Efficacy of Wahasing and Sanitizing Metohods

UDC 613.262:614.31 reviewISSN 1330-9862

(FTB-1110)

Efficacy of Washing and Sanitizing Methods for Disinfection

of Fresh Fruit and Vegetable Products

Gerald M. Sapers

U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center,600 East Mermaid Lane, Wyndmoor, PA 19038, U.S.A.

Received: October 10, 2001Accepted: November 8, 2001

Summary

In recent years, as a consequence of the increasing number of produce-related outbre-aks of food-borne illness, greater attention has been given to interventions that kill or re-move human pathogens on fresh produce. A key goal of washing and sanitizing treat-ments, therefore, is removal or inactivation of such pathogens. However, published in-formation suggests that conventional washing and sanitizing methods, even using newersanitizing agents, are not capable of reducing microbial populations by more than 90 or 99 %,although greater efficacy is required to assure product safety. The response of microorga-nisms to washing and sanitizing treatments will depend in part on the conditions of con-tamination that affect attachment and survival on produce surfaces. Major factors limitingdecontamination efficacy include strength and rapidity of microbial attachment, inaccessi-bility of attachment sites, attachment and growth in cuts and punctures, internalization ofmicrobial contaminants within plant tissues, and biofilm formation. The performance ofconventional produce washing equipment and washing and sanitizing agents in reducingmicrobial loads is examined. Recent improvements in washing and sanitizing technologyare described. New approaches to washing and sanitizing produce that overcome the bar-riers limiting human pathogen detachment and inactivation are examined.

Key words: fruit and vegetable products, washing and sanitizing treatments, pathogene de-tachment and inactivation

Introduction

In recent years, producers, regulatory agencies, andthe public have become increasingly concerned aboutthe microbiological safety of fruits and vegetables. Pro-duce-related outbreaks of foodborne illness are morenumerous. Outbreaks have been attributed to sproutedseeds, leafy vegetables, tomatoes, melons, berries, andunpasteurized juices (1). Escherichia coli O157:H7, Salmo-nella species, Listeria monocytogenes, Shigella species,

Cyclospora cayetanensis, Hepatitis A virus, and Norwalk--like virus have been the causative organisms (1,2). In-creasing attention is being given to the need for bettermethods to disinfect fresh produce containing humanpathogens.

Most processors and consumers have assumed thatwashing and sanitizing fresh fruits and vegetables willreduce the microbial load. However, published efficacy

305G. M. SAPERS: Efficacy of Washing and Sanitizing Methods, Food Technol. Biotechnol. 39 (4) 305–311 (2001)

Direct inquiries to Dr. Gerald M. Sapers: USDA, ARS, ERRC, 600 East Mermaid Lane, Wyndmoor, PA. Phone: 215-233-6417; Fax:215-233-6406; Email: [email protected].

Mention of brand or firm names does not constitute an endorsement by the U.S. Department of Agriculture over others of a similarnature not mentioned.

data indicate that these conventional, time-honoredmethods are not capable of reducing microbial popula-tions on produce by more than 90 to 99 % (3,4). Whilesuch population reductions are useful and not to be mi-nimized, they are insufficient to assure microbiologicalsafety. It must be realized that conventional washingtechnology was developed primarily to remove soil fromproduce, not microorganisms, and even with newer san-itizing agents such as chlorine dioxide, ozone, and pe-roxyacetic acid, improvements in efficacy have been in-cremental. Because of these limitations, it is preferable,wherever possible, to avoid microbial contamination offruits and vegetables by following good agricultural andmanufacturing practices rather than depend on decon-tamination technologies.

Microbiologists generally express population reduc-tion data as logarithms rather than as percentages toavoid calculations with very large numbers, such as areusually encountered with microbial populations in theenvironment and on foods. In this article, population re-duction data will be expressed as log10(CFU/g) valueswhere log reductions of 1, 2, 3, 4 and 5 are equivalent topercentage reductions of 90, 99, 99.9, 99.99, and 99.999%, respectively.

