Study On The Intervention Technology Of Chicken Carcass By Electrolyzed Water Spray

In 2016,the consumption of chicken was second only to pork and has become a pillar meat industry in China.But in recent years,the outbreak of H7N9 has caused a certain impact on China's chicken industry,and the chicken production and consumption have had a few wobbles.At the same time,the transition of China's chicken production and consumption pattern has been taken place in this stage.Centralized slaughtering and refrigerated transport,which has been generally recognized as a safer and more efficient pattern,have gradually become popular with the consumers.Chilled chicken meat fits the current consumer demand because of its safe and nutritional characteristics and its market-share continues to increase.However,some defects still exist during chicken slaughter such as cross-contamination and the poor performance of the cleaning procedure,which leads to the high initial microbial loads and short shelf-life of the chilled chicken carcass which restricts the further development of chicken industry.Therefore,it is imperative to improve the intervention technology during chicken slaughter to reduce the initial microbial loads and prolong the shelf life of the chilled chicken carcass.This work firstly started by selecting the appropriate disinfectants to optimize the intervention technology.This work compared the effects of acid electrolyzed water(AEW)and slightly acid electrolyzed water(SAEW)sprays with various conventional disinfectant sprays on initial microbial load of the chicken carcasses and conduct a shelf-life study of the chilled chicken carcasses stored on 4?.Secondly,this work determined some physicochemical properties of AEW and SAEW,which may be involved in its practical application such as storage stability,metal corrosion and chlorate residues,in order to provide technical reference for the further application of electrolyzed water in the actual production process.Thirdly,this work improved the intervention technology by designing new cleaning equipment and a new type of U-shape rotary spray cleaning equipment whichcould achieve a more efficient and thorough cleaning of the chicken carcass was developed.Finally,this work evaluated the effect of the new electrolyzed water spray intervention technology on chicken carcass by combining the electrolyzed water with the U-shape rotary spray cleaning equipment.The main contents are as follows:1?The effects of various disinfectant sprays on reducing the initial microbial load and extend the shelf-life of chilled chicken carcassesApplication of 2%LA,AEW and SAEW sprays for 15 s were effective in reducing the total viable counts(TVC)and total coliforms in different parts of chicken carcass.Application of 2%LA,AEW and SAEW sprays for 15 s were effective in inhibiting the growth of microorganism on chicken carcass during storage.Samples treated with AEW and SAEW exceeded the TVC limit at day 8,2 days later compared to the controls which exceeded the TVC limit at day 6.These disinfectant sprays could also inhibit the growth of total coliforms,pH,total volatile basic nitrogen(TVBN)during storage.Predominantly,the thiobarbituric acid reactive substances(TBARS)values of the AEW and SAEW treated samples were not statistically different from those of the controls(P>0.05);however,the 2%LA treatment accelerated lipid oxidization,manifested as the highest TBARS value at day 8 which is detrimental to the carcass.2?Physicochemical properties of electrolyzed water60 mg/L AEW had severe,middle and slight corrosion effect to metals like carbon steel,aluminum,and bronze,respectively;whereas the 30 mg/L SAEW had milder corrosion effect on metals like carbon steel,aluminum and bronze,classified as middle,slight corrosion and no corrosion effects.However,the aforementioned two types of electrolyzed water had no corrosion effects on 304 stainless steels.At various storage conditions,the ACC and ORP of these two types of electrolyzed water showed the trends of decline,while the pH values changed in the adverse direction.The results revealed that storage conditions,such as low-temperature or sealed,were effective approaches to maintain the stability of ACC,pH values and ORP of AEW and SAEW,yet block the light during the storage period had no significant(P>0.05)influence on physicochemical properties of electrolyzed water.Applications of 60 mg/L AEW and 30 mg/L SAEW sprays to chicken carcasses for 15 s,resulted in a significant lower(P<0.05)residual content of chlorate on chicken carcasses than the 100mg/L sodium hypochlorite sprayed samples.Moreover,the residual content of chlorate on chicken carcasses of these treatments were lower than the recommended limitation of WHO.3?Design of the U-shape rotary spray chicken carcass cleaning machineThis section mainly dealt with the design of the overall structure of the U-shape rotary spray chicken carcass cleaning machine,and optimized the nozzole arrangement of each spray system.Besides,selections of major components and accessories,such as water pump,tube diameters,nozzles and valves,were also fully considered:A universal solid cone nozzle with a spray angle of 60°,a pressure of 0.3 MPa,and a flow rate of 3 L/min was used;The main water supply pipe diameter DN1 was set at 65 mm,the diameter of each branch pipe DN2 was set at 25 mm;A centrifugal pump with a lifting head of 60 m and a flow rate of 37 m3/h was used to boost water supply.The 304 stainless steel ball valve with a diameter of 65 mm and was used to adjust the flow and lift4?Functional tests of the U-shape rotary spray chicken carcass cleaning machineThe spray pressure of the spray units of this cleaning machine was around 0.3 MPa,the rate of flow was approximately 3 L/min,and no significant differences were observed in spray pressure and flow rate for near-water side spray nozzles of different spray units.However,in the same spray unit,the spray pressure and flow rate of near-water side were higher than the far-water side.Application of this new-type cleaning machine to chicken carcasses subsequent to its evisceration or prechilling sections could reduce 0.8-1.2 log CFU/cm2 and 0.7-1.1 log MPN/cm2 of the TVC and total coliforms,respectively.