research article shelf life determination of fresh blueberries...

Research ArticleShelf Life Determination of Fresh Blueberries(Vaccinium corymbosum) Stored under ControlledAtmosphere and Ozone

Anibal Concha-Meyer12 Joseph D Eifert1 Robert C Williams1

Joseph E Marcy1 and Gregory E Welbaum3

1Food Science and Technology Department Virginia Tech 1230 Washington Street SW Blacksburg VA 24061 USA2Centro de Estudios en Alimentos Procesados (CEAP) Avenida San Miguel 3425 3480137 Talca Chile3Horticulture Department Virginia Tech 1880 Pratt Drive Research Building XV Blacksburg VA 24061 USA

Correspondence should be addressed to Anibal Concha-Meyer anibalcmvtedu

Received 13 October 2014 Accepted 9 December 2014

Academic Editor Jaime Yanez

Copyright copy 2015 Anibal Concha-Meyer et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Fresh blueberries are commonly stored and transported by refrigeration in controlled atmospheres to protect shelf life for longperiods of storage Ozone is an antimicrobial gas that can extend shelf life and protect fruit frommicrobial contamination Shelf lifeof fresh highbush blueberries was determined over 10-day storage in isolated cabinets at 4∘C or 12∘C under different atmosphereconditions including air (control) 5 O

2

15 CO2

80 N2

(controlled atmosphere storage (CAS)) and ozone gas (O3

) 4 ppm at4∘C or 25 ppm at 12∘C at high relative humidity (90ndash95) Samples were evaluated for yeast and molds growth weight loss andfirmness CAS andO

3

did not delay or inhibit yeast andmolds growth in blueberries after 10 days at both temperatures Fruit storedat 4∘C showed lower weight loss values compared with 12∘C Blueberries stored under O

3

atmosphere showed reduced weight loss at12∘C by day 10 and loss of firmness when compared to the other treatments Low concentrations of ozone gas together with properrefrigeration temperature can help protect fresh blueberries quality during storage

1 Introduction

Blueberries are recognized for their contribution to a healthydiet with different beneficial bioactive compounds such asflavonoids anthocyanins and others [1 2] which helps toavoid important diseases including different cancers [34] Highbush blueberries (Vaccinium corymbosum) togetherwith the other commercial blueberry species are ranked as thesecondmost economically important berry after strawberriesin the US accounting for nearly 8509 million dollars in2012 [5] Although the US is the world biggest blueberryproducer the American market is so large that importing thefruit from other countries such as Chile is required In 2011Chile provided more than 50 of the imported blueberriessold in the US [6] Products shipped from Chile can take 20days to arrive to the US [7]

Proper storage for blueberries is around 0∘C with arelative humidity from 90 to 95 that provides a storagelife of 10ndash18 days [8] The use of controlled atmosphere infresh produce transportation is widely applied by producersto assure the quality of the product and avoid spoilageRespiration rate as well as deterioration decreases for somefruits when under CO

2levels of about 10 to 20 Bounous

et al [9] reported that O2concentrations between 8 and

10 andCO2concentrations of 10 to 13managed tomain-

tain the quality of blueberries between 5 and 8 weeks at 0-1∘C and 3 days at 18ndash20∘C According to Retamales et al[10] high levels of CO

2(20ndash30 kPa) in combination with low

levels of O2(5ndash10 kPa) helped control decay and extend shelf

life of cherries transported from Chile to Japan Moreoverreduction of Botrytis cinerea (grey mold rot) in strawberriescan be achieved by applying 15 CO

2[11] According to

Hindawi Publishing CorporationInternational Journal of Food ScienceVolume 2015 Article ID 164143 9 pageshttpdxdoiorg1011552015164143

2 International Journal of Food Science

Mitcham and Mitchell [12] grey mold rot and other decayorganisms can be minimized by using gas concentrationsof 15 to 20 carbon dioxide and 5 to 10 oxygen whichwill also decrease respiration and softening rates of shippedblueberries raspberries and blackberries thus prolongingpostharvest life

Ozone (O3) is a strong antimicrobial agent with variety of

applications in the food industry [13] Ozone was designatedas generally recognized as safe (GRAS) in 1982 by theUS Food and Drug Administration (FDA) for use as adisinfectant or sanitizer in the gas or liquid phase on food (21CFR Part 173) and for direct contact use as an antimicrobialfor treatment storage and processing on diverse foodsincluding raw and minimally processed fruits and vegetables[14] Ozone decomposes rapidly into oxygen without leavingresidues [15] and its postharvest applications have increased[16]Moreover its use in cold rooms helps reduce the ethylene(C2H4) level in air extending the storage life of fruits and

vegetables such as apples and oranges [17] Other studies haveproven inhibition of spoilage microorganisms and shelf lifeextension using O

3in bananas [18] potatoes onions and

beetroot [19] tomatoes andmandarins [20] blackberries [21]lettuce and carrots [22] and strawberries [23]

However other studies have found ozone to be ineffectiveto control spoilage on apples blueberries green beans musk-melons peaches and strawberries [24] Furthermore applescantaloupes cranberries and corn kernels showed increaseddecay and spoilage contamination when ozone was used onthem [25ndash27]

According to Palou et al [28] 03 ppm O3on peaches

and table grapes did not delay decay however grey mold wasinhibited on grapes Perez et al [23] found 035 ppmO

3ineffi-

cient to prevent fungal decay in addition to negative effects onthe sensory properties of strawberries Although highO

3may

be necessary for an effective elimination of microorganismsthis may alter negatively the sensory attributes of fresh fruit[29]

The present study evaluated shelf life extension and qual-ity preservation of fresh blueberries packaged under differentatmosphere conditions (Air controlled atmosphere storage(CAS) 5 O

2 15 CO

2 80 N

2 or Ozone) and tempera-

ture storage (4∘C or 12∘C) for 10 days

2 Materials and Methods

21 Fruit Samples The trial was carried out during the sum-mer of 2012 using highbush blueberries (Vaccinium corym-bosum L cv Ozark Blue) that were hand harvested fromthe commercial planting Three Birds Berry Farm locatedin Blacksburg VA Two replications were conducted eachconsisting of fruit harvested at two different dates Only fullycolored developed fruit without defects was selected on avisual basis

22 Fruit Storage After harvest collection samples werestored in a cooler (4ndash8∘C) and transported to the FoodScience and Technology Building at Virginia Tech Samplesconsisted of fifty blueberries stored in 44 oz PET perforated

retail clamshell boxes (HighlandCorporationMulberry FL)which were placed in a dessicator cabinet and incubated atdifferent temperatures (4∘C or 12∘C) and different atmo-sphere conditions (Air as a control (21 O

