JFS M: Food Miroiology nd Sfety of Browning nd Miroil Growth on Fresh-Cut Apples y Sequentil Tretment of Snitizers nd Clium Asorte HUA WANG, HAO FENG, ANDYAGUANG LUO ABSTRACT: This study investigted the effiy of different snitizers, inluding idi eletrolyzed wter (), peroxyeti id (), nd hlorine, on the intivtion of Esherihi oli O7:H7 on fresh-ut pples. The effets of the snitizers nd sequentil tretments of or followed y lium sorte (CA) on rowning inhiition nd orgnolepti qulities of fresh-ut pples stored under different pkge tmospheres t C were lso evluted. Chnges in pkge tmosphere omposition, produt olor, firmness, totl eroi teril ounts, yest nd mold ounts, nd sensory qulities were exmined t,,,, nd d. Among ll snitizer tretments, nd hieved the highest redution on E. oli O7:H7 popultions. The sequentil tretment of followed y CA (-CA) hieved the est overll dul ontrol of rowning nd teril growth on fresh-ut pple wedges. Pkge tmospheres hnged signifintly over time nd mong pkge mterils. Pkges prepred with films hving n oxygen trnsmission rte (OTR) of hd signifintly lower O nd higher CO prtil pressures thn those prepred with OTR films nd the Ziplo TM gs. The effet of pkge tmospheres on the rowning of pples is more pronouned on,, nd -CA-treted pple wedges thn on -CA-treted smples. Keywords: rowning, lium sorte, eletrolyzed wter, fresh-ut pple, peroxyeti id Introdution Fresh-ut pples hve emerged s populr food snks t oth retil nd food servie setors, nd re frequently inluded in shool lunh progrms (Wrren ). The prodution nd onsumption of fresh-ut pples re projeted to ontinue growing s more onsumers demnd fresh, onvenient, nd nutritious foods. A hllenge to the fresh-ut pple industry is the drkening of pple flesh fter utting used y enzymti-rowning retions. Currently, wsh solutions ontining lium sorte (CA) s the prinipl ingredient re used in fresh-ut pple prodution to inhiit enzymti-rowning retions nd to mintin qulity nd prolong shelf life (Chen nd others 999). CA is reltively expensive hemil nd hene the wshing solution is usully reused to redue prodution osts. The reuse of CA solution, however, results in n umultion of nutrients, miroorgnisms, nd even humn pthogens, if present, whih renders the wshing solution soure of ontmintion. The detetion of Listeri monoytogenes on slied pples (US FDA ) ws thus onsidered s possile onsequene of suh ontmintion (Krirhimoglu nd others ). Reently, in wshing experiment with ommeril CAsed solution, Bhgwt nd others () onluded tht the wshing solution should not e reused on multiple thes of slied pples euse of lk of ntiteril tivity. Efforts hve een mde in reent yers to find n effetive method to ontrol possile miroil ontmintion during fresh-ut pple wshing opertions. Krirhimoglu nd others () found tht MS Sumitted /9/, Aepted //. Author Wng nd Feng re with Dept. of Food Siene nd Humn Nutrition, Univ. of Illinois t Urn-Chmpign, Urn, IL, U.S.A. Author Luo is with Produe Qulity nd Sfety Lortory, USDA, ARS, Bltimore Ave., Beltsville, MD 7, U.S.A. Diret inquiries to uthor Feng (E-mil: hofeng@uiu.edu). plnktoni L. innou popultion ws redued y to nd log CFU/mL fter 9 h tretment in CA solutions with ph of. nd., respetively. Pilizot nd Spers () developed n idi rowning inhiition formultion tht did not support Listeri survivl or growth euse of low ph (.9). The survivl of enteri pthogens, inluding L. monoytogenes nd E. oli O7:H7, in wshing solutions with different ph ws exmined y Bhgwt nd others (). For the wshing solution with ph of, greter thn -log redution ws oserved fter treting