Methods for ascertaining the cleaning Performance of ... · IKW-AK automatic dishwashing detergents* Methods for ascertaining the cleaning Performance of dishwasher detergents (part

IKW-AK automatic dishwashing detergents*

Methods for ascertaining the cleaningPerformance of dishwasher detergents(part A)Keywords: Test method, automatic dishwashing detergent,

!KW (Association of German Detergent Manufactures e V /Industrieverband Körperpflege und Waschmittel e.V.)

» Releasing soil from the dishes8 Dispersing thesoil in the wash

solution8 Complexing residual water hardness

and hardness iohs from foodresidues

• Maximizing gentle treatment ofthe dishes.

Because of this complexity, dishwash-er detergents are generally composedof up to five basic ingredients:

Alkalinity carriersComplexing agentsBleaching componentsBio-agents (enzymes)Wetting agents.

Until 1990, all the detergents availableon the market had similar composi-tions. They belonged to the group ofconventional classical powders listedin Table 1. The interaction of the alka-linity carriers (metasilicate/sodium car-bonate), the builder system (phos-phate) and the bleach system (activechlorine carrier) yielded relatively sim-ilar wash results on the relevant typesof soil, with little difference betweenthe detergent types.Not until the compact detergents werelaunched on the market in 1990/91 didsignificant differentiation of the washprofiles manifest themselvesasaresultof the greater scope for formulationdesign. With the test methods avail-able at that time, e.g. with compara-tive consumers association tests, it wasnot always possible to adequatelyhighlight these differences.Until that time, the test methods em-ployed had been developed by analo-gy with studies to assess the wash per-formance of dishwashers and subse-

1. Introduction

The market for dishwasher detergentsis a growth market owing to the in-creasingly widespread use of dish-washers in the home. On the Europe-an level, the rate of growth is about5 % per year. Closely linked to this,dishwasher detergents also benefitstrongly from this growth. The marketfor these detergents was worth about1.4 billion DM in Europe in 1997.Mechanical dishwashing invariably in-volves a system of products. Threeproducts are required overall: deter-gent, rinse aid and regeneration salt.Of crucial importance to mechanicaldishwashing is the detergent. Themost important tasks that it has to per-form are:

The product's overall Performancemay be supplemented by such addi-tional components as silver protectionagents, bleach catalysts, or the like.Typical detergent compositions ac-cording to formulation type can beseen in Table 1.

Alkaline carriers Metasilicate/- 30 - 70DisilicateSodium carbonae 0-10

Sodium carbonate 0-40Sodium bicarbonateDisilicates j 0-40

Phosphate | >3oCitrat |Phosphonate j 0 -2

| Polycarboxylate | 0-5| • • - • - - . |

I Active oxygen carrier I 3-20l TAED | o -6| Mn-Accellerator

Surfactants I o - 4

l Enzymee ( <6• f " _ , - • • j

j Perfumes ] <n,5| Paraffin oil | <-]'j Silver protection agent | <1

<11

0-400-400-40

Complexing agents +dispersing agents Triphosphate

Polymeres15-400-10 >30

0-20-15

3-200-6

<1

0 - 4

<6

<0,5<1<1>11

Bleaches + activator/-accelerator Active chlorine 0 - 2

carrier

Wetting agents

Bio-agents

Auxiliaries

Surfactants 0 -2

Paraffin oil approx.

| p H 1 % |

Table 1 Typical detergent compositions

12-13

52SÖFW-Journal, 125. Jahrgang 11/99

r " ~ ~ ' - -i Soil types

Colored, bleachable soil

Practical examples

• Tea (3, 4, 5, 6)• Ketchup• Carrot juice• Curry, saffron etc.• Lipstick

• Burnt meat [13]• Burnt custard [13]• Burnt milk [13]• Burnt casseroles etc.

• Porridge(1, 10, 13)• Starchy sauces/gravies• Casseroles (pasta, rice, potatoes)• Remains of dough/batter, baked-on

residues

• Egg yolk (7, 8, 9)• Casseroles (cheese, meat, egg)

• Discriminating• Long storage life.

The methods chosen should be suchthat even powerful detergents are in-capable of completely releasing thesoil. This will allow the possibility ofdifferentiating between powerfulproducts at the top end of the scale.

Persistent, burnt soil

Dried, starchy soil(amylase-specific)

3. Review ofexisting methods

Dried, proteinaceous soil(protease-specific) First of all, methods already known or

discovered in literature searches werestudied and assessed.Theoverwhelmingmajorityofthetestmethods were developed by organiza-tions of dishwasher manufacturers incooperation with various detergentmanufacturers. These methods weredesigned to clearly define the efficien-cy of the dishwasher in terms of the ac-tion of the spraying arms and the f i l-ter System. A major aspect of this,namely the primary release of variousfood soil types from the surface of thedishes, is inadequately described bythese methods. The majority of the soiltypes employed are not persistentenough for an assessment of deter-gent action.In addition to these so-called dish-washer-specific methods, the more re-cent literature reports on enzyme-spe-cific soils (7, 8, 9). These methods havebeen developed by enzyme manufac-turers and supply information on am-ylase- and protease-specific soils. Nev-ertheless, no attempt at an integrateddescription that would permit an as-sessment of dishwasher detergentshas been made.The various test methods can be seenin Table 3.An assessment of the various testmethods described at that time is giv-en by the work group in Table 4.