In order to improve the efficacy of pathogen reduc-tion by washing and sanitizing produce, one needs tounderstand and overcome the mechanisms by which at-tached bacteria resist detachment or inactivation. Thisrequires knowledge of the physiological state of attach-ed bacteria, their attachment sites, their interactionswith the plant surface and other microorganisms, andtheir sensitivity to antimicrobial agents. In developingnew or improved washing and sanitizing treatments forfruits and vegetables, one must also take into accountcompatibility of treatments with commercial practices,treatment cost, absence of treatment-induced adverse ef-fects on product quality, the need for regulatory appro-val, and the need for consumer acceptance. In this pa-per, these issues will be examined, and several promis-ing new approaches to produce decontamination will beidentified.

Factors Limiting the Efficacy of Washing

Contamination conditions

Contamination of produce with human pathogensmay occur at any point during production, harvesting,packing, processing, distribution, or marketing whereexposure to human or animal feces is possible. Gen-erally, the earlier in this sequence of events contamina-tion occurs, the more difficult it is to disinfect the prod-uct. This is a consequence of the increasing likelihoodthat the contaminating bacteria have become firmly at-tached in inaccessible locations, incorporated into bio-films, or even internalized within the fruit or vegetableinterior. Of particular concern is exposure of produce tocontaminated irrigation or spray make-up water (5), wind-blown dust from a nearby pasture or feedlot (6), and in-sects (7–9) or birds (10) that may be vectors of humanpathogens. These conditions favor microbial internaliza-tion or attachment in inaccessible sites such as the calyxor stem areas of apples and skin punctures. The moist

environment and nutrient availability prevailing in the-se sites also might favor biofilm formation. Inaccessibil-ity, internalization and biofilm formation would impedeor preclude disinfection of contaminated produce by ap-plication of washing or sanitizing agents.

Interval between contamination and washing

We have found that the effectiveness of washingmay depend on the time interval between the contami-nation event and washing. Data obtained with apples,artificially inoculated with E. coli and then held for vari-ous times before washing with water, indicate that aninterval of 30 min between inoculation and washing re-sulted in a 1 log population reduction. However, after24 hours, essentially all of the bacteria were firmly at-tached and could not be removed by washing (11). Whencantaloupes, inoculated with a non-pathogenic E. coli orSalmonella stanley, were washed with 1000 ppm chlorine(added as sodium hypochlorite), or 5 % hydrogen per-oxide immediately after inoculation, population reduc-tions exceeding 3 logs were obtained. Washing with the-se anti-microbial agents 72 hours after inoculation wasmuch less effective in reducing the bacterial popula-tions, resulting in population reductions less than 1 logunit for S. stanley (12,13). Liao and Cooke (14) showedthat the initial attachment of Salmonella to cut surfaces ofpepper disks was very rapid.

Attachment in inaccessible sites

When bacteria attach to the surfaces of fruits andvegetables, they tend to locate in pores, indentations orother natural irregularities on the intact surface wherethere are protected binding sites (15). Bacteria also at-tach at cut surfaces (14,16) or in punctures and cracks inthe commodity surface (17). We found greater attach-ment of E. coli in the calyx and stem areas of inoculatedapples than elsewhere on the fruit, and greater survivalafter washing in these areas than elsewhere on the applesurface (Table 1) (11). Bacteria in these locations escapecontact with washing or sanitizing agents. Riordan et al.(5) reported high levels of bacteria in the calyx and stemareas of naturally contaminated apples.