seleted plnktoni pthogeni miroorgnisms with the solution for ht C. The emphsis of previous studies ws minly pled on inhiiting pthogen growth in tretment solutions rther thn on disinfeting fresh-ut pples tht ould hve een ontminted y humn pthogens during peeling, oring, nd sliing. Few studies evluted tehniques for the simultneous intivtion of foodorne pthogens nd ontrol of rowning in fresh-ut pples. Fn nd others () used irrdition to tret slied pples inoulted with L. monoytogenes suspension in CA solution. The dose of. kgy tht n hieve -log redution in L. monoytogenes popultion hd no signifint effet on qulity, exept loss in firmness, during d storge t C. Another pproh to hieving oth intivtion of foodorne pthogens nd inhiition of rowning is the use of wshing solutions with oth snitizing nd ntirowning pities. Chlorintion of wsh wter t onentrtion of up to mg/l is routinely pplied to redue miroil popultions in produe proessing lines (Wei nd others 9). However, the use of hlorine is of onern due to the formtion of hrmful y-produts (Rihrdson nd others 99), rpid depletion under high orgni loding, requirement for ph djustment of hlorine, nd hlorine gs off during proessing. There is hene muh interest in the development of sfer nd more effetive snitizers. Aidi eletrolyzed wter () nd peroxyeti id (, lso lled Tsunmi s produed y Eol) re new snitizers tht hve een tested in reent studies. M: Food Miroiology & Sfety C 7 Institute of Food Tehnologists Vol. 7, Nr., 7 JOURNAL OF FOOD SCIENCE M doi:./j.7-...x Further reprodution without permission is prohiited
Browning nd miroil growth ontrol for fresh-ut pples... M: Food Miroiology & Sfety hs strong teriidl effet ginst pthogens nd spoilge miroorgnisms due to omined tion of free hlorine (< mg/l), low ph (. to.7) nd high oxidtion redution potentil (ORP) ( mv) (Wng nd others ). hs een reported to work etter thn hlorinted wter for intivting E. oli O7:H7, Slmonell enteritidis, nd L. monoytogenes on seleted fresh produe nd met produts (Prk nd others ; Bri nd others ). is mixture of eti id (CH COOH) nd hydrogen peroxide (H O ) in n queous solution. The snitizing effiy of is not ffeted y orgni lod, solution ph, nd temperture nd it n rpidly rek down fter use into wter, oxygen, nd eti id (Anon. ). Beuht nd others () reported tht mg/l ws more effetive in reduing popultions of L. monoytogenes on lettue thn hlorine solution of mg/l. Outreks ssoited with pple ider nd pple juie indited tht E. oli O7:H7 ws tolernt to low ph onditions (Yokoigw nd others ). E. oli O7:H7 hs een found to grow exponentilly in wounds on Golden Deliious pples with ph of out. (Jnisiewiz nd others 999). Survivl of E. oli O7:H7 on ut surfes of pples hs lso een oserved y Spers nd others (), Riordn nd others (), nd Gunes nd Hothkiss (). It is therefore neessry to exmine the survivl of this orgnism on ut surfes of pples when treted with ntirowning nd ntimiroil solutions. The min ojetives of this study were to investigte teriidl ility of,, nd CA solutions on E. oli O7:H7 on fresh-ut pple surfes nd to explore the fesiility of omining seleted snitizers with CA solution to ontrol oth rowning retions nd miroil growth on the surfes of fresh-ut pples under modified tmosphere onditions. Mterils nd Methods Preprtion of tretment solutions ws generted using n genertor (ROX-TA, Hoshizki, Ngoy, Jpn) nd olleted from the node of the genertor in snitized ekers. The ph nd ORP of the were mesured with n AR ph nd ORP meter (Aumet Reserh, Pittsurgh, P., U.S.A.) nd the residul hlorine onentrtion ws determined using