Table 2 Classification of Food Soil

quently applied to the assessment ofdetergents. The most widespreadmethods are DIN 44990 (1) and IEC 436(2). However, both methods were de-veloped at a time when the new com-pact detergents containing enzymeshad notyetbecomeestablished onthemarket. Consequently, these methodsare often incapable of adequately re-f lecting the wash prof ile of such deter-gents. It therefore became necessaryto develop a system based on the ex-isting methods for a more comprehen-sive assessment of the wash perfor-mance of dishwasher detergents.In the middle of 1995, underthe aus-pices of the German Industrial Associ-ation of the Manufacturers of Toilet-ries and Detergents (IKW), a workgroup of mechanical dishwashing ex-perts was set up for this task and wasjoined by representatives of leadingEuropean test institutes and dishwash-er manufacturers.

2. Goal

The goal of the work group was to se-lect forms of soil from the field to en-able the wash profile yielded by thecomposition of the detergent in ques-tion to be determined.Food soil on domestic dishes can beroughly classified (Table 2).

The test soil types also have to satisfythe following criteria.6 Simple (to produce, without com-

plex apparatus)• Relevant to practical washing

experience• Reproducible

IEC 436 (2)

DIN 44990 (1)

prEN 50242(10)(CenelecTC59X)

UTE 73-176 (11)

ANS I/AH AMDW-1-1982(12)

Altenschöpfer (13)

Novo (7,8)

Genencor (9)

1981

1989

in Arbeit

1968

1982

1971

1993

1994

Mechanical dishwasher





Detergent

Enzymes

Enzymes

Internationa

D, A, I, E, F

EU

F, I

USA

D

Internationa

Internationa

4. Methodology andproposed results

The task of the work group was, eitherto select such soiling methods fromthose already known, which enabledas high a differentiation as possiblebetween different detergent formula-tions, or to adjust those methods ac-cordingly. Hence, the soils should be so

Table 3 Existing Test Methods to Determine Cleaning Performance of Dishwash-ing Machines and Detergents

SÖFW-Journal, 125. Jahrgang 11/9954

Practicalrelevance

+

+

Reproduci-bilitv

Effort i Discrimination Storaqe5. Experience with the

methods to dateIEC436DIN 44990UTE 73-176 |ÄHÄM"

ÄltenschöpferjNovo IGenencor |

+ = good

+/-+? Since the conditions for soil prepara-

tion in the course of both test serieswith the products »R„ R2, R3«, [EC A,and »R3, P3«, [EC A, (Table 6) as well aspure water for the base level werechanged several times, individual re-sults will not be presented, but the ex-perience gained from the tests will bedescribed.

5.1 Bleach specific stainsThe hypochlorite containing productsand the hypochlorite-free products ofthe type RrR3 could be sufficiently dif-ferentiated using the tea method. Nodifferences could be found betweenthese three detergents which werebased on the same bleach System, thesame alkalinity, and the same builderSystem. Inthe2ndcomparativetest, ad-vantages were found under the com-pact detergents for the products con-taining phosphate, P3. Using wateralone, only minor removal of tea stainswas observed.

Not so suitable in Europe in the opinionof dishwashermanufacturers

++

+++

+++

++

++

- = bad

Table 4 Assessment by the Working Group of Various Test Methods Described

persistent, thateven powerfultestfor-mulations combined with favourablewashing conditions do not achieve100 % cleaning efficiency.Washing the soils in purewatershouldonly result in a minor removal of soils,such that a wide ränge of differentia-tion is achieved. Since the known soilscould not meet these criteria in everycase, the working group also under-took new developments. Especially inthe case of starch containing soils thedevelopments have been built on theknowledge attained from the relevantliterature (15-22).Additionally, other described, but notcertified, methods were included inthe assessment (starch mixture accord-ingto IECSC59 A / W G II (14), milk inthe microwave according to CenelecTC59X(10).For the selection of the soils to be in-cluded in the test method, a f urther re-quirement was that each of the soilclasses described in Table 2 (bleach-able/coloured, persistent/burnt, driedstarch containing as well as dried pro-tein containing) should be represent-ed by at least one Single soil. The fol-lowing 8 single soils in Table 5 finallyproved to be suitable to fulfil the re-quired criteria.The storage stability of the soils underlaboratory conditions is at least 14days. Moreover, the microbiologicaltests (23) did not show any significantincrease of the germ counts over thisperiod.In order to achieve a better distinctionbetween test products, in addition tothe Single soil, a ballast soil is added tothe cleaning cycle of the dishwasher.This ballast soil, in form of a frozenlump, largely consists of fatty type in-gredients as well as protein and starchcontaining food and as coloring com-ponents, tomato ketchup and mus-tard. In justified cases the addition ofthe ballast soil can be waived.These chosen soils were evaluated us-ing 2 test series in different participat-

ing test laboratories. During the teststhe description of the test methodswas optimized with the aim of pre-venting mistakes and avoiding devia-tions. The detailed description of thepreparation of the soils and the condi-tions under which the comparativetests were carried out are presented inpart B.

bleachable

persistent/burnt

Tea

Minced meat onglass

Milk in themicrowave

Starch mix

visual/photo catalog



gravimetric

Visual (colorreaction)/photo catalog

gravimetric

new

Altenschöpfer (13)(modified)

prEN 50242 (10)(modified)

dried /starchcontaining

IECSC59A/WG 2(14)

Oatflakes (porridge) prEN 50242 (10)

Egg yolk

Minced meat onporcelain

Egg/milk

Novo (7,8)(modified)

prEN'50242 (10)(modified)