2and 003

CO2) 5 O

2 15 CO

2 80 N

2 Ozone) Ten samples were

analyzed on days 0 1 4 7 and 10 per storage temperature andatmosphere conditions

23 Controlled Atmosphere and Ozone Treatment Clearacrylic desiccator cabinets with exterior dimensions of1210158401015840W times 1210158401015840H times 1210158401015840D with gas ports including hygrometer(Cole-Parmer Lansing MI USA) were used to store fruit inclamshells inside an incubator (Precision IncubatorThermoScientific Waltham MA) and held at 4∘C or 12∘C with 90ndash95 relative humidity (RH) which was maintained placinga deionized water in an open sterilized petri dish inside thedesiccators Temperature and RHweremonitored by a sensor(Traceable JumboThermo-HumidityMeter Fisher ScientificPittsburgh PA)

For controlled atmosphere storage a certified standard-spec compressed gas tank (MID-Saint Louis SGL-MO) sup-plied an atmosphere of 5 O

2and 15 CO

2and balanced

with nitrogen (80) Gas concentrations were maintained byreflushing the cabinets aftermonitoring them two times a day(morning and late afternoon) using an O

2CO2gas analyzer

(O2CO2Check Point PBI-Dansensor Ringsted Denmark)

A corona discharge ozone generator (FreshFridge 20Refrigerator Air Purifier Model GH 2138 IonCare GandHIndustrial Ltd China) and a small air circulating fan wereinstalled in the chambers Ozone concentration in chamberswas monitored controlled and recorded continuously usingan ozone analyzer (Model ES-600 Ozone Solutions Inc IAUSA) and a Dell Latitude D830 computer as data logger(Dell Round Rock Texas) Ozone concentration mean andstandard deviation valueswere 40plusmn 18 ppm for 4∘Cand 25plusmn15 ppm at 12∘C A third chamber without an ozone generatorserved as the control (Air) Blueberries were exposed tocontrolled atmosphere and ozone in these chambers for atotal of 10 days

24 Weight Loss Each clamshell with fifty blueberries wasweighed after harvest and the reweighed after 1 4 7 and 10days of storage Weight was recorded using a scale with anaccuracy of 001 g and expressed as accumulated weight losspercentage per unit time

25 Yeast and Molds Yeast and Molds Petrifilm (3M Micro-biology Products St Paul MN) pouches were stored uno-pened at 4∘C To aseptically prepare 1 10 dilutions 10 g ofblueberries was added to a stomacher bag with 90mL ofsterile 01 peptone water (Difco Becton Dickinson SparksMD) Samples were blended and stomached for 120 seconds(AES Laboratoire Easy Mix Microbiology InternationalCombourg France) serially diluted and plated on Yeastand Mold Petrifilm in duplicate Plates were incubated inhorizontal position clear side up in stacks not exceeding 20units for 3 days at room temperature 20ndash25∘C

International Journal of Food Science 3

Yeasts appeared as blue-green or off-white in color andformed small defined edge colonies Mold colonies are usu-ally blue butmay also assume their natural pigmentation (egblack yellow and green) They tended to be larger and withmore diffuse edges than yeast colonies usually with a focusin a center of colony Yeast andmolds were enumerated usingthe AOAC official method 99702 [30]

26 Firmness Texture Analysis Textural measurements wereperformed on harvest day and during postharvest storageBlueberries samples for analysis were randomly selected andsample size was fifteen berries each testing as describedby Doslashving et al [31] The force required to penetrate eachblueberry fruit wasmeasured individually using a TAXTPlusTexture Analyzer and a 2mm diameter stainless steel punc-ture probe TA-52 (Stable Microsystems Godalming SurreyUK) The probe height was calibrated to 13mm above theTA-90 base platform so that the blueberry could be aligneddirectly under the probe and a 50Kg load transducer wasused The following test settings were used Measure Force inCompression Return to Start pretest speed of 2mms andtest speeds of 1mms with an automatic trigger set to 5 gramsof force and test distance of 3mm into the blueberries Eachtime a set of fruits was measured the equipment was forceand height calibrated

27 Experimental Design and Statistical Analysis Data wereanalyzed using the least squares method on JMP Pro 10 (SASInstitute Inc Cary NC) The randomized complete blockfactorial design with two replications was utilized to testthe treatments and their interactions on weight loss yeastand mold growth and texture firmness If the interactionsbetween treatments were not significant (119875 gt 005) the maineffects of the treatments were separated using Studentrsquos 119905-test

3 Results and Discussion

31 Weight Loss Although weight loss was minimal in thisstudy and ranged from018 to 264within 10 days of storagesignificant differences in treatments were observed mostly at12∘C storage Weight loss of fruit stored at 4∘C showed nosignificant difference among treatments or time of storage(Figure 1) According to literature to control weight loss ofblueberries it is crucial to keep low temperatures (0-1∘C)and high relative humidity during storage [32 33] Forney[34] found that maintaining a high relative humidity (95or greater) minimized weight loss and shrivel of blueberriesHowever this can increase decay development if condensa-tion is not properly controlled [35] Schotsmans et al [36]concluded that controlled atmosphere storage (25 kPa O

2+

15 kPa CO2) was favorable for long term blueberry storage

up to 42 days Furthermore a significant weight loss (9ndash14)was not observed until day 6 of exposure and the antioxidantactivities and total phenolic content of blueberries were notaffected adversely [36]

Despite the fact that in the present study the same ozona-tor device was used at 4∘C and 12∘C ozone gas concentrationaveraged 4 ppm and 25 ppm respectively in agreement with

00

05

10

15

20

25

30

1 4 7 10 1 4 7 10

Wei

ght l

oss (

)

Time (day)

AirCAS

a a a a a a a b ab

4∘C 12

∘CTemperature (∘C)

O3

a a a a a b a a ba b c a b c

Figure 1 Weight loss percentage of highbush blueberries stored at4∘C or 12∘C under controlled atmosphere storage conditions (CAS)ozone (O

3

) or regular atmosphere (Air) during 10 days Columnswithin each day at same temperature followed by the same lowercaseletter are not significantly different (119875 gt 005) from each other

Liew and Prange [24] who observed that residual ozoneconcentrations are lower at higher storage temperatures At astorage temperature of 12∘C O

3was the treatment that better

protected the fruit fromweight loss over time and values weresignificantly lower than weight loss under air and CAS atdays 1 4 7 and 10 (Figure 1) Sanford et al [33] reported thatmaximumweight loss before blueberries become nonsaleableis approximately 5 to 8 implying that in this study therewas not a loss of quality since values were far from this rangeThe results in this study are equivalent to other research thatshowed around 2 loss from initial weight after 10 days ofstorage at 5∘C and 10∘C [37] and minimal weight loss of 2after 14 days at 0∘C [38]

O3kept weight loss low and helped control decay at

12∘C while other authors found reciprocal results on storedhighbush blueberries at 10∘C for 7 days using 700 ppb and nophytotoxicity compounds were observed [39] According toKim et al [40] SO