n EPA-pproved hlorine olorometri test kit (Model PCT-DR, LMotte Co., Chestertown, Md., U.S.A.). ( mg/l; Tsunmi ; Eol, St Pul, Minn., U.S.A.) ws prepred ording to the mnufturer s instrution. The onentrtion of ws mesured with test kit provided y the mnufturer. Chlorine solution ws prepred with onentrted food grde leh nd the ph ws djusted to. with. N HCl. The ville hlorine ws determined with hlorine test kit. Chlorine onentrtion ws ontrolled t mg/l. CA solution (%) ws prepred y dissolving solid CA (CA; Spetrum hemil & lortory produts, New Brunswik, N.J., U.S.A.) in sterilized deionized wter ( C) nd used within min. nd were prepred h prior to the test nd stored t C until use. Sterilized deionized wter ws used s the ontrol. Inoulum preprtion E. oli O7:H7 (DD) ultures were trnsferred times to trypti soy roth (ph 7., Difo Lortories, Detroit, Mih., U.S.A.) y loop inoultion t suessive -h intervls nd inuted t 7 C. Bteril ells were hrvested, fter h of growth, y entrifugtion ( g) t C for min. The ell pellets were wshed twie in slt peptone (.% NCl,.% Bto Peptone), nd resuspended in ml of.% peptone wter. The finl onentrtion of E. oli O7:H7 in the inoulum, determined y plting seril dilutions on Soritol MConkey Agr (SMAC, Difo Lortories) nd inuting t 7 C for h, ws pproximtely CFU/mL. Smple preprtion nd tretment proedures GoldenDeliiouspples (Mlus domesti Borkh) were otined from lol produe provider, kept t C, nd used within d. The sound, defet-free pples of uniform size nd shpe (7-mm di) were orded nd then ut into wedges with sterilized knives. For eh tretment, 9 wedges (. g±. g per wedge) were prepred. Freshut pples were wshed with : (w/v) rtio of pples to one of the following tretment solutions: sterilized deionized wter, (ph.7, ORP mv, nd free hlorine mg/l), ( mg/l), nd sequentil wsh with or followed y CA (%, ph., -CA, -CA). The wshing solution ws irulted y sumerged pump (E- N, Little Gint Pump Co., Oklhom City, Okl., U.S.A.) for min for ll the tretments exept the sequentil wsh in whih min or wsh ws followed y min CA wsh. In the sequentil tretment, the residul or on produe surfe ws removed y mnully operted sld spinner (OXO nd Good Grips, Elmir, N.Y., U.S.A.) for min efore CA wsh. Three piees of dewtered smples (verge. g ±. g) were pkged in one of the kinds of gs: polypropylene gs ( m 7 m) with film oxygen trnsmission rte (OTR) of nd ml/(d m ), respetively, nd Ziplo TM Sndwih & Snk gs (.. m). Smples were then stored t C for up to d. Qulity evlutions of smples were performed on,,,, nd d. For qulity evlution, pkges (or totl of 9 wedges) per tretment were used. In the nlysis of smples from eh of the pkges, the sensory nd olor evlution were mde on ll wedges efore g ws opened. Then, wedge from the g ws used for miroiologil test nd the other for texture mesurement. In E. oli O7:H7 intivtion tests, g of Golden Deliious wedges were sumerged in. L of teril inoulum ontining CFU/mL E. oli O7:H7 for min with gentle gittion. The inoulted pple slies were drined nd ir-dried for min in lminr flow iologil hood (Lono Purifier PCR Enlosure, Knss City, Mih., U.S.A.) efore tretments. Inoulted pple smples, out. g eh, were then sumerged in one of the tretment solutions: sterilized deionized wter, (ph.7, ORP mv, nd free hlorine 7 mg/l), ( mg/l), hlorine (ph., free hlorine mg/l), nd CA (%, ph.) with n pple to solution rtio of : t C for min with gittion t rpm with n gittor (Thermolyne Cimre, Duuque, Iow, U.S.A.). One wedge (out. g) ws removed from the solutions t the th min nd immeditely drined. The drined smple ws trnsferred to sterile stomher g for miroiologil nlysis. Anlysis of gs omposition The prtil pressures of O nd CO in the pkges were determined using n O nd CO nlyzer (PBI Dnsensor, Chekmte 99, Ringsted, Denmrk). Prior to opening pkges for nlysis, ruer septum ws tthed to eh pkge nd gs smple tken using.