Novo (7,8)(modified)

dried / proteincontaining Visual (colorreaction)/

photo catalog

j gravimetrict

Table 5 Suitable Single soils meeting the required criteria

Cleaner typePhosphateBleach System% Amylase% ProteaseAlcalinity

!compact

*)-

AO1.0

) 6.010.5-11

*) AO = active oxygen 1 ACI =

compact I-

AO2.04.0 i10.5-11 |

activ chlor

R 3

compact |

AO '3.02.0 ;10.5-11 j

compact+

AO1.02.010.5-11

IEC A

klassica+

ACL

12-12.5

Table 6 Description of the experience gained

SÖFW-Journal, 125. Jahrgang 11/99 55

5.2 Persistent / burnt stainsUsing the methods »milk in the micro-wave« and »minced meat in glass ves-sels«, detergent formulations with dif-ferent alkalinity could be clearly dif-ferentiated.While the results from »milk in the mi-crowave« did not recognize the effectof protease activity, in the »mincedmeat in glass vessels« test the effect ofincreasing amounts of protease couldbe recognized. In practice, these meth-ods offer the advantage of a signifi-cantly reduced hazard potential thanbefore, where soils were burnt on oilbaths

5.3 dried /protein containing soilsThe method »minced meat on porce-lain plates« delivered results that leadto the conclusion that both high alka-linity and increasing amounts of pro-tease result in an increase in cleaningefficiency up to a plateau level. It wasfound to be advisable to spray the res-idues of meat protein with a solutionof Ninhydrin in order to make themmore visible. Altogether, this meat soildried at 120 °C is harder to removethan the meat soil of EN 50242 (DIN44990) dried at 80 °C.The detergent formulations in the testcould be differentiated significantlybetter with the methods »egg yolk«and »egg/milk« applied on steel plates.Here, the effects of protease could berecognized clearly, while the effect ofalkalinity was relatively minor. In thefirst test series it was found that withthe egg yolk soil even a protease freetest detergent with high alkalinity - incomparison to the water value - a notinsignificant cleaning result wasachieved, albeit with widely fluctuat-ing values. The reason for that wasfound to be due to too thick layers ofegg yolk, which - due to the high al-kalinity of the IEC reference detergentA - partly tended to flake off. Due tothis f act, the WG decided to reduce thethickness of the applied egg yolk byhalf. The success was observed in the2nd test series, where the effect of theprotease could be recognized clearlyfrom the results, while a high alkalin-ity had a smaller influence. Soil remov-al using the IEC reference detergent Awas found to be of the same order ofmagnitude as the water value. Theclear protease effect could also be ob-served in the results of the egg/milksoil, where the alkalinity seemstohaveno influence on the cleaning perfor-mance. The results of the egg/milk testalso showed clearly the protease ef-fect, whereas the alkalinity did not ap-pear to effect the cleaning Perfor-mance.

5.4 dried / starch containing stainsOriginally it was assumed that thestarch containing soils were exclusive-ly specific to amylase. Using the »por-ridge« (oatflakes) method, which wasadopted from the suggested methodEN 50242 (DIN 44990), this does not al-ways follow. The results of the test se-ries showed that both the effect of theamylase and the effect of the alkalin-ity were perceptible. However, deter-gent formulations with minor amylaseconcentrations can clearly outperformthe high alkaline detergent type A interms of cleaning efficiency.The working group also dealt for ashort time with a gravimetric evalua-tion. Therefore, it should be men-tioned, that even a detergent with amedium cleaning efficiency on starch,as e. g. IEC reference detergent type A,removes about 90 % of the starch. Thishigh specific iodine/starch reaction canstain food residues so intensively, thatthe remaining 10 % can be clearlyidentified. Marks of 8-9 denote acleaning efficiency well above 95 %(determined gravimetrically).The method »starch mix« is indeedmore time consuming, but offers a lin-ear differentiating gravimetric evalua-

tion. The test results clearly show theinfluence of the increasing amylasecontent and that the alkalinity onlyprovides a minor contribution to thecleaning Performance.

6. Evaluation

The working group's initial philosophywas to determine a selection of suit-able Single soils from the 4 differentsoil classes: bleachable, persistent/burnt, dried/starch containing, anddried/protein containing. Over thecourse of the test series it became ap-parent that the cleaning Performanceon Single soils can often not be charac-terized by just one Single parameter.The influence of specific parameters ispresented in Table 7.For a simple presentation of the re-sults, especially as evidence of causeand effect relationships in terms of thenature and amount of different ingre-dients, the results of the Single soils

Soil

Bleach systerrAlkalinityProteaseAmylaseOtherinfluence

tea

) +

_,phos-phate

• "

milk mincedmeat on

glass

+ ; +' +

!

minced meatporcelain

++

eggyolk

(+)+

e99 [egg/milk porridge starch

(+)

Table 7 Influence of the detergent composition on the cleaning efficiency of theSingle soils

The result.3 of 8 indspenOer i t t&sts we ie cjroupedas -vhov/ri be low in io 4 " f inget p r i n l " c lasses

. - . • : : •= g i v . ' i i • •_- . - t : i ; j | ::;• g » . V i f j - .v i - . ' i in T r j r o i i n

bleachable amylases pecific

><

ü—

50 %

taCB

"U

orrl

n.

50 %

persistent/burnt

•S 1

ilk in

1ic

row

:

E E

5 0 %

'S

i•§Js

et

.nV

19U>

o

5 0 %

p r o l e ;i -a eS pl'CltlC

o e>

1 1

ict:

J rr

cel.

im

I I3 3 7,

-yol

k

Olöl

3 3 EÄ

E

&BiSW

li:.J

1 00 V.