2and O

3reduce weight loss and fruit decay

in blueberries increasing fruit quality and storage lifeIn the present study by day 10 CAS and air showed

no significant difference in weight loss at 12∘C implyingthat CAS is effective controlling weight loss in a long timestorage period Although Bounous et al [9] observed thatthree cultivars of highbush blueberries lostmoreweightwhenstored in air and O

3when compared to CAS at the end of 6

weeks storage CAS weight loss was higher than air and O3

Weight loss in fruit is directly related to respiration rate[38] A low O

2and rich CO

2atmosphere can potentially

reduce not only the respiration rate but also ethylene sen-sitivity and production oxidation and fruit decay [41 42]Moreover O

3inhibition of enzymatic reaction can cause a

decrease in fruit respiration leading to less weight loss [40]


Table 1 Yeast counts (log CFUg) and increase over 10 days (Δ) of highbush blueberries stored at 4∘C or 12∘C under controlled atmospherestorage conditions (CAS) ozone (O3) or regular atmosphere (Air)

Treatment 4∘C 12∘CDay 0 Day 10 Δ Day 0 Day 10 Δ

Air 301 plusmn 010 395 plusmn 027 094 301 plusmn 010 393 plusmn 015 092CAS 543 plusmn 005 730 plusmn 010 187 383 plusmn 030 642 plusmn 003 259O3 544 plusmn 005 729 plusmn 014 186 377 plusmn 036 614 plusmn 006 237

Other gases can produce a decrease of enzymatic activity infruit such as SO

2[40] Na

2S2O5sodium metabisulfite [43]

and CO2[9] According to Aguayo et al [44] O

3stimulated

the respiration rate in both whole and cut tomatoes onlyduring the first two days of storage decreasing after thatperiod Other authors have confirmed that O

3decreases

respiration rate in whole tomatoes [20 45] bananas [18] andpeaches [28] however Liew and Prange [24] observed anincrease on carrots under O

3treatments depending on doses

and storage timeThe ratio of CO2produced toO

2consumed

known as the respiratory quotient (RQ) is normally assumedto be equal to 10 if themetabolic substrates are carbohydrates[41] Beaudry et al [46] explained an observed RQ of 13 forblueberries by their high content of citric acid and sugarsThe RQ is much greater than 10 when anaerobic respirationtakes placeOxygen concentration should be lowbut not zeroto avoid anaerobic respiration on fruit stored in controlledatmosphere conditions In this study oxygen concentrationsunder CAS were 5

32 Yeast and Molds Yeast counts increased from day 0 today 10 along all treatments and temperatures (Table 1) Initialcounts in CAS and O

3were higher than in air At 12∘C yeast

population increases were higher in O3and CAS with 259

and 237 logCFUg increases respectively when comparedto 187 and 186 logCFUg at 4∘C Since fruits were collectedfrom the field and were not surface-sterilized before testingnaturally occurring yeast and molds were measured Highvariability of initial yeast and mold counts is influenced bytime of the year weather and harvest conditions as well asthe fruit wetness when picked [47] Moreover if the naturalprotective wax bloom of blueberries is absent due to weatheror picking practices it is more likely to grow yeast andmolds

Increases over time in mold counts were similar forblueberries stored in air (control) at 4∘C (274 logCFUg)and 12∘C (275 log CFUg) (Table 2) The increase over timeof mold for CAS blueberries at 4∘C (210 CFUg) was highercompared to 12∘C storage (020CFUg) Beuchat andBrackett[48] observed slower growth of molds at 10∘C when com-pared to 5∘C on lettuce Lower counts at warmer tempera-tures were observed by day 10 on O

3and CAS treatments

The increase in mold counts for the O3treatment at 4∘C was

calculated using the recovery counts of day 7 since at day 10at 4∘C no plate growth occurred at a detection limit of 10minus4Growth of visible mold on samples was only observed in airtreatment at 12∘C in day 10 (150 berries)

Ozone inhibition of bacteria is more noticeable thanin yeast and molds [13 44] Moreover Palou et al [49]

Table 2 Mold counts (log CFUg) and increase over 10 days (Δ) ofhighbush blueberries stored at 4∘C or 12∘C under controlled atmo-sphere storage conditions (CAS) ozone (O3) or regular atmosphere(Air)


Air lt100lowast 374 274 lt100lowast 375 275CAS 285 495 210 224 260 020O3 286 474lowastlowast 189 224 339 115lowastNo growth at limit of detectionlowastlowastMold counts at day 7 used because of no growth at day 10 due to high limitof detection

indicated that O3delays but does not reduce fungi incidence

after one week and cannot control molds in wounded fruitsOzone was fungistatic against grey mold (Botrytis cinerea)and not fungicidal [24] Ozone treatment was ineffective inpreventing fungal decay in strawberries after 4 days at 20∘C[23] According to Schotsmans et al [36] CA effectiveness todecrease fungal and blemish development is achieved after 28days of storage at refrigeration conditions

33 Firmness Table 3 shows that firmness penetration forcevalues were not significantly different (119875 lt 005) betweentreatments after 10 days of storage at 4∘C However at12∘C penetration force for the control berries (21977 g) wassignificantly higher compared to berries stored under O

3

(16919 g) and CAS (18267 g) According to Schotsmans et al[36] a high touch firmness value means the blueberry fruitis perceived as being softer The enhanced resistance of thefruit to the probe penetration can be interpreted as excessiveelasticity or gumminess due to a strong loss of internal waterturgor pressure [50] This characteristic is unfavorable sinceit can mislead fruit grading and texture determination [51]Turgidity is the most critical texture component in blueberry[50]

At 4∘C texture within O3treatments did not have signifi-

cant differences over time while air only showed differencesat day 1This latter observation could be caused by heat shockfrom harvest temperature to the refrigeration temperaturesAguayo et al [44] observed that the firmness of tomato slicesdid not change after cyclical O

3enriched airflow exposure

throughout 5∘C cold storage time when compared to controlHowever in whole tomatoes the O

3treatment reduced

softness Mushrooms treated with O3(003mg sminus1) for 15 or

30min showed no significant difference in firmness changeduring storage [52]


Table 3 Firmness penetration peak force (g) of highbush blueberries stored at 4∘C or 12∘C under controlled atmosphere storage conditions(CAS) ozone (O3) or regular atmosphere (Air) during 10 days

Firmness penetration peak force (g)Treatment Day 0 Day 1 Day 4 Day 7 Day 10

Temperature 4∘CAir 1780 plusmn 425Aa 1388 plusmn 237Ba 1808 plusmn 175Aa 1953 plusmn 463Aa 1856 plusmn 343Aa

CAS 1592 plusmn 247CDa 1830 plusmn 260ABb 1405 plusmn 209Db 1678 plusmn 362BCa 1944 plusmn 442Aa

O3 1592 plusmn 247Aa 1690 plusmn 266Ab 1701 plusmn 338Aa 1761 plusmn 391Aa 1734 plusmn 517Aa