-in G needle. Color mesurement A Minolt Chrom Meter CR- (Minolt Corp., Osk, Jpn) ws used to ssess the olor of pple wedges. Considering olor vritions mong ut surfes of pples within the sme g, redings per wedge ( redings on eh side) nd redings per g were tken to ensure tht the dt otined truly represented the olor M JOURNAL OF FOOD SCIENCE Vol. 7, Nr., 7
Browning nd miroil growth ontrol for fresh-ut pples... of the smples. The mens of L,, nd from redings were reorded on eh smpling dy. Texture mesurement The firmness of the pple wedges ws determined using TA- XT Texture nlyzer (Texture Tehnologies Corp., Srsdle, N.Y., U.S.A.) with TA- - ylinder proe ( mm ID). The middle portion of eh wedge ws ut into. mm. mm. mm (W L H) ue to void the slnt wedge slipping when the proe pressed it. The pek fore of the mesurement ws used to determine the firmness of pple wedges. Three mesurements were onduted for eh pkge. Miroiologil nlysis Apple wedges (. g ±. g per wedge) from eh pkge were merted in ml.% (w/v) sterile slt peptone wter for min with stomher lender (L-Blender, Cooke Lortory Produts, Alexndri, V., U.S.A.). The homogente ws filtered through sterile glss-wool, serilly diluted in peptone wter, nd plted ( µl in triplite) on n pproprite medium. The totl eroi plte ount (TAPC) ws determined y plting the smples on tryptise soy gr (TSA, Difo Lortories) nd inuting t 7 C for h. Yest nd mold enumertion ws performed y ulturing with potto dextrose gr (PDA, Difo Lortories) nd inuting t C for to d. The finl E. oli O7:H7 popultion from inoulted smples treted with snitizers or CA ws determined ypltingserildilutionsofthehomogenteon SoritolMConkey Agr (SMAC; Difo Lortories) nd inuting t 7 C for h. Sensory evlution The extent of dey, rowning, nd eptility of pple wedges ws evluted y 7-memer trined pnel following modified proedure from Loiz nd Cntwell (997). Dey ws sored on to sle, where = none, = slight (up to % surfe ffeted), = moderte (% to % surfe ffeted), = modertely severe (% to % surfe ffeted), nd = extreme (> % surfe ffeted). Browning ws evluted on sle of to, where = none, = slight, = moderte, = severe, nd = extreme rowning. The eptility ws evluted on 9 to sle, where 9 = exellent, no defets, 7 = very good, minor defets, = fir, moderte defets, = poor, mjor defets, nd = extremely poor. Sttistil nlysis Three replite smples of eh tretment were tken from single experiment. Dt were nlyzed using SAS (SAS institute, Cry, N.C., U.S.A.). The effet of tretments nd pkge types, s well s the intertion etween tretments nd pkge types, ws exmined using the GLM proedure. The orreltion etween gs omposition nd olorimetri vlues ws nlyzed using the CORR proedure. The Fisher s LSD test ws used to determine differenes mong mens t α =.. Results nd Disussion Effet of tretments on redution of E. oli O7:H7 popultion Preliminry tests showed tht wshing fresh-ut pples for min hieved more teri popultion redution thn -min or -min wshing (for -min nd -min wshes, the redution ws in the rnge of. to. nd.9 to.9 log, respetively). To etter distinguish the differenes used y different tretments, -min wshing time ws used in oth the E. oli intivtion tests nd the qulity omprison tests. The initil ount of E. oli O7:H7 inoulted onto fresh-ut pple surfes