Fig. 1 Presentation of the general result

56 SÖFW-Journal, 125. Jahrgang 11/99

can be combined into the 4 mentionedcategories. For calculation, the clean-ing results ofthesinglesoilsareinclud-ed proportionately as presented inprincipal in Fig. 1.From this, a so called »fingerprint« ofthe specific detergent is being ob-tained, which illustrates the strengthsand weaknesses in relation to the 4 sollclasses.As an example from the practice, theresults of the 2nd test series are beingpresented in Fig. 2.The different composition of the testdetergents e.g. according to thebleach system as well as the content ofprotease and amylase can be recog-nized in the cleaning results. How theSingle soil described so far fulfil thementioned criteria of Table 4 is pre-sented in Table 8.

P 2IEC A

water valuebleachable amylasc-

specjficpersistent protease-

specific

Fig. 2 Results of the 2nd test series

Tea

Minced meat on iglass dishes !

Milk in the +microwave j

Starch mix

Porridge +

Eggyolk

Minced meat on ! +porcelain plates

Egg/milk

+ = good - = bad

+

+/-

+

-

+

+

+/-

[

++

+

+VV

+

+

+

+

+

+

+

+

+

*) Fluctuating results with the dassical detergent IEC A owing to its high alkalinity

+•

+

++

+

+

7. Summary

In the opinion of the working groupthe new method is suitable to morecomprehensively determine the per-formance profile of machine dish-washer detergents than previouslyknown methods. This is, however, be-ing achieved by a greater effort in thepreparation of soils. On the otherhand, the soils discussed here have theadvantagethattheirstoragelifeclear-ly surpasses that of all test soils knownbefore. As a result mass production ofthe required quantity of soils is pos-sible in advance, which leads to a sig-nificant reduction in preparation time.Using hitherto gained experience it isintended to further optimize and up-date the methods and where appro-priate develop other soils. At a laterreview, further accumulated experi-ences can be incorporated into the testmethods.

Literature

Table 8 Compliance of the demands on the Single soils

•ft Benckiser Produktions GmbH

•ft Chemolux s.a.r.l.

-fr fit Chemische Produkte GmbH

•& Henkel KGaA

-& Luhns GmbH

-ft Procter & Gamble

•ü Seifenfabrik Budich

•& Lever

-& Werner & Mertz GmbH

-& Institut Fresenius Gruppe

-& Landesgewerbeanstalt Bayern

^Miele&Cie. GmbH & Co.

•ü Stiftung Warentest

•£c TNO Cleaning Techniques

•ft wfk Forschungsinstitut

(1) DIN 44990, Teil 1, »Elektrische Geschirrspülma-schinen für den Hausgebrauch«, Deutsches In-stitut für Normung e.V., Berlin 1989.

(2) IEC 436, »Methods for measuring the Perfor-mance of electricdish-washers«, Bureau Centralde ia Commission Elertrotechnique Internation-ale, Geneve 1981, and amendement 3, Geneve1994.

(3) B. Ohler, D. Auenwald, C. Maluche, C. Walz,»Methoden zur Bestimmung von Teerückstän-den in Porzellantassen«, SÖFW-Journal 121Jg., 6/95, S.439 ff.

(4) M. Spiro, D. Jaganyi, »What causes scum on tea?«, Nature364, 581 (1993).

(5) R. Lemke, »Die Haut auf dem Tee (2) oder: Teemit Zitrone«, CLB 45, 193 (1994).

Table 9 Companies and test institutes which were involved in the developmentof the test methods within the framework of the IKW working group

58 SÖFW-Journal, 125. Jahrgang 11/99

(6) DRV, »Die Haut auf dem Tee«, CLB 44 592(1993).

(7) L. H. Dalgaard, K. Kochavi, M. Thellersen, »Dis-hwashing-a new area for enzymes«, InformAOCS2(1991), Nr. 6, S. 532 ff.

(8) G. Jemen, M. Thellersen, »Enzyme für Maschi-nengeschirrspülmittel«, SÖFW 119 (1993), Nr. 1,S. 37 ff.

(9) D.H. Cater, M.J. Flynn, P.F. Plank, »Use of enzy-mes in dishwashing detergents«, Inform AOCS5(1994), Nr. 10,5. 1095 ff.

(10) EN 50242 »Electric dishwashers for householduse - Methods for measuring the performan-ce«, CENELEC, European Committee for Elec-trotechnical standardization, Brüssels, to becompleted.

(11) UTE 73-176, »Machines ä laver la vaiselle«,Editees par l'Union technique de l'Electricite(Paris 1968).

(12) ANSI/AHAM DW-1-1982, »An American Natio-nal Standard: Household Electric Dishwashers«ASSOCIATION OF HOME APPUANCE MANU-FACTURERS, North Wacker Drive, Chicaqo Illi-nois 60606.

Mediainformation

2000„^sm

(13) T. Altenschöpfer, »Prüfung von Reinigern undKlarspülernfürdas maschinelle Geschirrspülen1. bzw. 2.«, SÖFW 98 (1972), S. 763 ff. undS. 801 ff.

(14) IEC SC 59A/WG 2, (method B1, starch mixture),»Report of the convenor, Mr. Horowitz, to SC59 A«, (October 1994).

(15) V. Lang, M. Linderer, G. Wildbrett, I. Stifter, »Be-wertung der Reinigungsleistung beim Geschirr-spülen«, SÖFW 117 (1991), Nr. 3, S. 104 ff.

M. Rietz, K. Rubqw, M. Teusch, »Bewertung derReinigungsleistung beim Geschirrspülen«SOFW 119 (1993), Nr. 6, S. 340 ff.

(17) M. Linderer, G. Wildbrett, »Untersuchungenzum maschinellen Geschirrspülen - Erarbeitungeines Prüfverfahrens«, SÖFW 119 (1993), Nr. 13,S. 822 ff.

