minimum inhibitory concentration of various essential oils for nine tested strains, results showed that antimicrobial effect of Clove bud essential oil and Cinnamon oil was high. The minimum inhibitory concentration of Clove bud essential oil for Leuconostoc mesenteroides, Enterococcus sanquinicola, Proteus vulgaris, Swine manure bacterium, Oceanobacillus oncorhynchi, Hafnia alvei, Staphylococcus saprophyticus, Kurthia gibsonii and Erwinia amylovora was 8/10000μl/μl,2/1000μl/μl,8/10000μl/μl,8/10000μl/μl,4/10000μl/μl,8/10000μl/μl,6/10000μl/μl,8/10000μl/μl and 4/1000μl/μl, respectively. The minimum inhibitory concentration of Cinnamon oil for Leuconostoc mesenteroides, Proteus vulgaris, Swine manure bacterium, Oceanobacillus oncorhynchi, Hafnia alvei, Staphylococcus saprophyticus, Kurthia gibsonii and Erwinia amylovora was 1/1000μl/μl,4/10000μl/μl,4/10000μl/μl,1/10000μl/μl,4/10000μl/μl,2/10000μl/μl,2/10000μl/μl and 4/10000μl/μl, respectively. Antimicrobial results in this experiment showed that antimicrobial effect of Clove bud essential oil and Cinnamon oil for other eight strains was high, except Enterococcus sanquinicola. Furthermore, most of essential oils had high antimicrobial effect for Oceanobacillus oncorhynchi. |
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