Temperature 12∘CAir 1780 plusmn 425Aa 1676 plusmn 233Aa 1920 plusmn 175Aa 1795 plusmn 234Aa 2198 plusmn 573Ba

CAS 1960 plusmn 289Aab 1501 plusmn 268Bb 1385 plusmn 219Bb 1463 plusmn 184Bb 1827 plusmn 355Ab

O3 2028 plusmn 248Ab 1461 plusmn 151Bb 1531 plusmn 156Bc 1435 plusmn 161Bb 1692 plusmn 266Cb

Means within each row followed by the same capital letter are not significantly different (119875 gt 005) from each other Means within each column followed bythe same lowercase letter are not significantly different (119875 gt 005) from each other

At 12∘C CAS blueberries showed a significant increasein texture after day 0 (1960 g) when compared to day 1(1501 g) and day 4 (1385 g) Many reports can be found inliterature where strawberry firmness increased during lowtemperature storage [53 54] and high CO

2levels [55 56]The

firming effect of CO2and its magnitude are possibly cultivar

dependent [54] Moreover the indirect effects of CO2on the

apoplastic pH with the subsequent precipitation of solublepectins and the enhancement of cell-to-cell bonding [57]are likely responsible for the firming response [58] Higherfirmness of Bluecrop blueberries during storage could also berelated to the presence of stone cells in the fruit [59]

The firmness increase in CAS at 12∘C when comparingday 0 (1960 g) to day 7 (1463 g) is equivalent to the resultsof the study by Mahajan and Goswami [60] where litchi fruitfirmness increased achieving acceptable puncture strengthwithin the storage period perhaps because of the moistureloss from litchi fruit during storage which may be explainedby fruit drying and hardening characteristics In the presentstudy blueberries stored under CAS at 12∘C experiencehigh weight loss values when compared to ozone Pelayoet al [58] found a beneficial effect of CO

2during storage

increased firmness in two cultivars with no detectable effectson external color

Firmness testing of fruits is used to describe mechanicalproperties of the fruit tissue [61] and provides information onthe storability and resistance to injury of the product duringhandling [62] Instrumental measurements of texture arepreferred rather than sensory evaluation since instrumentsmay reduce variation among measurements due to humanfactors and are in generalmore precise [63]Thepresent studyresults show that the variations in texture between individualfruit are large in agreement with previous reports [31 62]

Texture is affected by cellular organelles biochemicalconstituents water content or turgor and cell wall compo-sition [64] High humidity allows degradation of the middlelamella and disintegration of the primary cell wall which areimportant factors determining fruit softening [65] Duringblueberry ripening the total water soluble pectin decreasesand the degradation of the cell wall and middle lamellais responsible for the loss of firmness [65] Changes in

the chemistry of the primary cell wall components cellulosepectins and hemicelluloses that occur during growth anddevelopment can also affect texture [66] This variation maybe attributed to cultivar differences andor their interactionwith postharvest storage conditions [67] In the present studythe only cultivar used was Ozark Blue under high humidityenvironments (90ndash95)

Absence of significant changes in firmness among treat-ments at 4∘C in the present study corresponds to the resultsobtained by Chiabrando et al [66] who found that dur-ing storage firmness of blueberries was not considered acritical quality factor Firmness remained constant duringpostharvest storage at 0∘C indicating that low-temperatureconditionsmay delay berry softening by inhibiting enzymaticactivities and ethylene production

The high variability of mean blueberry penetration forcemeasurements can be due to the different berry sizes withinthe samples Smagula et al [68] and Khazaei and Mann[69] reported that smaller blueberries tended to be slightlyfirmer than larger ones (confirming the negative relationbetween size and firmness of blueberries from the samecultivar [36 70]) Moreover Doslashving and Mage [62] andChiabrando et al [66] also observed a significant amountof fruit-to-fruit variability in firmness values Texture is noteasy to define particularly in small fruits such as blueberriessince a common standardized method does not exist Manyinstruments and techniques have been studiedwidely [62 71ndash77] and the majority of these methods record a measurementof the force needed to puncture penetrate or deform the fruit[66] In this study penetration firmness measurement wasconducted similar to other research with blueberries [78 79]

At 12∘C by day 10 the penetration peak force for blueber-ries stored in air was significantly higher on day 10 (2198 g)compared to days 0 (1780 g) 1 (1676 g) and 7 (1795 g) Thisincrease in firmnessmay be attributed tomoisture loss duringstorage which corresponds to fruit drying and hardeningcharacteristics [60 66] This behavior is due to the fact thata less turgid berry generally presents an extended tissuedeformation before the probe breaks the superficial tensionand enters into the plasticity phase where irreversible ruptureoccurs [50] A soft and more deformable and elastic berry


structure is probably by a water leakage as reported for otherproducts [80]

At day 10 themean forcemeasurement for each treatmentwas significantly different when compared to each otherIn whole tomatoes O

3treatment reduced softness after 15

days of storage providing a better retention of the textureof fruit compared to control [44] Das et al [81] observedthat an ozone gas concentration of 30mgL did not change orsoften texture of cherry tomatoes Fan et al [82] developedan in-package ozonation device which produced ozoneinside sealed film bags and showed no negative effects oncherry tomatoes texture preserving fruit quality after 22 daysposttreatment storage

At 12∘C fruit firmness increased initially in all treatmentswhen comparing day 0 and day 1 while firmness decreasedover storage time in agreement with results reported byAllan-Wojtas et al [59] Chiabrando et al [66] and Basiounyand Chen [83] in blueberries and Pelayo et al [58] in straw-berries Shriveling of blueberries over time was observedregardless of storage temperature in agreement with otherauthors [37 66]

4 Conclusion

Ozone was more effective controlling weight loss at 12∘Calthough weight loss in fruit was never more than 3 A highweight loss in fruit is a problem that is commercially sig-nificant for producers Naturally occurring yeast and moldson blueberries were not affected by CAS and O

3treatments

since they were able to grow over time at both temperaturesDuring storage time firmness was better maintained with O

3

and CAS treatment when compared to Air These treatmentscan be used during cold storage meaning an advantage toproducers who may wish to delay or extend marketing offruits [84] Ozone treatment did not cause external damage tothe blueberries The O

3treatment reported here can be used

in fresh highbush blueberries to maintain quality and extendshelf life Future research could study the impact of O

3and

CAS on flavor profiles using a sensory panel

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This paper is the result of a research sponsored by theVirginiaTech Department of Food Science and Technology

References

[1] M A Lila ldquoAnthocyanins and human health an in vitro inves-tigative approachrdquo Journal of Biomedicine and Biotechnologyvol 2004 no 5 pp 306ndash313 2004

[2] Y Wang C-F Chang J Chou et al ldquoDietary supplementationwith blueberries spinach or spirulina reduces ischemic braindamagerdquo Experimental Neurology vol 193 no 1 pp 75ndash842005