(18) M. Linderer, G. Wildbrett, »Untersuchungenzum maschinellen Geschirrspülen - 2. Mittei-lung: Einfluss der Verfahrensparameter auf dieStärkeentfernung«, SÖFW 120 (1994), Nr. 7, S,405 ff.

(19) M. Linderer, G. Wildbrett, G. Enderle, »Unter-suchungen zum maschinellen Geschirrspülen -3. Mitteilung: Stärkeablösung mit verschiede-nen Reinigertypen«, SÖFW 121 (1995), Nr. 3, S.160 ff.

(20) P. Weinberger, G. Wildbrett, »2. Mitteilung:Entfernen von Stärkerückständen von Glas-oberflächen«, Fette, Seifen, Anstrichmittel 80Jg./No. 2(1978), S. 80 ff.

(21) T. Altenschöpfer, »Enzyme in Spülmitteln fürHaushalt-Geschirrspülmaschinen? I«, Fette Sei-fen, Anstrichmittel, 73. Jg./No. 7 (1971), S. 459ff.

(22) T. Altenschöpfer, »Enzyme in Spülmitteln fürHaushalt-Geschirrspülmaschinen? II«, FetteSeifen, Anstrichmittel, 73. Jg./No. 9 (1971), S.561 ff.

(23) Institut Fresenius »Bericht zur mikrobiologi-schen Stabilität der Testanschmutzungen«,

(16)

Mediainformai-k.'i.

now available

uVerlag für chemische Industrie

H. Ziolkowsky GmbHPostfach 10 25 6586015 Augsburg

Fax: (0821) 325 83-23e-mail: [email protected]

*Correspondence adress:Dr. W. Buchmeierc/o Henkel KGaAWER/Maschinelle SpülmittelD-40191 Düsseldorf

A

SÖFW-Journal, 125. Jahrgang 11/99 59

SÖFW-Journal | 132 | 8-2006 35

DETERGENTSDISHWASHER DETERGENTS

IKW working group automatic dishwashing detergents*

Methods for Ascertaining the Cleaning Performanceof Dishwasher Detergents(Part B, updated 2005)

Keywords: Test methods, dishwasher detergents,German Industrial Association of the Manufacturers of Toiletries and Detergents (IKW)

Introduction

»stubborn/burnt-on« category, at leastone other enzyme-specific type of soilshould be included when selectingthese types of soil.If only four types of soil are tested theseshould be tea, starch mix, egg yolk andmilk in the microwave.To produce the individual soil types,synthetic water should be used ratherthan tap water, with the hardness raisedto 3.00 mmol (Ca+Mg) = 16.8 °d in accor-dance with DIN/EN 60734, method B -salt mixing technique (see Appendix 4).

1. Preface

1.1 Selection of soil typesFor the test, at least one of each of thefour soil types is to be used (bleachable,stubborn/burnt-on, dried-on/amylase-specific and dried-on/protease-specif-ic). Since, due to the influence of thealkalinity of dishwashing detergents,the minced meat on porcelain platesand porridge do not constitute purelyenzyme-specific types of soil but canalso be included to some extent in the

In 1995, under the auspices ofthe German Industrial Associa-tion of the Manufacturers of Toi-

letries and Detergents (IKW), aworking group of mechanical dish-washing experts was set up, whichwas joined by representatives ofleading European test institutesand dishwasher manufacturers. Thegoal of this working group was tochoose appropriate methods ofsimulating routine soiling in orderto determine the cleaning perfor-mance of automatic dishwashingdetergents. Part A of the publica-tion presents the approach adoptedby the working group and how the

group found the methodology. Thispart, Part B, describes in detail theprocedures used to test the perfor-mance of an automatic dishwash-ing detergent.The method was updated in 2005by the working group. Viable alter-natives are given for appliances,dishes or chemicals which are nolonger available. Phloxin B is rec-ommended for colouring the pro-teins instead of ninhydrin. As re-gards the starch mix method anincreased quantity is advised inorder to allow better differentia-tion in the upper performancerange.

■ Contents

1. Preface

Bleachable stains:2. Tea

Stubborn, burnt-on soil:3. Minced meat on glass dishes

4. Milk in the microwave

Amylase-specific soil: 5. Starch mix

6. Porridge(in accordance with EN 50242)

Protease-specific soil:

7. Egg yolk

8. Minced meat on porcelain plates(by analogy with EN 50242)

9. Egg/milk

Appendix 1:Loading plan taking the exampleof the Miele reference dishwasher

Appendix 2:Appliances and raw materials

Appendix 3:Production instructionsfor ballast soil

Appendix 4:Production instructionsfor hard water

Appendix 5:Calibration instructions for the microwave oven

Appendix 6: Photo catalogue

36 SÖFW-Journal | 132 | 8-2006


1.2 Thorough washing of thecrockery/utensilsBefore the individual soil types can beapplied, the various dishes must be thor-oughly washed. This is essential asresidues of certain persistent stains maystill be present on the dishes from previ-ous tests. New dishes should also be sub-jected to three thorough washes beforebeing used for the first time in a test. Thedishes are washed in a laboratory dish-washer at 95°C with a special, commer-cial dishwashing detergent of high alka-linity and containing active chlorine (e.g.»Perclin«, Ecolab). Dishes should be reg-ularly inspected for surface changes andrejected if necessary. It is advisable toseparate each plate with a clean papertowel to avoid damage.

1.3 StorageThe soil should be stored in controlledconditions of 20°C/40 - 60% relative hu-midity as weighing errors may occur,particularly with gravimetric soil typesdue to varying levels of water content onthe surface of the crockery.Storage life under the above conditions isat least 14 days.