ws. ±. log CFU/g tissue. Wshing with,, or hlorine removed signifintly (P <.) higher numers of E. oli O7:H7 ells thn did wter or CA tretments (Tle ). There ws no signifint differene (P >.) on E. oli O7:H7 redution etween the wter nd CA tretment. With -min wsh, nd redued E. oli O7:H7 popultion y.7 nd. log CFU/g, respetively, while CA nd wter tretments removed no more thn. log CFU/g. The (free hlorine 7 mg/l) hieved greter redution of miroil popultions thn did hlorine (free hlorine mg/l). The ws the most effetive snitizer mong the snitizing gents tested. Pkge tmosphere The CO prtil pressure inresed grdully while O prtil pressure deresed during storge mong ll tretments (Figure ). The pkges prepred with nd OTR films hd signifintly (P <.) higher CO prtil pressure nd lower O prtil pressure thn the Ziplo gs within the sme tretment during the storge. The lower CO umultion nd high O prtil pressure in the Ziplo gs re minly used y the fst gs exhnge due to the lose sel of the pkges. Generlly, O levels in OTR gs were slightly lower thn those in the OTR gs due to the lower O trnsmission rte. Apple wedges in OTR nd OTR gs mintined O prtil pressure ove the reommended optimum O prtil pressure (%) for fresh-ut pples (Fn nd others ). The responses of fresh-ut pples to different tretments during storge were slightly different. It n e seen from Figure ( ) tht the CO prodution from the -CA-treted smples strted to slowdown from th dy, nd t th dy, the CO prtil pressure of -CA tretment were signifintly lower thn tht of other tretments in ll the gs exept the ontrol in pkges with the OTR film (P <.). It seems -CA tretment redued the respirtion tivity of pple slies fter d, whih my hve n impt on the qulity of the smples. For the -CA tretment, CO prtil pressure experiened fst inrese until d, whih ws ompnied y fst depletion of O during the sme period. Exept the -CA tretment, other treted smples exhiited gs omposition similr to -CA-treted smples during storge. This pttern my suggest tht the inresed respirtion ws used more y tissue wounding from utting opertions thn y dmge resulting from wshing with the oxidizing gents. Bur nd others () wshed fresh-ut lettue with ozonted nd hlorinted wter nd oserved tht there were no signifint differenes etween smples treted with the snitizers nd the ontrol (wter) for the hnges of O nd CO in pkges during storge t C. They suggested tht the gs omposition in pkge ws determined more y the degree of wounding through utting thn y the individul tretments. Fn nd others () lso reported tht the hnges in hedspe omposition of fresh-ut pples indued y irrdition t. kgy nd. kgy were not signifintly different from the ontrol ( kgy). Tle --- E. oli O7:H7 popultion redution on inoulted pple smples fter -min tretment Tretment Wter CA Chlorine Popultion redution (Log CFU/g tissue).9 ±.. ±..9 ±..7 ±..7 ±. Initil ounts of E. oli O7:H7 on the pple piees were. ±. log CFU/g tissue (men ± stndrd devition). Dt followed y different letters in the sme olumn re signifintly (P <.) different mong the tretments. M: Food Miroiology & Sfety Vol. 7, Nr., 7 JOURNAL OF FOOD SCIENCE M
