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|標題:||Investigation of the Microbial Quality and Residues of Chemical Reagents in Fresh-Cut Vegetables in Taiwan, and the Application of Gamma Irradiation on the Extension of Their Shelf-life
|關鍵字:||fresh-cut vegetables;生鮮截切蔬菜;microbial quality;chemical residues;irradiation;sensory evaluation;微生物;化學藥劑殘留;輻射照射;品評||出版社:||食品暨應用生物科技學系所||引用:||1.IFPA (International Fresh-cut Produce Association) and PMA (The Produce Marketing Association). 1999. Handling guidelines for the fresh-cut produce industry (3rd ed.). Alexandria, VA: IFPA. p. 5. 2.Zhu LQ, Zhou J, Zhu SH, and Guo H. Inhibition of browning on the surface of peach slices by short-term exposure to nitric oxide and ascorbic acid. Food Chemistry. 2009. 114: 174-179. 3.Fischer R and Bennett A. Role of cell wall hydrolases in fruit ripening. Annual Review of Plant Physiology and Plant Molecular Biology. 1991. 42: 675-703. 4.Gemma OO, Ma Alejandra RG, Laura AG, Paula V, Robert SF, Ma Isabel HH, Isabel PM, Susana F, and Olga MB. Recent approaches using chemical treatments to preserve quality of fresh-cut fruit: A review. Postharvest Biology and Technology. 2010. 57: 139-148. 5.Manzano M, Citterio B, Maifreni M, Paganessi M, and Comi G. Microbial and sensory quality of vegetables for soup packaged in different atmospheres. Journal of the Science of Food and Agriculture. 1995. 67: 521-529. 6.Fang TJ, Wei QK, Liao CW, Hung MJ, and Wang TH. Microbiological quality of 18oC ready-to-eat food products sold in Taiwan. International Journal of Food Microbiology. 2003. 80: 241- 250. 7.Abadias M, Usall J, Anguera M, Solsona C, and Viñas I. Microbiological quality of fresh, minimally-processed fruit and vegetables, and sprouts from retail establishments. International Journal of Food Microbiology. 2008. 123: 121-129. 8.Odumeru JA, Mitchell SJ, Alves DM, and Farbe JM. Assessment of the microbiological quality of ready-to-use vegetables for health-care food services. Journal of Food Protection. 1997. 60: 954-960. 9.Garg N, Churey JJ, and Splittstoesser DF. Effect of processing condition on the microflora of fresh-cut vegetables. Journal of Food Protection. 1990. 53: 701-703. 10.Francis GA and O’Beirne D. Effect of the indigenous microflora of minimally processed lettuce on the survival and growth of Listeria innocua. International Journal of Food Science and Technology. 1998. 33: 477-488. 11.Sinigaglia M, Albenzio M, and Corbo MR. Influence of process operations on shelf-life and microbial populations of fresh cut vegetables. Journal of industrial microbiology and biotechnology. 1999. 23: 484-488. 12.Lack WK, Becker B, and Holzapfel WH. Hygienic quality of pre-packed ready-to-serve salads in 1995. Archiv für Lebensmittelhygiene. 1996. 47:129-152. 13.Mosupye FM and Holy AV. Microbiological quality and safety of street-vended foods in Johannesburg city, South Africa. Journal of Food Protection. 1999. 62: 1278-1284. 14.http://www.fda.gov.tw/files/people_laws/第(三)類-抗氧化劑_991126.pdf (2011/03/27) 15.http://www.fda.gov.tw/files/people_laws/第(十一)類-調味劑_991126.pdf (2011/03/27) 16.http://www.fda.gov.tw/files/people_laws/第(二)類-殺菌劑-20100504.pdf (2011/03/27) 17.http://www.fda.gov.tw/files/people_laws/第(四)類-漂白劑-20100504.pdf (2011/03/27) 18.http://www.accessdata.fda.gov/SCRIPTs/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=173.300 (2011/03/27) 19.http://www.accessdata.fda.gov/SCRIPTs/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=173.325 (2011/03/27) 20.http://www.comlaw.gov.au/Details/F2011C00123 (2011/03/27) 21.http://www.codexalimentarius.net/search/advancedsearch.do/download/standards/261/CXS_177e.pdf (2011/03/27) 22.http://www.fda.gov.tw/people_laws.aspx?peoplelawssn=474&keyword=&classifysn=62&key_laws=02 (2011/03/27) 23.http://www.foodstandards.gov.au/scienceandeducation/publications/guidelinesformicrobi1306.cfm (2011/03/27) 24.http://www.hc-sc.gc.ca/fn-an/res-rech/analy-meth/microbio/volume1/intsum-somexp-eng.php (2011/03/27) 25.http://www.fda.gov.tw/content.aspx?site_content_sn=324 (2011/03/27) 26.www.food.gov.uk/multimedia/pdfs/microcriteria2005reg.pdf (2011/03/27) 27.http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1259151921557 (2011/03/27) 28.http://www.cfs.gov.hk/english/whatsnew/whatsnew_act/files/MBGL_RTE%20food_e.pdf (2011/03/27) 29.Allende A, McEvoy J, Tao Y, and Luo Y. Antimicrobial effect of acidified sodium chlorite, sodium chlorite, sodium hypochlorite, and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro. Food Control. 2009. 20: 230-234. 30.Lee SY, Costello M, and Kang DH. Efficacy of chlorine dioxide gas a sanitizer of lettuce leaves. Journal of Food Protection. 2004. 67: 1371-1376. 31.Chang JM and Fang TJ. Survival of Escherichia coli O157:H7 and Salmonella enterica serovars Typhimurium in iceberg lettuce and the antimicrobial effect of rice vinegar against E. coli O157:H7. Food Microbiology. 2007. 24: 745-751. 32.Beuchat LF. 2000. Use of sanitizers in raw fruit and vegetable processing. In: Alzamora S.M., Tapia M.S., & Lopez-Malo A. (Eds.), Minimally processed fruits and vegetables (pp. 63-78). Maryland: Aspen. 33.Parish ME, Beuchat LR, Suslow TV, Harris LJ, Garret EH, Farber JN, and Busta FF. Methods to reduce/eliminate pathogens from fresh and fresh-cut produce. Comprehensive Reviews in Food Science and Food Safety. 2003. 2: 161-173. 34.Sapers GM and Sites JE. Efficacy of 1% hydrogen peroxide wash in decontaminating apples and cantaloupe melons. Journal of Food Science. 2003. 68: 1793-1797. 35.Grant GT, Morris ER, Rees DA, Smith PJC, and Thom D. Biological interactions between polysaccharides and divalent cations: the egg-box model. FEBS Letters. 1973. 32: 195-198. 36.Aguayo E, Escalona V, and Artés F. Effect of hot water treatment and various calcium salts on quality of fresh-cut ‘Amarillo’ melon. Postharvest Biology and Technology. 2008. 47: 397-406. 37.Hisaminato H, Murata M, and Homma S. Relationship between enzymatic browning of cut lettuce and phenylalanine ammonia-lyase activity, and prevention of browning by inhibitors of polyphenol biosynthesis. Bioscience Biotechnology and Biochemistry. 2001. 65: 1016-1021. 38.Loaiza-Velarde JG, Tomas-Barberan FA, and Saltveit ME. Effect of intensity and duration of heat-shock treatments on woundinduced phenolic metabolism in Iceberg lettuce. Journal of the American Society for Horticultural Science. 1997. 122: 873-877. 39.Gartner U, Mayer-Miebach E, and Spiess WEL. 1997. Controlling the microbial load on ready-to-use sliced salads by lowtemperature blanching. In: Jowitt R. (Ed.), Engineering and food at ICEF 7 (pp. J41-J42). Sheffield: Sheffield Academic Press. 40.Palou E, Lopez-Malo A, Barbosa-Canovas GV, and Welti-Chanes J. 2000. High hydrostatic pressure and minimal processing. In: Alzamora S.M., Tapia M.S., & Lopez-Malo A. (Eds.), Minimally processed fruits and vegetables (pp. 205-222). Maryland: Aspen. 41.Niemira BA, Fan X, and Sokorai KJB. Irradiation and modified atmosphere packaging of endive influences survival and regrowth of Listeria monocytogenes and product sensory qualities. Radiation Physics and Chemistry. 2005. 72: 41-48. 42.Hsu SY. Effects of water flow rate, salt concentration and water temperature on efficiency of an Electrolyzed oxidizing water generator. Journal of Food Engineering. 2003. 60: 469-473. 43.Bari ML, Sabina Y, Isobe S, Uemura T, and Isshiki K. Effectiveness of Electrolyzed acidic water in killing Escherichia coli O157:H7, Salmonella enteridis, and Listeria monocytogenes on the surfaces of tomatoes. Journal of Food Protection. 