1.4 Preparation of thedetergent samplesThe samples to be tested should be asrepresentative as possible of the deter-gent formulation under examinationand should ideally be taken from sever-al different batches. It is therefore nec-essary to pass the contents of a testpackage of the detergent in questionthrough a sample divider before takingsamples for the detergent tests.

1.5 Procedure / Test conditionsThe detergents are tested according tothe following criteria:

Program:50° / 55°C program

No. of test runs:At least 3 tests are to be carried out.When conducting a series of tests in thesame machine it is essential to ensurethat the temperature is identical. On ap-

pliances with heat exchangers, for ex-ample, several prewashes should beconducted so that the temperature iscomparable at a start of each wash cy-cle.

Water hardness:8-10 °d (1.4–1.8 mmol/l Ca+Mg) in thewash cycle for standard products andproducts with integrated rinse aid (2in1)- as far as the highest water hardnessstated on multi-purpose products.

Detergent dosage:The detergent dosage is as recommend-ed by the manufacturer. If no dosageguidelines are given, the followingdosages are recommended:

classic detergentse.g. IEC type A 30 g

compact detergents e.g. IEC type B or IEC C 20 g

or 1 tab.

No. of soiled items:six of each kind

Additional ballast soil:50g of ballast soil in the form a frozenlump in the main wash cycle.

The frozen soil consists of foodstuffs (seeAppendix 3), especially food containingstarch, protein and fat, and it also con-tains colourings, e.g. ketchup and mus-tard. This additional soil is intended tosimulate the presence of easily remov-able food residues and provides an addi-tional load for the cleaning solution.

Use of rinse aid:It is left to the test laboratories’ discre-tion whether to use a rinse aid.

Machine load:For the dish loading plan, see Appendix1 which uses the example of the Miele G590 reference machine conforming toEN 50242. If another test machine isused, the loading should comply with theplan as closely as possible.

2. Tea

2.1 Apparatus• Tea cups: The sides of the cups should

be 6-8 mm thick (e.g. Fa. Bauscher,art. no. 6215/18 or Schönwald colour:white form: 98L/ 0.19)

• Pipettes 100 ml, 20 ml or automaticmetering pump

• Strainer, mesh width 0.5 mm• Container for boiling / pouring out

the tea• Eppendorff pipette (0.1 ml)

2.2 Raw materials• Black tea, namely Assam

(e.g. Teekanne or other company )• Synthetic water

(3.00 mmol Ca+Mg as per Appendix 4)• Stock solution of ferric sulphate

2.3 Pre-treatment of cupsSee preface (thorough washing)

2.4 Preparation (for approx. 20 cups)Mix 2 litres of synthetic water with 0.1 mlof ferric sulphate solution and bring it tothe boil. Pour boiling water onto 30 g oftea in an open container and leave to brewfor 5 min. Then pour the tea through astrainer into another temperature-con-trolled vessel.

2.5 Test procedureThe clean cups are filled with 100 ml oftea such that the temperature of the teain the cups is 85°C. The initial tempera-ture of the poured tea is about 93°C. Re-move 20 ml every 5 minutes with apipette until all the cups are empty (5times). This process is then repeated oncemore with freshly brewed tea.

2.6 Evaluation:Visual with reference to the photo-graphic catalogue (Appendix 6).

2.7 Important remarks:- Initial temperature in the cup is 85 °C

(temperature of the tea when pouredis about 93 °C).

SÖFW-Journal | 132 | 8-2006 37


- Thickness of the tea cups determinesthe tea cooling rate

- Assam tea is particularly difficult toremove

- Thorough washing of tea cups:household dishwasher/65 °C/detergentIEC A or laboratorydishwasher/95 °C/commercialdetergent

- When drawing off the tea, make surethat the tip of the suction devicepenetrates the skin of the tea beforestarting to draw off the tea

- Before washing, the soiled cups arestored for at least 3 days in a roomwith constant conditions (20 °C, 60%relative humidity).

- It was evident that the tea cups werenot sufficiently darkly stained whenusing synthetic water the hardness ofwhich had only been supplementedwith Ca and Mg ions. For this reasonit was decided to add ferric ions to thesynthetic water to produce a darkertea stain.

Production of the ferric sulphatestock solution: In a 1-litre beaker dissolve 5g Fe2(SO4)3

(see chemical list) + 1 ml HCl (37%) indemineralised water and fill to 1 litre.Using an Eppendorff pipette, add0.1ml of the solution to 2 litres of tea.

3. Minced meat on glass dishes

3.1 Apparatus:• Drying oven (recirculating air) up to

300°C (e.g. Heraeus)• Crystallising dishes

(e.g. Duran/Schott, diameter 115 mm, height 65 mm)

• Mincer (hole diameter 3 mm)• Rubber spatula• Freezer cabinet• Kitchen hand blender

3.2 Raw materials:• A total of 225 g lean pork and beef

(half and half)• 75 g egg (white and yolk)• 80 ml synthetic water prepared as per

Appendix 4

3.3 Preparation:Put the finely chopped and cooled meat(50% beef/50% pork with visible fat re-moved) through the mincer twice. Avoidtemperatures in excess of 35 °C. Usinga fork, mix 225 g of minced meat with75 g of egg (white and yolk) and freeze(can be stored for 3 months at -18°C).To soil the dishes, bring the mince-eggmixture (300 g) up to room temperature,mix it with 80 ml of synthetic water andthen blend for 2 min. using a kitchenhand blender. Weigh 3 g ± 0.1 g of thismixture and place in each glass dish.Spread the mince evenly on the base witha rubber spatula. The weighed mincedmeat should not be allowed to stand formore than 30 minutes before the nextpart of the procedure

3.4 Baking conditions:Preheat the drying oven to a tempera-ture which yields 200 °C after insertingthe glass dishes (experiment beforehandto determine this temperature). Afterloading, reset the temperature controllerto 200 °C. Bake for 10 min at 200 °C.After removing the crystallising dishes,do not put new samples in until the ini-tial temperature has been reached again

3.5 Evaluation:Visual with reference to the photograph-ic catalogue (Appendix 6).

3.6 Important remarks- If pork is not avilable beef can be

used on its own- Make sure that the temperature in the

drying oven does not drop below200 °C after inserting the glass dishes.

