| In this paper, duck breast meat was used as test material to study the bacteria reduction process in duck breast shashlik processing environment and parameters of hurdle technology in the steps such as thawing and salting, and optimal process parameters for reducing bacteria have been obtained. The effects of different sterilization methods on sensort quality and shelf life were also studied. Main findings were as follows:1. The air in each workshop was disinfected by 100 mg/L steady state ClO2 spray, and changes of total number of colonies in the workshop was detected before and after the disinfection. Total number of colonies in the air in the thawing workshop, processing workshop, stewing workshop and the packing workshop has been reduced by 3.2×103 cfu/cm3,1.8×103 cfu/cm3,5.1×103 cfu/cm3,0.4×103 cfu/cm3, respectively. Product processing of related steps in each workshop disinfected with steady state ClO2 can also directly reduce the total number of colonies in duck breast shashliks in each step. Compared with the controls, total number of colonies in duck breast shashliks was reduced from 8.1×105 cfu/g to 3.8×105 cfu/g after penetrated by bamboo sticks in the thawing workshop, from 1.5×103 cfu/g to 0.5×103 cfu/g after cutting bamboo sticks in the processing workshop, from 2.6×103 cfu/g to 1.1 ×103 cfu/g after stewing, and from 2.1×103 cfu/g to 1.2×105 cfu/g after vacuum-packaging.2. Effects of ozone water and steady state ClO2 on bacterial reduction were studied during duck breast meat thawing process. The results showed that the optimal parameters for bacterial reduction when thawing by immersing in ozone water were: thawing temperature of 10℃, ratio between meat and solution of 14:100 （m:V）, ozone water concentration of 7.7 mg/L and thawing duration of about 40min. Compared with the controls, the total number of colonies in the duck breast meat was reduced from 2.7×105 cfu/g to 1.1 ×103 cfu/g, the number of coliform group reduced from 1500 MPN/100g to 90 MPN/100g, and the value of color difference increased by 1.07. The optimal parameters for bacterial reduction when thawing by immersing in ClO2 solution were:thawing temperature of 20℃, ratio between meat and solution of 15:100 （m:V）, steady state ClO2 concentration of 7.7 mg/L and thawing duration of about 40 min. Compared with the controls, the total number of colonies in thawed duck breast meat was reduced from 2.7×1O5 cfu/g to 7.1×103 cfu /g, the number of coliform group reduced from 1500 MPN/100g to 110 MPN/100g, and the value of color difference increased by 0.14. After comparative analysis, it was found that the effect of bacterial reduction by ozone water was better than that by steady state ClO2 solution under optimized thawing conditions.3. Effects of ozone water and steady state ClO2 solution on bacterial reduction were studied during duck breast shashlik salting process. The results indicated that optimal parameters for bacterial reduction when treated by ozone water solution were: introducing ozone to the salting solution to a concentration of 0.6 mg/L, and treat for 14min at 10℃. Compared with the control, the total number of colonies in salting solution was reduced from 2.3×103 cfu/g to 0.6×102 cfu/g. The results indicated that optimal parameters for bacterial reduction when treated by steady state ClO2 solution were:adding steady state ClO2 to the salting solution to a concentration of 16 mg/L. and treat for 18 min at 19 ℃. Compared with the control, the total number of colonies in salting solution was reduced from 2.3×105 cfu/g to 0.7×102 cfu/g. Salting solution and duck breast strings were poured into a tumbler for forward and reverse tumbling after treated with ozone or steady state ClO2, and then they were put into a 4℃ cold storage for 16 hours. Compared with the control, the total number of colonies in duck breast strings using salting solution treated by ozone was reduced from 8.2 ×103 cfu/g to 1.4 ×103 cfu/g. The total number of colonies in duck breast strings salted with salting solution treated by steady state ClO2 was reduced from 8.2 ×103 cfu/g to 2.1×103 cfu/g. Through comparative analysis it was found that bacterial reduction effects of ozone treated salting solution was better than that of steady state ClO2 treated solution.4. Hurdle bacterial reduction system for duck breast string production process was optimized, and verified by production in Hunan Province KouKouXiang Industrial Co.. Ltd.. The optimized hurdle bacterial reduction system for duck breast string production process was as follows:after each workshop was disinfected by 100mg/L of steady state ClO2 spray, put 28 Kg frozen raw duck breast meat into 200 L cold water containing 7.7 mg/L ozone to thaw completely at 10 ℃; and then they were cut and separated, and inserted by bamboo sticks; then the strings were treated at 10℃ for 14min after the salting solution was introduced with ozone to a concentration of 0.6 mg/L. Salting solution and duck breast strings were then poured into a tumbler to forward and reverse tumbling for 5 min, and were put into a 4℃cold storage for 16 hours. Then after baking, stewing, and vacuum packaging, semi-finished products were made before sterilization. This experiment showed that the hurdle system had significant effects on bacterial reduction. Compared with the control, the total number of colonies in semi-finished products after vacuum-packaging was reduced from 2.1×104 cfu/g to 2.5×103 Cfu/g, and the efficacy of bacterial reduction reached 88%.5. With the semi-finished products generated by hurdle bacterial reduction technology and traditional process as raw materials, effects of high temperature and high pressure sterilization and irradiation sterilization on the quality and shelf life of leisure duck breast strings were studied. The results showed that, comparing to semi-finished products produced by conventional technology, vacuum packaged products produced by hurdle bacterial reduction technology can not only ensure the effective shelf life, but also decrease the time of high temperature and pressure sterilization from 30 min to 20 min and improve the sensory quality of the products. When comparing the effects of different sterilization methods on the sensory quality and shelf life of the product, the product sensory quality by irradiation sterilization is much better than that by heat-sterilization; however, irradiation sterilized products showed growth of microorganisms in the sixth month. |
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