2003. 66: 542-548. 44.Park EJ, Alexander E, Taylor GA, Costa R, and Kang DH. The decontaminative effects of acidic Electrolyzed water for Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on green onions and tomatoes with differing organic demands. Food Microbiology. 2009. 26: 386-390. 45.Grass ML, Vidal D, Betoret N, Chiralt A, and Fito P. Calcium fortification of vegetables by vacuum impregnation interactions with cellular matrix. Journal of Food Engineering. 2003. 56: 279-284. 46.Zhang L, Lu Z, and Wang H. Effect of gamma irradiation on microbial growth and sensory quality of fresh-cut lettuce. International Journal of Food Microbiology. 2006. 106: 348-351. 47.Leistner L. 1999. Combined methods for food preservation. In M. Shafiur Rahman (Ed.), Food preservation handbook (pp. 457-485). New York: Marcel Dekker. 48.Varoquaux P and Wiley RC. 1994. Biological and biochemical changes in minimally processed refrigerated fruits and vegetables. In: Wiley, R.C. (Ed.), Minimally Processed Refrigerated Fruits and Vegetables (pp. 226-268). New York: Chapman & Hall. 49.Wen HW, Chung HP, Chou FI, Lin IH, and Hsieh PC. Effect of gamma irradiation on microbial decontamination, and chemical and sensory characteristic of lycium fruit. Radiation Physics and Chemistry. 2006. 75: 596-603. 50.WHO, 1981. Wholesomeness of irradiated food: report of a Joint FAO/IAEA/WHO Expert Committee. In: World Health Organization Technical Report Series 659. WHO, Geneva, Switzerland, pp 36. 51.WHO, 1999. High-Dose Irradiation: Wholesomeness of food irradiated with dose above 10 kGy: report of a Joint FAO/IAEA/WHO Study Group. In: World Health Organization Technical Report Series 890. WHO, Geneva, Switzerland, pp 7. 52.Codex Alimentrarius Commission 1984. Codex General Standards for Irradiation Foods and Recommended International Code of Practice for the Operation of Radiation Facilities Used for the Treatment of Foods, CAC, Vol. XV, E-1, Food and Agriculture Organization of the United Nations Rome. 53.Satin M. Use of irradiation for microbial decontamination of meat: situation and perspectives. Meat Science. 2002. 62: 277-283. 54.Kim KH and Yook HS. (Actini diadeliciosa var. deliciosa cv. Hayward). Radiation Physics and Chemistry. 2009. 78: 414-421. 55.Prakash A, Manley J, DeCosta S, Caporaso F, and Foley D. The effects of gamma irradiation on the microbiological, physical and sensory qualities of diced tomatoes. Radiation Physics and Chemistry. 2002. 63: 387-390. 56.Lu Z, Yu Z, Gao X, Lu X, and Zhang L. Preservation effects of gamma irradiation on fresh-cut celery. Journal of Food Engineering. 2005. 67: 347-351. 57.Ramamoorthi L, Toshkov S, and Brewer MS. Effects of carbon onoxide-modified atmosphere packaging and irradiation on E. coli K12 survival and raw beef quality. Meat Science. 2009. 83: 358-365. 58.Yoksan R, Akashi M, Biramontri S, and Chirachanchai S. Hydrophobic chain conjugation at hydroxyl group onto γ-ray irradiated chitosan. Biomacromolecules. 2001. 2: 1038-1044. 59.Molins, RA. 2001. Food Irradiation chemistry. In Molins R.A. (Ed.), Food Irradiation: Principle and applications (pp. 47-55). Canada: John Eiley & Sons. 60.Ahn DU, Jo C, and Olson DG. Analysis of volatile components and the sensory characteristics of irradiated raw pork. Meat Science. 2000. 54: 209-215. 61.Gray JI, Gomma E, and Buckley DJ. Oxidative quality and shelf-life of meats. Meat Science. 1996. 43: S111-S123. 62.Stevenson MH. Nutritional and other implications of irradiating meat. Proceedings of the Nutrition Society. 1994. 53: 317-325. 63.Diehl JF and Josephson ES. Assessment of wholesomeness of irradiated foods. Acta Aliment. 