4. Milk in the microwave

4.1 Apparatus:• Mikrowave oven with a glass rotating

plate, at least 750 W output (e.g.Bosch or Miele), without an overloadcut-out, calibrated

• 150 ml small glass beakers (diameter 60 mm, height 80 mm)(Caution: pictures in photographiccatalogue show 250 ml / tall form)

• Serial dispenser (e.g. Fortuna Optifix Basic 10 ml, Graf, Wertheim)

• Thermal cabinet (recirculating air)

4.2 Raw materials:• Semi-skimmed UHT milk

(1.5 % fat, ultra-heat treated,homogenised)

4.3 Preparation:Set the microwave to an output of 450 W(see calibration instructions in Appendix5).To preheat the microwave, arrange sixbeakers containing 50 ml water sym-metrically around the edge of the rotat-ing plate and heat them for 10 min. Thenpour 10 ml of milk at room temperatureinto each of the six glass beakers andarrange them in the same pattern as be-fore on the rotating plate and heat themin the manner described below. Makesure that the exact heating time is ob-served in order to ensure that the resultsare consistent.After heating, the milk soil is post-treat-ed for 2 hours at 80 °C in the thermalcabinet.

4.4 Baking times:The baking time is 10 min at 450 W.Since the actual output of microwaveovens may deviate from the setting, itshould be checked every three months,in accordance with the relevant instruc-tions (conforming to EN 60705, see Ap-pendix 5). Depending on the degree ofdeviation, the baking time should beadapted either with an independent timeswitch or, in the case of microwave ovenswhich can be set to the nearest secondin the 10 minute range, by varying theoven's own time setting.

The exact baking time (in seconds) shouldbe marked on the microwave togetherwith its period of validity.

4.5 Evaluation:Visual with reference to photographiccatalogue (Appendix 6)

38 SÖFW-Journal | 132 | 8-2006


4.6 Important remarks– Microwave without a safety cut-out– Adhere precisely to the specified

heating time down to the nearestsecond

– Regular calibration of the microwave

5. Starch mix

5.1 Apparatus:

• Water bath (e.g. IKA TS 2)• Glass beaker

(depending on the quantity of themixed starch)

• Glass beaker for weighing the starch• Electric laboratory stirrer - blade-type

agitators• Serial dispenser (e.g. Fortuna Optifix,

Graf/Wertheim)• Glass plate, arcoroc®, »Octime« series,

Cristallerie d´Arques, black, octago-nal, Ø 25 cm (from edge to edge), in-ner surface area 270 cm2, individual-ly numbered or arcoroc® Cosmos, flat23 cm, no. 10980

• Rack for storing and pre-drying thesoiled plates horizontally

• Thermal cabinet (recirculating air),e.g. Memmert or Binder

• Balance, weighing range up to 1200 g,weighing accuracy 1 mg

5.2 Raw materials:

The following types of starch are re-quired:

• Potato starch:e.g. no. 85650 Fluka Biochemica

• Maize starch:e.g. no. 85652 Fluka

• Rice starch:e.g. no. 85654 Fluka

• Wheat starch:e.g. no. 11685 Merck or no. 85649 Fluka

• Synthetic water as defined inAppendix 4

5.3 Preparation:Make an adequate quantity of 0.65%starch suspension depending on thenumber of plates to be soiled. The quan-

tity can also be multiplied, e.g. using a1.3% or 2.6% starch suspension. The pro-cedure described uses a 0.65% starchsuspension.

Example for a 1000 g batch:Weigh 993.5 g of cold synthetic water asdefined in Appendix 4 into a 2-litre glassbeaker (deep version). Place the glassbeaker in the water bath (which is stillswitched off) and position the stirrer asclose as possible to the base. Weigh1.625 g of each of the four starch types(total weight 6.5 g) and pour into thesecond glass beaker.Stirring continuously, transfer the starchmixture into the beaker of cold water.Cover the glass beaker containing thestarch mixture (e.g. with aluminium foil)and place in a simmering water bath,stirring continuously, until a tempera-ture of 95°C is reached. Continue stirringat this temperature for a further 10 min.Then remove the glass beaker from thewater bath and, still stirring continuous-ly, allow it to cool to room temperature.Add an appropriate quantity of water tocompensate for any water evaporationloss (reweigh to check).The starch should be stirred continuous-ly but slowly, so that no sediment canform. It should not be stirred too vigor-ously, so that the suspension remainsfree of bubbles and the dispenser doesnot take any air in.

5.4 Starch application/weighing:After thorough washing, leave the platesto stand for at least 24 hours. Weigh theplates accurately to the nearest mg. Thescale should be placed in a cabinet witha door to protect it from air movements.

Now set the dispenser so that about

29.5 ± 0.1 g

of the suspension is metered (this is aguide value; the exact setting must bedetermined experimentally beforehand).

Using the dispenser, measure the exactquantity of suspension onto the platesand distribute it evenly by swilling it overthe inner surface. Now place the plateswith the starch solution horizontally on

shelves and leave them there until theyare visually dry (overnight).Then stack the plates in plate racks andcontinue drying for 4 hours at 80°C inthe thermal cabinet.If the amount is increased ensure thatthe starch film does not peel off.