[3] International Agency for Research on Cancer IARCHandbooksof Cancer Prevention Volume 8 Fruit and Vegetables Interna-tional Agency for Research on Cancer Lyon France 2003

[4] World Cancer Research FundAmerican Institute for CancerResearch Food Nutrition Physical Activity and the Preventionof Cancer A Global Perspective American Institute for CancerResearch Washington DC USA 2007

[5] US Department of Agriculture Non-Citrus Fruit and Nuts 2012Preliminary Summary National Agricultural Statistics ServiceWashington DC USA 2013

[6] US Department of AgricultureNon-Citrus Fruits and Nuts 2011Summary National Agricultural Statistics ServiceWashingtonDC USA 2012

[7] R M Beaudry C E Moggia J B Retamales and J F HancockldquoQuality of lsquoIvanhoersquo and lsquoBluecroprsquo blueberry fruit transportedby air and sea from Chile to North Americardquo HortScience vol33 no 2 pp 313ndash317 1998

[8] J Bachmann and R Earles Postharvest Handling of Fruits andVegetables ATTRA 2000

[9] G Bounous G Giacalone A Guarinoni and C Peano ldquoMod-ified atmosphere storage of high bush blueberryrdquo Acta Horti-culturae vol 446 pp 197ndash203 1997

[10] J Retamales D Manrıquez P Castillo and B Defilippi ldquoCon-trolled atmosphere in bing cherries from Chile and problemscaused by quarantine treatments for export to Japanrdquo ActaHorticulturae vol 600 pp 149ndash153 2003

[11] J M Garcıa C Aguilera and M A Albi ldquoPostharvest heattreatment on Spanish strawberry (Fragaria x ananassa cvTudla)rdquo Journal of Agricultural and Food Chemistry vol 43 no6 pp 1489ndash1492 1995

[12] E JMitcham and F GMitchell ldquoPostharvest handling systemssmall fruits II Strawberries and cane berriesrdquo in PostharvestTechnology of Horticultural Crops A Kader Ed vol 3311 pp364ndash368 University of California Division of Agriculture andNatural Resources Oakland Calif USA 3rd edition 2002

[13] J-G Kim A E Yousef and S Dave ldquoApplication of ozone forenhancing the microbiological safety and quality of foods areviewrdquo Journal of Food Protection vol 62 no 9 pp 1071ndash10871999

[14] FDA ldquoGRAS status of ozonerdquo Federal Register vol 47 no 215pp 50209ndash50210 1982

[15] G CWhite ldquoOzonerdquo inHandbook of Chlorination andAlterna-tive Disinfectants pp 1046ndash1110 Van Nostrand Reinhold NewYork NY USA 1992

[16] M E Parish L R Beuchat T V Suslow et al ldquoMethods toreduceeliminate pathogens from fresh and fresh-cut producerdquoComprehensive Reviews in Food Science and Food Safety vol 2supplement 1 pp 161ndash173 2003

[17] L J Skog and C L Chu ldquoOzone technology for shelf lifeextension of fruits and vegetablesrdquo in Proceedings of the FourthConference on Postharvest R Ben-Aire and S Philosoph-HadasEds vol 2 of Acta Horticulturae 553 pp 285ndash291 ISHS 2000

[18] R Gane ldquoThe respiration of bananas in presence of ethylenerdquoNew Phytologist vol 36 no 2 pp 170ndash178 1936

[19] V A Baranovskaya O B Zapolskii I Y Ovrutskaya N NObodovskaya E E Pschenichnaya and O I YushkevichldquoUse of ozone gas sterilization during storage of potatoes andvegetablesrdquoKonservnaja i Ovoshecesushilrsquo naya Promyshlennostvol 4 pp 10ndash12 1979

[20] L Jin W Xiaoyu Y Honglin Y Zonggan W Jiaxun andL Yaguang ldquoInfluence of discharge products on post-harvest


physiology of fruitrdquo in Proceedings of the 6th International Sym-posium on High Voltage Engineering pp 1ndash4 New Orleans LaUSA August 1989

[21] MM Barth C ZhouMMercier and F A Payne ldquoOzone stor-age effects on anthocyanin content and fungal growth in black-berriesrdquo Journal of Food Science vol 60 no 6 pp 1286ndash12881995

[22] N Singh R K Singh A K Bhunia and R L Stroshine ldquoEffi-cacy of chlorine dioxide ozone and thyme essential oil or asequential washing in killing Escherichia coliO157H7 on lettuceand baby carrotsrdquo LWTmdashFood Science and Technology vol 35no 8 pp 720ndash729 2002

[23] A G Perez C Sanz J J Rıos R Olıas and J M Olıas ldquoEffectsof ozone treatment on postharvest strawberry qualityrdquo Journalof Agricultural and Food Chemistry vol 47 no 4 pp 1652ndash16561999

[24] C L Liew and R K Prange ldquoEffect of ozone and storage tem-perature on postharvest diseases and physiology of carrots(Daucus carota L)rdquo Journal of the American Society for Horti-cultural Science vol 119 no 3 pp 563ndash567 1994

[25] R I Brooks and A S Csallany ldquoEffects of air ozone and nitro-gen dioxide exposure on the oxidation of corn and soybeanlipidsrdquo Journal of Agricultural and Food Chemistry vol 26 no5 pp 1203ndash1209 1978

[26] J S Norton A J Charig and I E Demoranville ldquoThe effect ofozone on storage of cranberriesrdquo Proceedings of the AmericanSociety for Horticultural Science vol 93 pp 792ndash796 1968

[27] D H Spalding ldquoEffects of ozone atmospheres on spoilage offruits and vegetables after harvestrdquo Marketing Research Reportno 801 Agricultural Research Service US Dept of Agri-culture Washington DC USA 1968

[28] L Palou C H Crisosto J L Smilanick J E Adaskaveg and J PZoffoli ldquoEffects of continuous 03 ppmozone exposure on decaydevelopment and physiological responses of peaches and tablegrapes in cold storagerdquo Postharvest Biology and Technology vol24 no 1 pp 39ndash48 2002

[29] M Achen Efficacy of ozone in inactivating Escherichia coliO157H7 in pure cell suspensions and on apples [MS thesis] TheOhio State University Columbus Ohio USA 2000

[30] AOAC ldquoYeast and molds counts in foods Dry rehydratablefilmmethod Petrifilmmethodrdquo Official Method 99702 AOACInternational Gaithersburg Md USA 1998

[31] A Doslashving F Mage and S Vestrheim ldquoMethods for testingstrawberry fruit firmness a reviewrdquo Small Fruits Review vol 4no 2 pp 11ndash34 2005

[32] J Y Harb and J Streif ldquoControlled atmosphere storage of high-bush blueberries cv ldquoDukerdquordquo European Journal of HorticulturalScience vol 69 no 2 pp 66ndash72 2004