1994. 32: 195-214. 64.Quintiliani M. The oxygen effect in radiation inactivation of DNA and enzymes. International Journal of Radiation Biology and Related Studies in Physics. Chemistry and Medicine. 1986. 50: 573-594. 65.Foley DM, Dufour A, Rodriguez L, Caporaso F, and Prakash A. Reduction of Escherichia coli O157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation. Radiation Physics and Chemistry. 2002. 63: 391-396. 66.Song HP, Byun MW, Jo C, Lee CH, Kim KS, and Kim DH. Effects of gamma irradiation on the microbiological, nutritional, and sensory properties of fresh vegetable juice. Food Control. 2007. 18:5-10. 67.Young LN, Jo C, Hwa SD, Geun KW, Woo BM. Effect of γ-irradiation on pathogens inoculated into ready-to-use vegetables. Food Microbiology. 2006. 23: 649-656. 68.Chaudry MA, Bibi N, Khan Misal, Khan Maazullah, Badshah A, and Qureshi MJ. Irradiation treatment of minimally processed carrots for ensuring microbiological safety. Radiation Physics and Chemistry. 2004. 71: 169-173. 69.Ahn HJ, Kim JH, Kim JK, Kim DH, Yook HS, and Byun MW. Combined effects of irradiation and modified atmosphere packaging on minimally processed Chinese cabbage (Brassica rapa L.). Food Chemistry. 2005. 89: 589-597. 70.Zhang L, Lu Z, Lu F, and Bie X. Effect of γ irradiation on quality-maintaining of fresh-cut lettuce. Food Control. 2006. 17: 225-228. 71.Mahrouz M, Lacroi M, D’Aprano G, Oufedjikh H, and Boubekri C. Shelf-life and quality evaluation of clementine following a combined treatment with r-irradiation. Radiation Physics and Chemistry. 2004. 71: 141-143. 72.Bidawida S, Farbe JM, and Sattar SA. Inactivation of hepatitis A virus (HAV) in fruits and vegetables by gamma irradiation. International Journal of Food Microbiology. 2000. 57: 91-97. 73.Lacroix M and Lafortune R. Combined effects of gamma irradiation and modified atmosphere packaging on bacterial resistance in grated carrots (Daucus carota). Radiation Physics and Chemistry. 2004. 71: 77-80. 74.Thayer DW, Rajkowski KT, Boyd G, Cooke PH, and Soroka DS. Inactivation of Escherichia coli O157:H7 and Salmonella by gamma irradiation of alfalfa seed intended for production of food sprouts. Journal of Food Protection. 2003. 66: 175-181. 75.Goularte L, Martins CG, Morales-Aizpuru’a IC, Destro MT, Franco BDGM, Vizeu DM, Hutzler BW, and Landgr M. Combination of minimal processing and irradiation to improve the microbiological safety of lettuce (Lactuca sativa, L.). Radiation Physics and Chemistry. 2004. 71: 155-159. 76.Hajare SN, Saroj SD, Dhokane VS, Shashidhar R, and Bandekar JR. Effect of radiation processing on nutritional and sensory quality of minimally processed green gram and garden pea sprouts. Journal of Food Protection. 2006. 69: 1858-1864. 77.Baskaran R, Devi AU, Nayak CA, Kudachikar VB, Prakash MNK, Prakash M,. Ramana KVR, and Rastogi NK. Effect of low-dose γ-irradiation on the shelf life and quality characteristics of minimally processed potato cubes under modified atmosphere packaging. Radiation Physics and Chemistry. 2007. 76: 1042-1049. 78.Todoriki S, Bari L, Kitta K, Ohba M, Ito Y, Tsujimoto Y, Kanamori N, Yano E, Moriyama T, Kawamura Y, Kanamori N, Yano E, Moriyama T, Kawamura Y, and Kawamoto S. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes. Radiation Physics and Chemistry. 2009. 78: 619-621. 