Salmonella chester survived washing to a much greaterextent when attached at cut surfaces of apple and greenpepper disks than on unbroken external surfaces (14,18).These results are a matter of concern to the fresh-cut in-dustry since their products provide extensive cut sur-

306 G. M. SAPERS: Efficacy of Washing and Sanitizing Methods, Food Technol. Biotechnol. 39 (4) 305–311 (2001)

Table 1. Distribution of E. coli (ATCC 25922) on surface of ino-culated apples before and after washing with 5 % H2O2 at 50 °Ca

LocationE. coli log(CFU/cm2)b

Inoculated Washedc

Skin at calyx end of core 6.79d 4.46d

Skin on stem end of core 5.61d 4.89d

Skin except removedcalyx and stem portions

4.37e 1.63e

a Adapted from Sapers et al. (11).b Based on calculated surface area of skin.c Washed 72 hours after inoculation; washed for 1 min in 5 %

H2O2 at 50 °C.d–e Within the same column, means with no letter in common

are significantly different (p<0.05) by Bonferroni LSD.

faces for bacterial attachment, making them especiallyvulnerable to contamination.

A number of commodities (i.e., apples, pears, cher-ries, grapes, zucchini squash, potatoes, carrots, and let-tuce) often have punctures, cuts or splits that could besites for bacterial attachment. Growth of E. coli withinpunctures was demonstrated in artificially inoculated applesin spite of the fruit’s high acidity (11). Apparently, thebacteria could create a more hospitable microenviron-ment within the puncture. Janisiewicz et al. (7,19) alsoreported growth of E. coli in wounds on apples. Ourdata (Table 2) indicate that when the bacteria have be-come established within a puncture, they are very diffi-cult to kill (11).

Biofilms

Once attached, bacteria might become incorporatedinto a biofilm, an extracellular polysaccharide matrix thatholds the cells together and glues them to the commod-ity surface (20–22). In this state, the bacteria are moreresistant to detachment or inactivation by washing treat-ments. Human pathogens such as E. coli O157:H7, Sal-monella spp. and L. monocytogenes as well as other bac-teria such as Pseudomonas and Erwinia spp. are capable offorming biofilms (23). The presence of human pathogensin biofilms on fruits and vegetables and on processingequipment would greatly limit the ability to disinfectsuch produce (20,22,24).

Internalization of bacteria within produce

Internalization of bacteria within certain fruits andvegetables can occur during packing or processing (25–27). When a warm commodity that has internal air spa-ces is placed in colder water, perhaps in a packing plantdump tank or flume, the internal gas cools and con-tracts. This creates a partial vacuum that will allow wa-ter and any microorganisms contained therein to bedrawn in or »infiltrated« through pores, channels, orpunctures into the commodity (25,27). Infiltration of Er-winia carotovora subsp. carotovora, a spoilage organism,and Salmonella montevideo, a human pathogen, has beendemonstrated in tomatoes (25,28). Internalization also

can occur naturally due to contamination during flower-ing or fruit development (29). Internalization of E. coliO157:H7 has been reported in lettuce (15,16) and radishsprouts (30), while other bacterial species have been de-tected within cucumbers and tomatoes (29,31). We havedetected coliform bacteria but no human pathogens in-ternalized within the core of apples that were exposedto dust from an adjacent pasture (6). As stated previ-ously, internalization of human pathogens within pro-duce would preclude effective disinfection by washingand sanitizing treatments.

Efficacy of Conventional Washing Technology

Washing equipment

Various types of washers are available for commod-ities such as apples and potatoes, leafy vegetables, broc-coli, root vegetables, corn, etc. These include brushwashers, reel washers, pressure washers, hydro air agi-tation wash tanks, and immersion pipeline washers.These units were designed to remove soils from pro-duce, and not much is known about their ability to re-move or inactivate bacterial contaminants.

To obtain such information, we conducted a seriesof washing trials with artificially contaminated applesusing commercial U-bed and flat-bed brush washers. Inthese trials the fruit was washed with hot or cold water,chlorine solutions, acidic detergent solutions, trisodiumphosphate solutions, and dilute hydrogen peroxide, anexperimental sanitizing agent (Table 3). In the laborato-ry, some of these treatments were capable of reducingbacterial populations on inoculated apples by 2–3 logunits. However, when the same treatments were appliedusing commercial washers, population reductions wereless than 1 log unit (32,33). This lack of efficacy was duein part to deficiencies in equipment design resulting ininsufficient exposure of inoculated apple surfaces to thewashing agents, especially in the inaccessible calyx andstem areas where contact with brushes was minimal.Bacterial adherence to apple surfaces, biofilm formationand internalization also might have contributed to thepoor results, as discussed previously.