[33] K A Sanford P D Lidster K B McRae et al ldquoLowbushblueberry quality changes in response to mechanical damageand storage temperaturerdquo Journal of the American Society forHorticultural Science vol 116 no 1 pp 47ndash51 1991

[34] C F Forney ldquoPostharvest issues in blueberry and cranberry andmethods to improve market-liferdquo in IX International VacciniumSymposium K E Hummer Ed vol 810 of ISHS Acta Horti-culturae pp 785ndash798 ISHS 2008

[35] S A Sargent J K Brecht and C F Forney ldquoBlueberry harvestand postharvest operations quality maintenance and foodsafetyrdquo in Blueberries for Growers Gardeners Promoters N FChilders and P M Lyrene Eds pp 139ndash151 Painter PrintingDeLeon Springs Fla USA 2006

[36] W Schotsmans A Molan and B MacKay ldquoControlled atmo-sphere storage of rabbiteye blueberries enhances postharvestquality aspectsrdquo Postharvest Biology and Technology vol 44 no3 pp 277ndash285 2007

[37] M C N Nunes J-P Emond and J K Brecht ldquoQualitycurves for highbush blueberries as a function of the storagetemperaturerdquo Small Fruits Review vol 3 no 3-4 pp 423ndash4402004

[38] E D Jackson K A Sanford R A Lawrence K B McRaeand R Stark ldquoLowbush blueberry quality changes in responseto prepacking delays and holding temperaturesrdquo PostharvestBiology and Technology vol 15 no 2 pp 117ndash126 1999

[39] J Song L Fan C F Forney et al ldquoEffect of ozone treatmentand controlled atmosphere storage on quality and phytochem-icals in highbush blueberriesrdquo in VIII International ControlledAtmosphere Research Conference J Oosterhaven and H WPeppelenbos Eds vol 600 of ISHS Acta Horticulturae pp 417ndash423 ISHS 2003

[40] T J Kim J L Silva A Tokitkla and F B Matta ldquoModifiedatmosphere storage influences quality parameters and shelf lifeof lsquotifbluersquo blueberriesrdquo Journal of the Mississippi Academy ofScience vol 4 no 55 pp 143ndash148 2010

[41] S C Fonseca F A R Oliveira and J K Brecht ldquoModellingrespiration rate of fresh fruits and vegetables for modifiedatmosphere packagesa reviewrdquo Journal of Food Engineering vol52 no 2 pp 99ndash119 2002

[42] L Gorris and B Tauscher ldquoQuality and safety aspects of novelminimal processing technologyrdquo in Processing of Foods QualityOptimization and Process Assessment F A R Oliveira and J COliveira Eds pp 325ndash339 CRC Press Boca Raton Fla USA1999

[43] E Petri C Arroqui I Angos and P Vırseda ldquoEffect of preser-vative agents on the respiration rate of minimally processedpotato (Solanum tuberosum cv Monalisa)rdquo Journal of Food Sci-ence vol 73 no 3 pp C122ndashC126 2008

[44] E Aguayo V H Escalona and F Artes ldquoEffect of cyclic expo-sure to ozone gas on physicochemical sensorial and microbialquality of whole and sliced tomatoesrdquo Postharvest Biology andTechnology vol 39 no 2 pp 169ndash177 2006

[45] Y P Maguire M Solberg and N F Haard ldquoInfluence ofatmospheric oxygen and ozone on ripening indices of normal(Rin) and ripening inhibited (rin) tomato cultivarsrdquo Journal ofFood Biochemistry vol 4 no 2 pp 99ndash110 1980

[46] R M Beaudry A C Cameron A Shirazi and D L Dostal-Lange ldquoModified atmosphere packaging of blueberry fruiteffect of temperature on package O

2

and CO2

rdquo Journal of theAmerican Society for Horticultural Science vol 117 pp 436ndash4411992

[47] W O Cline ldquoPostharvest infection of highbush blueberries fol-lowing contact with infested surfacesrdquo HortScience vol 31 no6 pp 981ndash983 1996

[48] L R Beuchat and R E Brackett ldquoSurvival and growth of Liste-ria monocytogenes on lettuce as influenced by shredding chlo-rine treatment modified atmosphere packaging and tempera-turerdquo Journal of Food Science vol 55 no 3 pp 755ndash758 1990

[49] L Palou J L Smilanick CH Crisosto andMMonir ldquoEffect ofgaseous ozone exposure on the development of green and bluemolds on cold stored citrus fruitrdquo Plant Disease vol 85 no 6pp 632ndash638 2001

[50] LGiongo P Poncetta P Loretti and F Costa ldquoTexture profilingof blueberries (Vaccinium spp) during fruit development


ripening and storagerdquo Postharvest Biology and Technology vol76 pp 34ndash39 2013

[51] D A Marshall J M Spiers and S J Stringer ldquoBlueberrysplitting tendencies as predicted by fruit firmnessrdquoHortSciencevol 43 no 2 pp 567ndash570 2008

[52] I Escriche J A Serra M Gomez and M J Galotto ldquoEffect ofozone treatment and storage temperature on physicochemicalproperties of mushrooms (Agaris bisporus)rdquo Food Science andTechnology International vol 7 no 3 pp 251ndash258 2001

[53] M Larsen and C B Watkins ldquoFirmness and concentrations ofacetaldehyde ethyl acetate and ethanol in strawberries stored incontrolled and modified atmospheresrdquo Postharvest Biology andTechnology vol 5 no 1-2 pp 39ndash50 1995

[54] C B Watkins J E Manzano-Mendez J F Nock J Zhang andK E Maloney ldquoCultivar variation in response of strawberryfruit to high carbon dioxide treatmentsrdquo Journal of the Scienceof Food and Agriculture vol 79 no 6 pp 886ndash890 1999

[55] M Larsen and C B Watkins ldquoFirmness and aroma composi-tion of strawberries following short-term high carbon dioxidetreatmentsrdquo HortScience vol 30 pp 303ndash305 1995

[56] T Goto M Goto K Chachin and T Iwata ldquoThemechanism ofthe increase of firmness in strawberry fruit treated with 100CO2

rdquo Nippon Shokuhin Kagaku Kogaku Kaishi vol 43 no 10pp 1158ndash1162 1996

[57] F R Harker H J Elgar C B Watkins P J Jackson and I CHallett ldquoPhysical and mechanical changes in strawberry fruitafter high carbon dioxide treatmentsrdquo Postharvest Biology andTechnology vol 19 no 2 pp 139ndash146 2000

[58] C Pelayo S E Ebeler and A A Kader ldquoPostharvest life andflavor quality of three strawberry cultivars kept at 5∘C in air orair+20 kPaCO

