| Cantaloupe(Cucumis melo var.Saccharinus)enjoys high popularity both at home and abroad.It has large size,and needs to be peeled and seeded when eating,so it is not convenient to eat.Fresh-cut cantaloupe has satisfied the desire of consumers to seek more convenience in daily life because of its fresh and convenient features.Fresh-cut cantaloupe is becoming more and more popular with its advantages,such as convenience,low calorie,diversification and shortcut,and has a broad market prospect.However,the microbial pollution and improper storage temperature shorten the shelf life of the fresh-cut cantaloupe.Therefore the extension of shelf life has always been a problem in the processing of fresh-cut fruits.This study mainly investigated the bactericidal effect of heat treatment on fresh-cut cantaloupes,the effect of different storage temperature on their storage quality.And the hazard analysis and key control points of fresh-cut cantaloupe was determined based on the freshcut cantaloupe processing technology.Results would provide theoretical basis to standardize the industrial production of fresh-cut cantaloupe in our country.The main research contents and results are as follows:1.Impact of heat treatment on the bactericidal effect and quality of fresh-cut cantaloupes:The fresh-cut cantaloupe samples were placed in a cold room at 4℃.On the 8d of storage,the microbial population of fresh cut cantaloupe samples of three treatment groups(70℃/30s,70℃/45s and 70℃/60s)were 5.541g(CFU/g),5.411g(CFU/g),and 5.841g(CFU/g),respectively.While the microbial population of fresh-cut cantaloupes in the 70℃/15s treatment group reached 6.011g(CFU/g)and exceeded the edible microbiological standard,resulting in the loss of commodity value.Results of the sensory evaluation of fresh-cut cantaloupes,the samples of the control group had a few visible spots and were not edible on the 8d of storage;the samples of the 70℃/15s treatment group showed a slightly dull color,creamy feeling and slightly milder sweet taste;the samples of the 70℃/60s treatment group showed partly ripeness,poorer brittleness,dry film on the surface,and obvious smooth creamy feeling;While the fresh-cut cantaloupe of 70℃/30s and 70℃/45s treatment groups still maintained normal melon color,bright cut surface,good crispness,sweetness and deliciousness which meaned that they still kept high commodity values.Therefore,the heat treatment of 70℃/30s～45s was considered to be the best heat treatment method.Also,the results showed that the microbial population in heat treated water increased as the increase of the usage time of heat treatment water;but it still had a good bactericidal effect.the use of heat-treated water for 2 hours would be the critical value regard of the total microbial population in the heat-treated water.It is recommended that the heat-treated water needs to be replaced every 2 hours during the process of industrial production.2.Effects of different storage temperature on storage quality of heat treated fresh-cut cantaloupe:The fresh cut cantaloupe were stored at(-1±0.5)℃,(11.0.5)℃,and(3±0.5)℃,respectively.The microbial population,sensory indexes,water content,titratable acid content,hardness,soluble solids content,crude fiber content and POD activity,and of fresh-cut cantaloupe were measured.The results showed that compared with 3℃ treatment group,-1℃ and 1℃ treatment group could better inhibit the growth of microbial population of fresh-cut cantaloupes,delay the decrease of water content,hardness,soluble solids content and POD activity;Meanwhile,the 1℃ treatment group could better maintain the color and titratable acid content of fresh-cut cantaloupes,and delay the increase of crude fiber content,compared with the-1℃ treatment group.On the eighth day of storage,the sensory quality of fresh-cut cantaloupe stored at 1℃ was better than that of the-1℃ and 3℃ groups.Also,on the eighth day of storage,the fresh-cut cantaloupes first stored at-1℃,1℃,and 3℃ were transferred to the cold room of(4±0.5)℃ to simulate the refrigerator temperature during the actual sale stage.On the first day of the storage at 3℃,the microbial population of fresh-cut cantaloupe were 6.21g(CFU/g),which means that they had lost their commodity value.The shelf life of fresh-cut cantaloupes stored at-1℃ and 1℃ were approximately 3d and 5d,respectively.Compared with the-1℃ storage group,the shelf life of fresh-cut cantaloupes stored at 1℃ could be prolonged by 2d.Therefore,a comprehensive analysis confirmed that 1℃ was the best storage temperature for fresh-cut cantaloupes,and fresh-cut cantaloupe could be stored for 13 days at 1℃.3.The effect of platform time on the microbial population of freshcut cantaloupe during the process of exiting the storehouse,and the establishment of HACCP system of cantaloupe.Under the environment temperature of 32℃,the fresh-cut cantaloupes simulated the process of exiting the storehouse and loading.After a certain time period of sitting on the platform,the fresh-cut cantaloupe were put back into the cold room at 4℃.On the second day of storage,the total number of residual colonies of fresh-cut cantaloupe in the different treatment groups varied in the platform sitting time of Omin(CK),30min,60min,90min and 120min,were3.231g(CFU/g),3.341g(CFU/g),3.801g(CFU/g),3.891g(CFU/g),5.881g(CFU/g),respectively.The microbial population of fresh-cut cantaloupe using platform sitting time of 30min was not significantly different from that of the CK group,but the microbial population of fresh-cut cantaloupe group staying in platform for 120min was 2.651g(CFU/g)higher than that of the CK group,with extremely significant difference(p<0.01).The results indicated that the time of platform placement would be a significant and extremely serious hazard to fresh-cut cantaloupe.Therefore,it is recommended that fresh-cut cantaloupes should not be placed on the flatform for more than 30min after leaving the cold room.Through the hazard analysis of fresh-cut cantaloupe,five key control points for fresh-cut cantaloupe as CCP points were identified as follows:raw material acceptance,heat treatment sterilization,metal detection,storage and exiting the storehouse,transportation and sales.Their own critical limits were also determined.In addition,the HACCP system of fresh-cut cantaloupes was first discussed and established in order to ensure their food safety. |
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