Table 2. Efficacy of H2O2-based washes for decontamination ofpunctured Golden Delicious apples inoculated with E. coli(ATCC 25922)a

Treatmentb log(CFU/g reduction)c

No puncture Puncturedd

5 % H2O2 2.34f 0.58g

1 % APL-Kleen® 245; 5 % H2O2e 2.83f 1.62f

a From Sapers et al. (11).b 1 min wash at 50 °C.c Means of duplicate trials; based on control populations of

4.88 log(CFU/g).d 1-cm deep puncture made with 3.7 mm diam. sterile nail on

top surface of apple 2–3 cm from stem.e Two-stage treatment: 1 % APL-Kleen® 245 followed by

5 % H2O2.f–g Within the same column, means with no letters in common

are significantly different (p<0.05) by Bonferroni LSD.

Table 3. Decontamination of apples inoculated with E. coli(Strain K12) with sanitizing washes applied in a flat-bed brushwasher a

Washtreatment

Temp.°C

E. coli log(CFU/g)b

Beforedump tank

Afterdump tank

Afterbrush water

Water 20 5.49 ± 0.09 4.92 ± 0.37 4.81 ± 0.26

50 5.40 ± 0.09 5.04 ± 0.16 4.59 ± 0.08

200 ppm Cl2 20 5.87 ± 0.07 5.45 ± 0.05 5.64 ± 0.23

8 % Na3PO4 20 5.49 ± 0.09 5.02 ± 0.43 4.98 ± 0.02

50 5.49 ± 0.09 5.02 ± 0.08 4.75 ± 0.45

1 % acidic deterg.c 50 5.87 ± 0.07 5.49 ± 0.03 5.42 ± 0.50

5 % H2O2 20 5.87 ± 0.07 5.46 ± 0.40 5.27 ± 0.09

50 5.87 ± 0.07 5.54 ± 0.31 5.49 ± 0.10

a Adapted from Annous et al. (33).b Mean of 4 determinations ± standard deviation.c APL Keen 245 (Elf Atochem North America, Inc., Decco Dept.,

Monrovia, Calif., U.S.A.).

Washing and sanitizing agentsfor fruits and vegetables

A number of washing and sanitizing agents havebeen approved for fruits and vegetables, and some ofthese have been evaluated in laboratory-scale investiga-tions. These studies generally apply such treatments byimmersion of an artificially contaminated commodity inan aqueous solution for a prescribed time. The results ofsuch studies vary widely, depending on the method ofsample inoculation, the choice of test organism, the timeinterval between inoculation and treatment, treatmentconditions (i.e., temperature, degree of agitation), andthe method of recovering and enumerating the test or-ganisms. However, some insights into means of improv-ing treatment efficacy can be gleaned from these studies.

Chlorine. Chlorine is the most widely used sanitiz-ing agent for fresh produce (3,4). Published data indi-cate that at permitted concentrations, population reduc-tions on produce surfaces will be within the range of1–2 log units (28,34–38). This is due in part to the rapidbreakdown of chlorine in the presence of organic matterin soil and on product surfaces. Some improvement inefficacy can be obtained by adding a wetting agent (39).Another means of improving treatment efficacy is tomonitor the oxidation-reduction potential or ORP (tar-get value of 650 mV) and pH (about 6.5) of the processwater and to use these values to control hypochloriteaddition and pH adjustment (40).