Browning nd miroil growth ontrol for fresh-ut pples... Color The olorimetri redings nd L for pple slies during storge re presented in Figure. A high nd low L vlue indited more rowning of fresh-ut pple surfe (Spers nd Dougls 97). The olor redings of pple tissues from the sme tretment pked in kinds of gs did not show signifint differenes (P >.) t dy nd other storge dys, whih indited tht the permeility of the pkging mterils ws not key ftor determining the rowning retions. This is in greement with the oservtion of Soliv-Fortuny nd others () in study to exmine the effet of modified tmosphere pkging on rowning retions of pple ues in pkging mterils. For ll kinds of pkges, tretment resulted in signifintly higher (P <.) nd signifintly lower L vlues ompred to other tretments. This trend my result from more severe pple-tissue dmge used y wsh so tht more polyphenol oxidse ws relesed out of the pple ells to promote oxidtion of phenoli sustrtes of pple tissues. The inhiitory effet of CA on rowning retions ws evidened y low nd high L vlues in -CA nd -CA-treted smples in omprison with the - nd -lone tretments. For the -CA sequentil tretment, the effet of CA on rowning ontrol seemed to e depressed fter d. Although the CO nd O prtil pressures for -CA-treted pple wedges were signifintly different from other tretments fter d (Figure ), the lower CO nd higher O in this tretment fter d did not orrespond with redued rowning, inditing tht the gs omposition during storge does not hve diret impt on rowning retions. A orreltion nlysis ws onduted to determine the role plyed y the gs omposition in olor hnges (Tle ). For, % to % of the olor hnges were used y hnges in CO nd O prtil pressure, wheres for L, only % to % of the hnges in lightness ould e ttriuted to gs omposition. Texture Figure shows the firmness of fresh-ut pples stored for d nd d. There were no signifint differenes in firmness loss (P >.) for the sme tretment mong pkging gs on either storge dy. On the th dy, the tretment in OTR gs used the most firmness loss, signifintly lower (P <.) thn the ontrol nd -CA tretments. Tests on the th dy did not find signifint differenes in firmness redution mong smples pked in OTR gs nd Ziplo gs. At the end of storge ( d), smples treted with -CA were signifintly less firm (P <.) in ll pkge types thn other tretments exept for the -wshed pple wedges in the OTR gs. Similr to the ontrol, the -CA tretment retined firmness etter thn other tretments t the st dy, regrdless of the pkging used, with the exeption of smples wshed with nd pked in OTR gs. This my suggest tht the CA tretment, when omined with, funtioned to retrd firmness redution of fresh-ut pples. Fn nd others () lso notied tht CA tretment redued firmness loss of ioni irrdited fresh-ut pples during storge. It ws postulted tht the C might hve helped to inhiit stress-indued senesene in pples y mintining memrne integrity (Fn nd others ). -CA -CA OTR OTR d - CA - CA Figure --- Chnges in O nd CO prtil pressures of different pkges ontining fresh-ut pples sujeted to different wsh tretments. Dt represent mens ± stndrd devition of replitions. M: Food Miroiology & Sfety CO (%) OTR Ziplo g OTR e Ziplo g f O (%) Storge time (dy) Storge time (dy) M JOURNAL OF FOOD SCIENCE Vol. 7, Nr., 7
Browning nd miroil growth ontrol for fresh-ut pples... 7 7 OTR -CA -CA OTR Figure --- Effet of wsh tretments nd pkge types on L nd vlues of fresh-ut pples during storge t C. Dt represent mens ± stndrd devition of replitions. 