2

rdquoPostharvest Biology andTechnology vol 27 no2 pp 171ndash183 2003

[59] P M Allan-Wojtas C F Forney S E Carbyn and K UNicholas ldquoMicrostructural indicators of quality-related charac-teristics of blueberries an integrated approachrdquo Lebensmittel-Wissenschaft amp Technologie vol 20 pp 23ndash32 2001

[60] P VMahajan andT KGoswami ldquoExtended storage life of litchifruit using controlled atmosphere and low temperaturerdquo Journalof Food Processing and Preservation vol 28 no 5 pp 388ndash4032004

[61] P Gunness O Kravchuk S M Nottingham B R DrsquoArcy andM J Gidley ldquoSensory analysis of individual strawberry fruitand comparison with instrumental analysisrdquo Postharvest Biol-ogy and Technology vol 52 no 2 pp 164ndash172 2009

[62] A Doslashving and F Mage ldquoMethods of testing strawberry fruitfirmnessrdquo Acta Agriculturae Scandinavica Section B Soil ampPlant Science vol 52 no 1 pp 43ndash51 2002

[63] J A Abbot R Lu B L Upchurch and R L Stroshine ldquoTech-nologies for nondestructive quality evaluation of fruits andvegetablesrdquo in Horticultural Reviews vol 20 pp 1ndash120 JohnWiley amp Sons 1997

[64] R L Jackman and D W Stanley ldquoPerspectives in the texturalevaluation of plant foodsrdquo Trends in Food Science and Technol-ogy vol 6 no 6 pp 187ndash194 1995

[65] Y Deng Y Wu and Y Li ldquoEffects of high O2

levels on post-harvest quality and shelf life of table grapes during long-termstoragerdquo European Food Research and Technology vol 221 no3-4 pp 392ndash397 2005

[66] V Chiabrando G Giacalone and L Rolle ldquoMechanical behav-iour and quality traits of highbush blueberry during posthar-vest storagerdquo Journal of the Science of Food and Agriculture vol89 no 6 pp 989ndash992 2009

[67] C F Forney U K G N Kumudini and M A Jordan ldquo Effectof postharvest storage conditions on firmness of lsquoBurlingtonrsquoblueberry fruitrdquo in Proceedings of the 8th North AmericanBlueberry Research and Extension Workers Conference pp 227ndash232 1998

[68] J M Smagula W Litten Y Chen and S Dunham ldquoVariationof fruit set and fruit characteristics of wild lowbush blueberries(Vaccinium angustifolium alt) in a managed fieldrdquo Acta Horti-culturae vol 446 pp 109ndash115 1997

[69] J Khazaei and D D Mann ldquoEffects of temperature and loadingcharacteristics on mechanical and stressmdashrelaxation propertiesof sea buckthorn berries Part 1 Compression testsrdquoAgriculturalEngineering International CIGR Journal of Scientific Researchand Development vol 6 pp 3ndash11 2004

[70] DWDonahue PWBenoit B J Lagasse andWR Buss ldquoCon-sumer and instrumental evaluation of Maine wild blueberriesfor the fresh pack marketrdquo Postharvest Biology and Technologyvol 19 no 3 pp 221ndash228 2000

[71] B H Barrit and L C Torre ldquoFruit firmness measurements inred raspberryrdquo HortScience vol 15 pp 38ndash39 1980

[72] M C Bourne ldquoTextural evaluation of horticultural cropsrdquoHortScience vol 15 pp 51ndash56 1980

[73] Z Bernstein and I Lustig ldquoA newmethod of firmness measure-ment of grape berries and other juicy fruitsrdquo Vitis vol 20 pp15ndash21 1981

[74] F Mencarelli R Massantini L Lanzarotta and R BotondildquoAccurate detection of firmness and colour changes in the pack-ing of table grapes with paper dividersrdquo Journal of HorticulturalScience vol 69 no 2 pp 299ndash304 1994

[75] F Duprat M Grotte E Pietri and D Loonis ldquoThe acousticimpulse response method for measuring the overall firmness offruitrdquo Journal of Agricultural Engineering Research vol 66 no4 pp 251ndash259 1997

[76] P Barreiro andMRuiz-Altisent ldquoInstrumentacion de la calidaden frutas y hortalizas frescasrdquo Horticultura vol 8 pp 14ndash202000

[77] S Khanizadeh J DeEII J Cousineau and I Lagrave ldquoCom-parison of three methods to evaluate fruit firmness in advancedstrawberry selectionsrdquoActaHorticulturae vol 517 pp 463ndash4652000

[78] J L Silva E Marroquin F B Matta J O Garner Jr and JStojanovic ldquoPhysicochemical carbohydrate and sensory char-acteristics of highbush and rabbiteye blueberry cultivarsrdquo Jour-nal of the Science of Food andAgriculture vol 85 no 11 pp 1815ndash1821 2005

[79] J E Swift Effects of frozen storage and harvest time on the tex-tural and sensory properties of rabbiteye blueberries (Vacciniumvirgatum Aiton) [MS thesis] NCSU Raleigh NC USA 2010

[80] A A Kader ldquoPostharvest handlingrdquo inThe Biology of Horticul-ture An Introductory Textbook J E Preece and P E Read Edspp 353ndash377 Wiley New York NY USA 1993

[81] E Das G C Gurakan and A Bayindirli ldquoEffect of controlledatmosphere storage modified atmosphere packaging and gase-ous ozone treatment on the survival of SalmonellaEnteritidis oncherry tomatoesrdquo FoodMicrobiology vol 23 no 5 pp 430ndash4382006

[82] X Fan K J B Sokorai J Engemann J B Gurtler and YLiu ldquoInactivation ofListeria innocua SalmonellaTyphimuriumand Escherichia coli O157H7 on surface and stem scar areasof tomatoes using in-package ozonationrdquo Journal of FoodProtection vol 75 no 9 pp 1611ndash1618 2012


[83] F M Basiouny and Y Chen ldquoEffects of harvest date maturityand storage intervals on postharvest quality of rabbiteye blue-berry (Vaccinium ashei Reade)rdquo Proceedings of the Florida StateHorticultural Society vol 101 pp 281ndash284 1988

[84] M J Ceponis and R A Cappellini ldquoReducing decay in freshblueberries with controlled atmospheresrdquo HortScience vol 20pp 228ndash229 1985

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology


Molecular Biology International

GenomicsInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


BioinformaticsAdvances in

Marine BiologyJournal of



Signal TransductionJournal of


BioMed Research International

Evolutionary BiologyInternational Journal of



Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Genetics Research International


Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


Mitcham and Mitchell [12] grey mold rot and other decayorganisms can be minimized by using gas concentrationsof 15 to 20 carbon dioxide and 5 to 10 oxygen whichwill also decrease respiration and softening rates of shippedblueberries raspberries and blackberries thus prolongingpostharvest life