Use of electrolyzed water as a sanitizing agent forproduce has received a lot of recent attention. This is aspecial case of chlorination (41). Electrolysis of watercontaining a small amount of sodium chloride generatesa highly acidic hypochlorous acid solution containing10–100 ppm available chlorine. The results of electroly-zed water treatments have been mixed. Park et al. (42)reported population reductions on lettuce leaves exceed-ing 2.49 log units for E. coli O157:H7 and L. monocytoge-nes. Horton et al. (43) reported population reductions ofE. coli O157:H7 on apples of 3.7–4.6 log units, but Izumi(42) could demonstrate only a 1 log unit reduction in themicrobial population on fresh-cut vegetables.

The reaction of chlorine with organic residues canresult in the formation of potentially mutagenic or carci-nogenic reaction products (44,45). This is a cause for con-cern since some restrictions in the use of chlorine mighteventually be implemented by regulatory agencies. The-refore, a number of alternatives to chlorine have been ex-amined, and some are in commercial use.

Detergent formulations and other commercial pro-duce washes. Numerous commercial washing formula-tions for fresh produce are available, including surfac-tant solutions, combinations of surfactants with organicor mineral acids, and alkaline washes. In tests with arti-ficially inoculated apples, we found that these formula-tions were generally similar to chlorine, achieving a 1–2log units reduction in the E. coli population (38). Popula-tion reductions were about 0.5 log unit greater whentreatments were applied at 50 °C instead of at ambienttemperature. Wright et al. (46) reported similar popula-tion reductions in apples inoculated with E. coli O157:H7 with a commercial phosphoric acid fruit wash andwith a 200 ppm hypochlorite wash.

Alternative sanitizing agents. Ozone is one of sev-eral new sanitizing agents for produce introduced in re-cent years and approved by the U.S. Food and Drug Ad-ministration as alternatives to chlorine (47–51). Ozone iseffective in reducing microbial populations in wash andflume (52–53). However, ozone treatment was ineffecti-ve in reducing decay of pears (54), and Kim et al. (50)obtained less than a 1 log unit reduction in lettuce inoc-ulated with Pseudomonas fluorescens.

Chlorine dioxide can reduce microbial populationsin dump tank and wash water. However, tests with cu-cumbers resulted in less than a 90 % (1 log unit) popula-tion reduction on product surfaces (55). A chlorine diox-ide product, Oxine, applied at the recommended con-centration, was ineffective in reducing the population ofE. coli O157:H7 on inoculated apples (56).

Peroxyacetic acid (or peracetic acid, actually anequilibrium mixture of the peroxy compound, hydrogenperoxide, and acetic acid) has been recommended fortreatment of process water (57,58). However, populationreductions for aerobic bacteria, coliforms, and yeasts andmolds on fresh-cut celery, cabbage and potatoes, treatedwith 80 ppm peroxyacetic acid (the recommended con-centration), were less than 1.5 log units (59). Wright etal. (46) obtained a 2 log units reduction in apples inocu-lated with E. coli O157:H7 using 80 ppm peroxyaceticacid, but the interval between inoculation and treatmentwas only 30 min. In contrast, in a similar apple study,Wisniewsky et al. (56) obtained less than a 1 log unit re-duction at the same peracetic acid concentration, but theinterval between inoculation and treatment was 24hours. We obtained comparable results at this concen-tration using apples inoculated with a non-pathogenicE. coli and had to increase the concentration to 1000 ppmin order to obtain a 2 log units reduction (38).

These reports clearly show that the commerciallyavailable alternatives to chlorine, like chlorine, are lim-ited in their ability to kill bacteria attached to producesurfaces when realistic inoculation and treatment condi-tions are used. In order to exceed the apparent popula-tion reduction »ceiling« of 1–2 log units, more effectivesanitizing agents and application methods must be de-veloped that provide better contact between the sanitiz-ing agent and microbial attachment sites on producesurfaces. It should be noted however, that chlorine andthe approved chlorine alternatives are highly effectiveagainst microorganisms suspended in water, and so areadded to hydrocooling, flume and wash water to reducemicrobial populations in recirculating water systems.Thus, these sanitizers play an important role in prevent-ing or reducing the risk of produce cross-contamination.