7 7 7 -CA -CA OTR OTR - - Colormetri Vlue (L*) 7 7 7 7 7 - Colormetri vlue (*) 7 Storge time (dy) Ziplo g Ziplo g - 7 7 7 7 - Storge time (dy) - Storge time (dy) Tle --- Correltion etween O or CO prtil pressure nd olorimetri vlues nd L during storge Correltion oeffiient (R ) CO O CO O Pkge ompred ompred ompred ompred type with with with L with L OTR...9. OTR.... Ziplo g.... nd L vlues were nlyzed for their orreltion with O or CO prtil pressure with lumped mens from ll tretments of eh pkge type. In the sequentil tretment of followed y CA, the gret loss in firmness on the st dy my e used y the lrge yest nd mold popultions oserved in miroil tests. Miroiologil nlysis There were less thn -log totl eroi teri nd no yest nd mold deteted on unwshed fresh-ut pples, whih were reltively len when otined from lol mrket nd proessed under sterile onditions. On dy, no signifint differenes (P >.) in TAPC were found etween the ontrol (sterilized wter) nd the snitizing tretments in eh pkge type (Figure ). During storge, grdul inrese in TAPC ws oserved for ll the tretments nd pkging gs. Although vriility in the response of miroflor to the snitizing tretments ws oserved during storge, similr to tht reported y Spers nd others (), the wsh exhiited etter inhiition to eroi teril growth thn other tretments. The elevted CO prtil pressure in OTR nd OTR gs did not limit the growth of miroflor. Insted, retrded growth of eroi teri, ompred to other pkging mterils, ws oserved in Ziplo gs tht hd lower CO prtil pressure. The yest nd mold ounts on fresh-ut pples t the st dy of storge re shown in Figure. There ws no yest or mold growth on fresh-ut pples treted with,, -CA, or -CA until the th dy. On the st dy signifint growth in yest nd mold ws oserved for ll pkging gs. Sttistilly, the growths in OTR, OTR, nd Ziplo gs were ll signifintly (P <.) different if dt from ll the tretments in type of pkging re lumped together for the omprison. A signifint (P <.) intertion ws lso found etween pkging types nd tretments in their effet on yest nd mold popultion. Yest nd mold popultions on pple wedges treted with nd -CA were signifintly (P <.) lower thn ontrol,, nd -CA in ll pkges. Ziplo gs nd OTR film llowed etter growth of yest nd mold in smples treted with nd -CA. In ll pkge types, -CA tretment resulted in the highest yest nd mold popultions s it did for totl eroi teri popultion t the end of storge. This my indite tht -CA tretment filitted fvorle onditions for miroil growth. Sensory evlution Sine the totl eroi teri strted to grow rpidly fter storge dys, sensory ttriutes were ompred nd reported only M: Food Miroiology & Sfety Vol. 7, Nr., 7 JOURNAL OF FOOD SCIENCE M
Browning nd miroil growth ontrol for fresh-ut pples... Firmness (N) 7 th dy st dy -CA -CA Figure --- Effet of wsh tretments nd pkge types on firmness of fresh-ut pples during storge t C OTR OTR Ziplo g Pkge type OTR OTR Ziplo g -CA -CA OTR -CA -CA st dy M: Food Miroiology & Sfety Totl eroi plte ount (log CFU g - tissue) OTR Storge time (dy) Ziplo g Figure --- Effet of wsh tretments nd pkge types on the totl eroi plte ount (TAPC) of fresh-ut pples during storge t C. Dt represent mens ± stndrd devition of replitions. * * elow detetion OTR OTR Ziplo g Figure --- Effet of wsh tretments nd pkge types on the yest nd mold ounts of fresh-ut pples during C storge. Below detetion level (< CFU/g tissue). helped improve the visul qulity s shown y eptility vlues in the rnge of. to 7., nd. to 7. for the tretments, respetively. The use of CA retrded dey, s well s rowning (Figure ) up to d, proly y meliorting tissue injury used y snitizing tretments. In this study, the CO prtil pressure (<.