The Technology Of Harmlessly Decontamination During Slaughter And Biological Preservative Of Chilled Chicken

As the outbreak of bird flu,Chilled chicken which is slaughtered and the carcass chilled rapidly to 0~4 ?,packaged,stored and transported at the same temperature is gradually replaced the live poultry and came into the consumer market.However,the serious microbial contamination in the slaughter and processing process and the lack of preservation technology in the storge period make safety problems and a short shelf life.This paper studies the technology of harmlessly decontamination during poultry slaughtering and the antibacterial and preservative technology during storage time.The experimental results are as follows:1.Using a certain concentration of lactic acid,trisodium phosphate,sodium pyrophosphate and chlorine dioxide to reduce the bacteria in broiler chicken before precolling.All of them can significantly reduce the number of microorganisms on the carcass(P<0.05).Among them,0.3% and 0.4% lactic acid have the better effect on killing microorganisms,and the number of microbial colonies on the surface of broilers could be reduced by 0.81 lg CFU/cm2.Four kinds of disinfectant can make the skin have higher L* value and a* value,lower b* value after 24 hours,but the lactic acid treatment group have higher b* value.Lactic acid and sodium phosphate treatment group show a smaller change of ?E value than the other two groups and control group(P<0.05).The sensory scores of two groups are both higher than 85.The 0.3% lactic acid has the best effect on precooling and sterilization.2.Before packaged,the surface of broiler was irradiated with 5 m W/cm2 of UV for 1~4 minutes to study the effect of sterilization and preservation.All treatments can reduce the total number of colonies.Among them,the 1 minute irradiation group and the control group had no significant difference(P>0.05),the total number of colonies of the rest groups are lower than those in the control group,and have significant difference(P<0.05),but the 4 minutes treatment group and the3 minutes treatment group have no significantly difference(P>0.05).UV radiation has no significant effect on L* value,a* value and b* value of the surface of broilers(P>0.05),and no significant change in color and odor in 4 minutes.The TBARS value of chicken skin increased with the extension of irradiation time,buthave no siginificant when the radiation time is less than 3 minutes(P>0.05).The 5.0 m W/cm2 intensity of short wave ultraviolet irradiation for 3minutes has best effect of sterilization,which can reducethe total number of colonies of 0.82 lg CFU/cm2.3.Determining the changes of microorganism,physical and chemical indexes and sensory evaluation of chilled chicken during 0~8 days storage time.During the storage period,the total number of colonies of chilled chicken is increasing.The number of gram positive bacteria was far less than those of gram negative bacteria.The average growth rate of gram negative bacteria was 0.50 lg CFU/cm2·d,The D-value with the total number of colonieswas less than 1.00 lg CFU/cm2.The trend of coliforms is consistent with the gram negative bacteria.The p H value of chilled chicken breast was increased from 5.70 to 6.20,and the TVB-N value andthe TBARS valuewere increased in the whole storage period.The change of POV value of chicken skin showed a trend of first increasing and then decreasing.The TVB-N value did not reach 15.00 mg/100 g after eight days of storage,while the TBARS value was over 0.50 mg/kg after 6 days of storage,and the POV maximum was 1.9 mmol/kg.The total number of colonies,TVB-N value,p H value,TBARS value and sensory score were significantly correlated,the correlation coefficient is greater than 0.9.4.Studying on the inhibition of various natural antimicrobial preservatives on four kinds of chicken common contaminating bacterias: Escherichia coli,Salmonella,Pseudomonas aeruginosa and Staphylococcus aureus,and optimizing the combination.The results showed that the concentration of N isin is 0.015%,the concentration of protamine is 0.60%,the concentration of chitosan oligosaccharide is 0.40%,the concentration of sodium lactate is 1.00%,and the addition of glycine is 0.20%.Preservative have good inhibitory effect on four kinds of tested bacterias.The antibacterial circle diameter for Escherichia coliis 11.14 mm,for Salmonella is 10.74 mm,for Pseudomonas aeruginosa is 11.52 mm,and Staphylococcus aureus is 16.58 mm.5.To choose natural coating preservation coating of chilled chicken,carboxymethylcellulosesodium,sodium alginate,oat beta-glucan,soybean protein and gelatinwere used.After compare the viscosity,light transmittance,oxygen permeability and theusageby microorganisms,the carboxymethylcellulosesodiumwas choosed asthe edible materials.Comparing the 0.40%?0.60%?0.80% carboxymethylcellulosesodium,the result show that 0.60% carboxymethylcellulosesodium has moderate viscosity,which is about 10.80 m Pa·s.Transmission rate in 500 nm is about 97%,and has a good oxygen barrier ability,TBARS values of sample are lower than the control group and the difference is significant(P<0.05).The material is not easy to be decomposed by microorganism.The water holding capacity is better than others.6.Broilers were pretreatment of lactic acid to reduce bacteria,combined with UV sterilization,and antibacterial coating preservative to determine the preservative effects.The total number of colonies are about 5.01 CFU/cm2 after 8 days,gram negative and gram positive bacteria are both decreased,the p H value is 6.01,TVB-N value is 11.85 mg/100 g,the TBARS value is 0.397 mg/kg,the sensory scores are still 60 points.GC-MS analysis turn out that the treatment have not a significant impact on the flavor of fresh chicken.Linear regression analysis turn out that the treatment will prolong the shelf life of chilled chicken to 10 days,while the shelf lifeof control group isjust 5 days.