New Technology for Disinfection of Produce

Hydrogen peroxide as a sanitizing agent

We have had extensive experience with hydrogenperoxide and believe that it shows potential as a highlyeffective sanitizing agent for produce. Hydrogen perox-ide vapor treatments have been investigated for controlof post-harvest decay in grapes (59), melons (60) andother commodities, and to disinfect prunes (61). How-ever, such treatments require lengthy application times


(i.e., 15–60 min) and can cause injury to some commodi-ties such as mushrooms, raspberries and strawberries(62). Dilute hydrogen peroxide solutions were shown tobe effective in washing mushrooms (63–65), controllingpostharvest decay of vegetables (65), extending the shelf--life of fresh-cut vegetables and melons (62), and decon-taminating apples containing E. coli (11,38). Recent studiesin our laboratory with inoculated apples and cantalou-pes have shown that 5 % hydrogen peroxide solutionscan achieve log units reductions of 3 or higher when ap-plied by full immersion of the commodity in the solu-tion with vigorous agitation and at a temperature of 50–60 °C for apples and 70–80 °C for cantaloupe (67).

Hydrogen peroxide is Generally Recognized as Safe(GRAS) for some food applications but has not yet beenapproved as an anti-microbial wash for produce. Hy-drogen peroxide produces no residue since it is rapidlydecomposed by catalase, an enzyme found throughoutthe plant kingdom, to water and oxygen. However, hy-drogen peroxide is injurious to some commodities, caus-ing browning of apple skin at temperatures greater than60 °C and bleaching of anthocyanins in mechanicallydamaged berries (62).

Novel means of applying sanitizing agents

Vacuum infiltration. Previously, we investigatedvacuum infiltration as a means of increasing uptake ofbrowning inhibitors by cut apples, thereby improvingtreatment efficacy (68). The same technology was ap-plied to treatment of whole apples with hydrogen per-oxide or chlorine to improve contact between the sani-tizing agent and bacteria attached in inaccessible siteson the apple surface by removing gas or liquid barriersthat block penetration of the sanitizing agent. Applica-tion of a 5 % hydrogen peroxide solution to inoculatedapples under vacuum resulted in a 4–5 log units reduc-tion in the E. coli population in the calyx area, and a 4log units reduction, based on the total weight of thetreated apples (69). Vacuum infiltration of hydrogen pe-roxide appears to be non-injurious to apples, leaves noperoxide residue, and might be suitable for fresh marketapples or prior to fresh-cut processing.

Vapor-phase treatments. Application of anti-micro-bial agents in the vapor phase might be another meansof reaching microbial contaminants attached in inacces-sible sites. Chlorine dioxide vapor-phase disinfection ofcut green pepper, inoculated with E. coli O157:H7achieved a 6.45 log units population reduction (70). Ace-tic acid vapor treatment of cabbage, mung bean seeds,and grapes reduced microbial populations and prevent-ed decay (71–74). In our laboratory, an E. coli populationreduction exceeding 3 log units was obtained in inocu-lated apples treated with hot acetic acid vapor, appliedin multiple vacuum/pressure cycles (69). However, thetreated apples showed browning, indicative of injuryduring storage following treatment. Our research on thevapor-phase application of volatile anti-microbial agentsis continuing.

Surface pasteurization. Application of hot water orstream to the surface of fresh fruits and vegetables

might be used to pasteurize product surfaces providedthat heat transfer into subsurface or inaccessible micro-bial attachment sites was sufficient. However, the feasi-bility of surface pasteurization would depend on the ab-sence of heat injury (altered flavor, color, texture orstorage stability) at the required exposure times andtemperatures. We carried out studies with cantaloupe todetermine whether immersion in hot water could pas-teurize the product surface without causing injury. Thecantaloupes tolerated exposure to water or 5 % hydro-gen peroxide at 80 °C for 3 min with no indication of in-jury initially or after storage at 4 °C for 26 days (75). Im-mersion of cantaloupe, inoculated with E. coli or Salmonellastanley, in 5 % hydrogen peroxide at 80 °C for 3 minutesresulted in at least a 4 log units population reduction.These results indicate that surface pasteurization of can-taloupes with hydrogen peroxide solutions is possibleand that this treatment would preclude transfer of hu-man pathogens from the rind to the flesh during fresh--cut processing that would result in contamination ofthe product (75).