79.CNS 10890. Method of test for food microbiology – Test of standard plate count (Aerobic plate count) 80.CNS 10984. Method of test for food microbiology – Test of coliform bacteria 81.CNS 10951. Method of test for food microbiology – Test of Escherichia coli 82.CNS 10981. Method of test for food microbiology – Test of Staphylococcus aureus 83.CNS 10952. Method of test for food microbiology – Test of Salmonella 84.NIEA W408.50A. http://www.niea.gov.tw/analysis/method/m_n_1.asp?m_niea= W408.51A (2011/04/08) 85.CNS 14575. Method of test for sulfur dioxide content of starches and derived products－Acidimetric method and nephelometric method 86.Novakova L, Solich P, and Solichova D. HPLC methods for simultaneous determination of ascorbic and dehydroascorbic acids. Trends in Analytical Chemistry. 2008. 27: 942-958. 87.Tran TT, Tran PH, Choi HG, Han HK, and Lee BJ. The roles of acidifiers in solid dispersions and physical mixtures. International Journal of Pharmaceutics. 2010. 384: 60-66. 88.Fan X and Sokorai KJ. Assessment of radiation sensitivity of fresh-cut vegetables using electrolyte leakage measurement. Postharvest Biology and Technology. 2005. 36: 191-197. 89.Paterson JE and Woodburn MJ. Klebsiella and other bacteria on alfalfa and bean sprouts at the retail level. Journal of Food Science. 1980. 45:492-495. 90.Lee SY and Baek SY. Effect of chemical sanitizer combined with modified atmosphere packaging on inhibiting Escherichia coli O157:H7 in commercial spinach. Food Microbiology. 2008. 25: 582-587. 91.Qin G and Meng Z. Effects of sulfur dioxide derivatives on expression of oncogenes and tumor suppressor genes in human bronchial epithelial cells. Food and Chemical Toxicology. 2009. 47: 734-744. 92.Saroj SD, Shashidhar R, Pandey M, Dhokane V, Hajare S, Sharma A, and Bandekar JR. Effectiveness of radiation processing in elimination of Salmonella Typhimurium and Listeria monocytogenes from sprouts. Journal of Food Protection. 2006. 69: 1858-1864. 93.Khattak KF, Simpson TJ, and Ihasnullah. Effect of gamma irradiation on the microbial load, nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome. Radiation Physics and Chemistry. 2009. 78: 206-212.||摘要:||
第一階段，8種即食截切蔬菜包含葉菜類、根莖類共42件，5種即煮截切蔬菜樣品共15件，2種芽菜類樣品共24件，進行微生物和化學藥劑殘留檢測。微生物檢測結果中，總生菌數菌數大於105 CFU/g、大腸桿菌群菌數大於103 MPN/g、和大腸桿菌菌數大於10 MPN/g為不合格，而金黃色葡萄球菌和沙門氏菌不可檢出。即食截切蔬菜產品的總生菌數共13件不合格、大腸桿菌群共12件不合格，大腸桿菌、金黃色葡萄球菌和沙門氏菌則未被檢出。其次，在即煮截切蔬菜15件產品中，有10件樣品的生菌數大於105 CFU/g，9件樣品的大腸桿菌超過103 MPN/g，因其食用前需煮過故可去除一般微生物故合格；而大腸桿菌、金黃色葡萄球菌和沙門氏菌皆未檢出。芽菜類24件所含之總生菌數與大腸桿菌群皆已超過衛生署所定的規範，且有2件樣品的大腸桿菌數也超過規範，而金黃色葡萄球菌和沙門氏菌則未被檢出。另外，所有芽菜類、即食截切蔬菜和即煮截切蔬菜的樣品在化學藥劑殘留測定中，均未檢出餘氯和二氧化硫的殘留，而抗壞血酸和檸檬酸都符合規定沒有超標。本實驗第二階段利用輻射線照射6種常見截切蔬菜(萵苣、高麗菜、苜蓿芽、豌豆苗、紅蘿蔔與馬鈴薯)。結果顯示截切蔬菜經照射後能有效降低微生物含量，樣品在低溫下存放9天後，高劑量(3 kGy)照射組與未照射組相比，葉菜類的總生菌數可降低約6 log CFU/g、芽菜類下降約4 log CFU/g，而根莖類降低約4-6 log CFU/g。另外，由酵母菌和黴菌數的檢測結果發現葉菜類和芽菜類可降低約6 log CFU/g，而根莖類下降約4-6 log CFU/g。此外，照射對蔬菜組織破壞程度以電解液釋出量(Electrolyte leakage)的多寡來判斷，在高劑量(3 kGy)照射下的EL值和其他劑量相比，明顯高於其他劑量，且隨著存放時間增加EL值亦會增加，故蔬菜組織的破壞程度會同時受到照射劑量和存放天數影響；照射後的樣品在低溫存放9天後，照射組的樣品和未照射組相比沒有顯著差異，照射對樣品色澤影響小。輻射照射過的樣品，以紅蘿蔔和高麗菜進行官能品評，以了解照射樣品對顧客喜好性的影響，其餘樣品因存放後會有水分滲出或外觀不佳不適食用。品評結果顯示，高麗菜在0.5 kGy劑量照射後，外觀分數略微下降(0.56%)而風味(7.22%)、質地(5.00%)和整體接受度(5.56%)皆上升。然而，在高劑量(2 kGy)照射的高麗菜，四種項目的分數皆下降，品評者對於樣品的接受度低。而紅蘿蔔在0.5 kGy劑量照射後，外觀(3.33%)、風味(2.22%)、質地(5.00%)和整體接受度(0.56%)皆下降，而在1 kGy劑量照射的紅蘿蔔，四種項目的分數皆上升，比0.5 kGy照射的紅蘿蔔好。高劑量(2 kGy)照射的紅蘿蔔，品評者對於樣品的總體接收度較照射1 kGy的樣品低。因此，高麗菜在0.5 kGy的劑量可以增加其感官品評，而紅蘿蔔則是在1 kGy的劑量可以增進其感官品評。
Fresh-cut fruits and vegetables are easy to have browning reactions and microbial contamination during the processing. Therefore, manufactories may add antioxidants or antibacterial agents to avoid the quality reduction of these products. Thus, the first part of this study was to investigate the microbial quality and the amounts of chemical residuals in fresh-cut vegetables. In the second part of this study, vegetables which are easily contaminated by microorganisms were irradiated to inhibit the growth of microorganisms and to increase its shelf life. Moreover, the effects of irradiation on the physical and sensory quality of vegetables were also investigated.