%) hd no effet on the qulity of fresh-ut pples s the gs with different CO prtil pressure on the th dy showed similr sores for the sme tretment in visul evlution. Gunes nd Hothkiss () reported tht CO prtil pressure of % helped to mintin visul qulity for pple slies during -d storge t C. It is therefore suggested tht test with higher CO prtil pressure should e onduted to evlute the shelf life of pple slies treted with snitizers used in this study. It n e seen from Figure nd tht higher TAPC did not orrespond to high degree of dey. The ontrol hd TAPC higher thn other tretments t the th dy for smples in OTR nd OTR gs. However, the highest dey ourred for smples treted with (Figure ) in the gs of the sme pkging film. The tretment resulted in more rowning (low L nd high ) on the th dy thn other tretments, nd hene greter tissue dmge. Therefore, the dey ws more relted to the tissue dmge thn to TAPC on the th dy. for dt t dy (Figure ). The eptility of tretment t dy rnged from. to., lowest mong ll tretments in ll the pkges. The sequentil tretments, -CA nd -CA, Conlusions exhiited the strongest effiy in reduing E. oli O7:H7 popultion on fresh-ut pples mong ll snitizers tested in M JOURNAL OF FOOD SCIENCE Vol. 7, Nr., 7
Browning nd miroil growth ontrol for fresh-ut pples... Sore 9 7 OTR OTR Ziplo g ontrol -CA -CA OTR OTR Ziplo g OTR OTR Ziplo g Pkge type Aeptility Dey Browning none Figure --- Effets of wsh tretments on dey, rowning, nd eptility of fresh-ut pples t th dy t C. Dey ws sored on sle to sle, where = none, = slight, = moderte, = modertely severe, nd = extreme. Browning ws evluted on sle of to, where = none, = slight, = moderte, = severe, nd = extreme rowning. The eptility ws evluted on 9 to sle, where 9 = exellent, no defets, 7 = very good, minor defets, = fir, moderte defets, = poor, mjor defets, = extremely poor. this study. However, used more qulity degrdtion thn other tretments. The sequentil tretment of followed y CA (-CA) ided in rowning ontrol for up to d ut smples treted with either or -CA hd severe rowning t the end of storge. The sequentil tretment of followed y CA resulted in less rowning, slower miroil growth, nd higher visul qulity sores thn ll other tretments nd ws hene promising tretment for fresh-ut pple prodution for the dul ontrol of rowning nd teri growth. Aknowledgments This reserh ws supported in prt y the U.S. Dept. of Agriulture, Agriulturl Reserh Servie (USDA Speifi Coopertive Agreement No. -7--), nd the Illinois Agriulturl Experiment Sttion. The uthors re grteful to Smnth Fernndes for her lortory ssistne during experimenttion nd Ellen Turner for her ssistne in the writing revision. Referenes Anon.. Food surfe tretment. Aville from: http://www.eol.om/ Inititives/foodsfety/FST/. Aessed August. Bri ML, Sin Y, Isoe S, Uemur T, Isshiki K.. Effetiveness of eletrolyzed idi wter in killing Esherihi oli O7:H7, Slmonell enteritidis, nd Listeri monoytogenes on the surfes of tomtoes. J Food Prot :. Bur S, Klier R, Hmmes WP, Crl R.. Sensory nd miroiologil qulity of shredded, pkged ieerg lettue s ffeted y pre-wshing proedures with hlorinted nd ozonted wter. Innov Food Si Emerging Tehnol :. Beuht LR, Adler BB, Lng MM.. Effiy of hlorine nd peroxyeti id snitizer in killing Listeri monoytogenes on ieerg nd romine lettue using simulted ommeril proessing onditions. J Food Prot 7:. Bhgwt AA, Sftner RA, Aott JA.. Evlution of wsh tretment for survivl of foodorne pthogens nd mintenne of qulity hrteristis of fresh-ut pple slies. Food Miroiol :9. Chen C, Trezz TA, Wong DWS, Cmir WM, Pvlth AE inventors; Mntrose-Heuser Co., In., ssignee. 7 August 999. Methods for preserving fresh fruit nd produt thereof. U.S. ptent,99, 7. Fn X, Niemer BA, Mettheis JP, Zhung H, Olson DW.. Qulity of fresh-ut pples slies s ffeted y low-dose ionizing rdition nd lium sorte tretment. J Food Si 7:. Fn X, Sokori KJ, Sommers CH, Niemer BA, Mttheis JP.. 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