Conclusions

Washing and sanitizing treatment can play an im-portant role in reducing microbial populations on freshfruits and vegetables intended for fresh market or fresh--cut processing, thereby improving product quality andsafety. Conventional washing and sanitizing agents typ-ically achieve 1–2 log units reductions in microbial pop-ulations under laboratory conditions; reductions can besubstantially smaller with some commercial producewashing systems. Such reductions are not sufficient toassure microbiological safety. Among the factors limit-ing efficacy of conventional washing and sanitizingtreatments are bacterial adherence to produce surfaces,bacterial attachment in inaccessible sites, formation ofresistant biofilms, and internalization of microorganismswithin commodities. Additionally, conventional washingequipment may not permit sufficient contact betweenattached bacteria on produce surfaces and the washingand sanitizing agents and/or brushes. While incremen-tal improvements can be made in sanitizer formulationsand washer design, these are unlikely to greatly increaseefficacy of washing and sanitizing treatments in decon-taminating produce.

New washing technologies using sanitizing agentsof greater lethality are needed to contact and kill micro-organisms that survive conventional washing and sani-tizing methods. Such technologies must not only be su-perior in efficacy; they must also be approved by regu-latory agencies, safe to apply, compatible with existingindustry practices, and affordable. Favorable resultshave been obtained with hydrogen peroxide, applied asa washes or by vacuum infiltration or as a medium forsurface pasteurization. Vapor-phase application of anti-microbial agents also shows promise. Commercializa-tion of such innovations might bring about large impro-vements in the microbiological quality and safety offresh and fresh-cut fruits and vegetables.


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U~inkovitost pranja i sanitacijski postupci

za dezinfekciju svjeèg vo}a i povr}a

Saètak

Posljednjih godina, kao posljedica pove}anog broja oboljenja prouzro~enih namirnica-ma, sve se ve}a pa`nja pridaje postupcima za uni{tavanje ili uklanjanje ljudskih patogenasa svjeìh proizvoda. Stoga je glavna svrha postupka pranja i sanitacije uklanjanje ili inak-tivacija patogena. Do sada objavljeni radovi navode da uobi~ajeni postupci pranja i sanita-cije, koriste}i ~ak i najnovija sredstva za sanitaciju, ne mogu sniziti populaciju mikroorga-nizama za vi{e od 90 ili 99 %. Da bi se osigurala potpuna sigurnost proizvoda, potrebna jejo{ ve}a u~inkovitost. Uklanjanje mikroorganizama pranjem i postupcima sanitacije ovisit}e dijelom o uvjetima kontaminacije {to obuhva}aju u~vr{}ivanje i preìvljavanje na po-vr{ini proizvoda. Glavni su ~initelji koji ograni~avaju uspje{nost kontaminacije jakost i br-zina mikrobnog prijanjanja, nedostupnost mjestima pri~vr{}ivanja, rast u zasjecima i rupi-cama, ulazak mikrobnih one~i{}enja unutar tkiva biljaka i stvaranje biofilma. Ispitana jedjelotvornost konvencionalnih ure|aja za pranje proizvoda te sredstava za pranje i sanita-ciju i ustanovljen je postotak uni{tenja mikroorganizama. Opisana su najnovija pobolj{anjau postupcima pranja i sanitacije. Tako|er su opisani novi pristupi pranju i sanitaciji proiz-voda koji prelaze granice {to su ograni~avale uklanjanje i inaktivaciju ljudskih patogena.


Efficacy of Wahasing and Sanitizing Metohods

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