Ozone (O3) is a strong antimicrobial agent with variety of

applications in the food industry [13] Ozone was designatedas generally recognized as safe (GRAS) in 1982 by theUS Food and Drug Administration (FDA) for use as adisinfectant or sanitizer in the gas or liquid phase on food (21CFR Part 173) and for direct contact use as an antimicrobialfor treatment storage and processing on diverse foodsincluding raw and minimally processed fruits and vegetables[14] Ozone decomposes rapidly into oxygen without leavingresidues [15] and its postharvest applications have increased[16]Moreover its use in cold rooms helps reduce the ethylene(C2H4) level in air extending the storage life of fruits and

vegetables such as apples and oranges [17] Other studies haveproven inhibition of spoilage microorganisms and shelf lifeextension using O

3in bananas [18] potatoes onions and

beetroot [19] tomatoes andmandarins [20] blackberries [21]lettuce and carrots [22] and strawberries [23]

However other studies have found ozone to be ineffectiveto control spoilage on apples blueberries green beans musk-melons peaches and strawberries [24] Furthermore applescantaloupes cranberries and corn kernels showed increaseddecay and spoilage contamination when ozone was used onthem [25ndash27]

According to Palou et al [28] 03 ppm O3on peaches

and table grapes did not delay decay however grey mold wasinhibited on grapes Perez et al [23] found 035 ppmO

3ineffi-

cient to prevent fungal decay in addition to negative effects onthe sensory properties of strawberries Although highO

3may

be necessary for an effective elimination of microorganismsthis may alter negatively the sensory attributes of fresh fruit[29]

The present study evaluated shelf life extension and qual-ity preservation of fresh blueberries packaged under differentatmosphere conditions (Air controlled atmosphere storage(CAS) 5 O

2 15 CO

2 80 N

2 or Ozone) and tempera-

ture storage (4∘C or 12∘C) for 10 days

2 Materials and Methods

21 Fruit Samples The trial was carried out during the sum-mer of 2012 using highbush blueberries (Vaccinium corym-bosum L cv Ozark Blue) that were hand harvested fromthe commercial planting Three Birds Berry Farm locatedin Blacksburg VA Two replications were conducted eachconsisting of fruit harvested at two different dates Only fullycolored developed fruit without defects was selected on avisual basis

22 Fruit Storage After harvest collection samples werestored in a cooler (4ndash8∘C) and transported to the FoodScience and Technology Building at Virginia Tech Samplesconsisted of fifty blueberries stored in 44 oz PET perforated

retail clamshell boxes (HighlandCorporationMulberry FL)which were placed in a dessicator cabinet and incubated atdifferent temperatures (4∘C or 12∘C) and different atmo-sphere conditions (Air as a control (21 O

2and 003

CO2) 5 O

2 15 CO

2 80 N

2 Ozone) Ten samples were

analyzed on days 0 1 4 7 and 10 per storage temperature andatmosphere conditions

23 Controlled Atmosphere and Ozone Treatment Clearacrylic desiccator cabinets with exterior dimensions of1210158401015840W times 1210158401015840H times 1210158401015840D with gas ports including hygrometer(Cole-Parmer Lansing MI USA) were used to store fruit inclamshells inside an incubator (Precision IncubatorThermoScientific Waltham MA) and held at 4∘C or 12∘C with 90ndash95 relative humidity (RH) which was maintained placinga deionized water in an open sterilized petri dish inside thedesiccators Temperature and RHweremonitored by a sensor(Traceable JumboThermo-HumidityMeter Fisher ScientificPittsburgh PA)

For controlled atmosphere storage a certified standard-spec compressed gas tank (MID-Saint Louis SGL-MO) sup-plied an atmosphere of 5 O

2and 15 CO

2and balanced

with nitrogen (80) Gas concentrations were maintained byreflushing the cabinets aftermonitoring them two times a day(morning and late afternoon) using an O

2CO2gas analyzer

(O2CO2Check Point PBI-Dansensor Ringsted Denmark)

A corona discharge ozone generator (FreshFridge 20Refrigerator Air Purifier Model GH 2138 IonCare GandHIndustrial Ltd China) and a small air circulating fan wereinstalled in the chambers Ozone concentration in chamberswas monitored controlled and recorded continuously usingan ozone analyzer (Model ES-600 Ozone Solutions Inc IAUSA) and a Dell Latitude D830 computer as data logger(Dell Round Rock Texas) Ozone concentration mean andstandard deviation valueswere 40plusmn 18 ppm for 4∘Cand 25plusmn15 ppm at 12∘C A third chamber without an ozone generatorserved as the control (Air) Blueberries were exposed tocontrolled atmosphere and ozone in these chambers for atotal of 10 days

24 Weight Loss Each clamshell with fifty blueberries wasweighed after harvest and the reweighed after 1 4 7 and 10days of storage Weight was recorded using a scale with anaccuracy of 001 g and expressed as accumulated weight losspercentage per unit time

25 Yeast and Molds Yeast and Molds Petrifilm (3M Micro-biology Products St Paul MN) pouches were stored uno-pened at 4∘C To aseptically prepare 1 10 dilutions 10 g ofblueberries was added to a stomacher bag with 90mL ofsterile 01 peptone water (Difco Becton Dickinson SparksMD) Samples were blended and stomached for 120 seconds(AES Laboratoire Easy Mix Microbiology InternationalCombourg France) serially diluted and plated on Yeastand Mold Petrifilm in duplicate Plates were incubated inhorizontal position clear side up in stacks not exceeding 20units for 3 days at room temperature 20ndash25∘C







2+




00

05

10

15

20

25

30

1 4 7 10 1 4 7 10

Wei

ght l

oss (

)

Time (day)

AirCAS

a a a a a a a b ab

4∘C 12


O3



3







2and O







2and rich CO










2[40] Na



3stimulated


3decreases




2consumed







3and CAS treatments










3






3treatment reduced














2levels [55 56]The





2during storage














4 Conclusion


3treatments


3




3and




Acknowledgment


References

















































2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology







2+




00

05

10

15

20

25

30

1 4 7 10 1 4 7 10

Wei

ght l

oss (

)

Time (day)

AirCAS

a a a a a a a b ab

4∘C 12


O3



3







2and O







2and rich CO










2[40] Na



3stimulated


3decreases




2consumed







3and CAS treatments










3






3treatment reduced














2levels [55 56]The





2during storage














4 Conclusion


3treatments


3




3and




Acknowledgment


References

















































2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology






2[40] Na



3stimulated


3decreases




2consumed







3and CAS treatments










3






3treatment reduced














2levels [55 56]The





2during storage














4 Conclusion


3treatments


3




3and




Acknowledgment


References

















































2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology












2levels [55 56]The





2during storage














4 Conclusion


3treatments


3




3and




Acknowledgment


References

















































2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology







4 Conclusion


3treatments


3




3and




Acknowledgment


References

















































2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology





























2

and CO2

















2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology












2





































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology











Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

research article shelf life determination of fresh blueberries...

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