In the first part, a total of 42 ready-to-eat (RTE) vegetables (classified into leafy vegetable and rhizomes), 15 ready-to-cook (RTC) vegetables, and 24 sprout products were investigated. The total plate counts above 105 CFU/g, coliform counts above 103 MPN/g, and Escherichia coli counts above 10 MPN/g were unacceptable. In addition, Staphylococcus aureus and Salmonella spp. can't be detected. Among 42 RTE samples, 13 and 12 samples were unacceptable due to the too high amounts of total plate count and coliform count, individually; while, E. coli, S. aureus, and Salmonella spp. were not detectable in all RTE samples. For 15 RTC samples, 10 samples had total plate count higher than 105 CFU/g, and 9 samples had coliform count higher than 103 MPN/g. Since RTC products will be cooked before eating, it is sure that microorganisms normally can be eliminated before ingestion with proper cooking process. There was no contamination of S. aureus and Salmonella spp. in all RTC samples. All 24 sprout products were unacceptable in total plate count and coliform count. Moreover, two samples were contaminated by E. coli, but S. aureus and Salmonella spp. were not detectable in all sprout samples. Additionally, in all RTE, RTC, and sprout samples, no residual chloride and sulfur dioxide was detected, and the content of ascorbic acid and citric acid were all under the legal limits. In the second stage of this study, food irradiation was applied to six common vegetables (lettuce, cabbage, alfalfa sprouts, pea shoot, carrot, and potato). The results showed that gamma irradiation could effectively reduce the growth of microorganism. After the storage for 9 days, the log reduction for total plate counts could reach to 6 log CFU/g, 4 log CFU/g, and 4-6 log CFU/g for 3-kGy irradiated leafy vegetables, rhizome, and sprouts, respectively. Moreover, the log reduction of yeast and mold on leafy vegetables, rhizome, and sprouts were about 6 log CFU/g, 6 log CFU/g, and 4-6 log CFU/g, respectively. The damage level of food irradiation on tissues of vegetables was expressed by the electrolyte leakage value (EL). The EL values at 3 kGy dose were higher than other dosages for all test samples, and the EL also increased with the increase of storage time. Therefore, the tissues of vegetables were affected by both irradiation dose and storage time. After samples were stored for 9 days, the color of irradiated samples had no significant difference compared with non-irradiated samples. The irradiated cabbage and carrot were used to perform the sensory evaluation, for understanding the effects of irradiation on customer's preference. Due to other vegetables released water or had bad appearance after storage, they were not suitable for sensory evaluation. The appearance score of cabbage treated with 0.5 kGy dose slightly decreased (0.56%); however, odor score (7.22%), texture score (5.00%), and overall acceptability score (5.56%) were increase, as compared to un-irradiated cabbages. At high irradiation dose of 2 kGy, the score of four sensory items decreased, since most people didn't accept this level of irradiated cabbage. Moreover, the score of carrot treated with 0.5 kGy dose were decreased in appearance (3.33%), odor (2.22%), texture (5.00%), and overall acceptability (0.56%). At irradiation dose of 1 kGy, the score of four sensory items increased compared with carrot treated with 0.5 kGy dose. Carrot irradiated with 2 kGy dose had lower score in overall acceptability than that treated with 1 kGy. Therefore, irradiation dose at 0.5 kGy could improve the sensory and hygiene quality of cabbage, and irradiation dose at 1 kGy had better sensory effect on carrot.
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