After drying, leave the plates to cool forat least 1 hour. Then weigh them. Thelayer of starch on the plates shouldweigh between

0.189 und 0.216 g (0.75 ± 0.05 mg/cm2).

Plates deviating from this range cannotbe used. If the plates are outside the ap-proved range, the quantity of starch ap-plied can be adapted by varying thequantity dispensed (in this case 29.5 ml).

After the wash test, place the plates inthe thermal cabinet to dry at 80°C for atleast 1 h.

After cooling, weigh within 30 minutes.

5.5 Evaluation

mg starch released x 100% cleaning performance =

mg starch applied (dry)

5.6 Important remarks- The quantity dispensed must always

be checked before the soiling process.The above mentioned balance shouldbe used to check the quantity dis-pensed. Make sure that the balanceis always horizontal to prevent weigh-ing errors.

- It is advisable to calibrate the balanceonce a day with a suitable calibratingweight (obtained from the balancemanufacturer), particularly if weigh-ing is carried out on different days.

- Use a case to protect the balance fromdraughts.

- If the amount of space available dic-tates that the plates need to bestacked on top of each other, a cleanpaper towel should be laid betweeneach plate.

- Before applying the starch solution,the plates must be free of surface-ac-

SÖFW-Journal | 132 | 8-2006 39


tive soil as otherwise the plate surfacewill not be wetted.

- If no laboratory dishwasher is avail-able for thorough washing, it is pos-sible to use the heavy-duty cycle in ahousehold dishwasher with a classichigh-alkalinity detergent.

- Aluminium foil can be used to preventevaporation losses, particularly dur-ing the boiling process.

- Do not use plates with irregular bases.

- Glass plates can attract a static charge,particularly in conditions of low hu-midity, and this can lead to weighingerrors. This can be prevented by plac-ing the glass dishes on an anti-staticsurface prior to weighing.

6. Porridge(conforming to EN 50242)

6.1 Apparatus:• Soup plates, diameter 23 cm, white,

glazed porcelain (e.g. complying withEN standard, Arzberg tableware or similar)

• Magnetic stirrer with hotplate andmagnetic stirring table

• Stainless steel saucepan• Time switch• Temperature sensor• Thermal cabinet (recirculating air)• Brush for application

6.2 Raw materials:• 50 g porridge oats

(e.g. Peter Kölln, BlütenzarteKöllnflocken)

• 250 ml milk, pasteurised(fat content: 1.5%)

• 750 ml cold water,synthetic, as defined in Appendix 4

6.3 PreparationStir the porridge oats into the water andmilk, heat steadily and boil for 10 min,stirring continuously.Using a brush, spread 3 g of hot porridgeevently on the inner plate surface. Keepthe rim of the plate free.

Quantity applied/area:

10.6 ± 0.5 mg/cm2

Dry the soiled plates for 2 h at 80°C inthe thermal cabinet. When they havecooled to room temperature, the platescan be washed.

6.4 EvaluationAfter washing, the performance is eval-uated by visual inspection of the remainsof the porridge with reference to thephotographic catalogue (Appendix 6).

Immerse the plates in an iodine solution tomake it easier to identify the residual soilfrom the porridge. Prepare the iodine so-lution in compliance with EN 50242.

Important information:If the amount of space available dictatesthat the plates need to be stacked on topof each other, a clean paper towel shouldbe laid between each plate.

7. Egg yolk

7.1 Apparatus:• Stainless steel sheets (brushed on one

side), 10 x 15 cm• Flat brush (pure Chinese hog bristles),

2 1/2”• Glass beaker• If necessary, device for manually sep-

arating egg yolk from egg white Trennen von Eigelb und Eiweiß

• Fork• Kitchen strainer

(approx. 0.5 mm mesh)• If necessary, holding device for im-

mersing and drying (prupose-built)• If necessary, frame for holding device

(purpose-built)• Saucepan (round)• Thermal cabinet (recirculating air)

7.2 Raw materials:200 g egg yolk (approx. 10 - 11 eggs)

7.3 Preparation:The stainless steel sheets to be soiledmust be clean and grease-free. To thisend, thoroughly wash the numberedsheets at 95°C in a laboratory dishwash-

er with a high-alkaline commercial de-tergent (cf. 1.2). Dry the sheets beforesoiling (30 min/80°C/thermal cabinet).The brushed surface of the cleanedsheets which is to be soiled should notbe touched after this point. Weigh the cooled sheets before soiling.Separate the yolks of the raw eggs (us-ing a special device if necessary), stirwith a fork in a glass beaker to ho-mogenise them and pass them througha strainer to remove the coarser particlesand fragments of eggshell.Using a brush, apply 1.0 ± 0.1 g of eggas uniformly as possible over an area of140 cm2 on the brushed side of each ofthe stainless steel sheets, leaving an ap-prox. 1 cm wide unsoiled rim (use adhe-sive tape if necessary). Dry the soiledsheets horizontally at room temperaturefor four hours (max. 24 h). For denaturation, immerse the sheets for30 seconds in boiling, demineralised wa-ter (using a holding device if necessary).Then dry again for 30 min at 80 °C. Afterthis, weigh the cooled egg-coated sheets.After weighing, the sheets must bestored for at least 24 hours at room tem-perature before they can be used.

Approval requirement:500 ± 100 mg/140 cm2

(egg yolk after denaturation).After the wash test, dry again for 30 minat 80 °C in the thermal cabinet andweigh again after cooling.

7.4 Evaluation:

mg egg yolk released x 100% cleaning performance =

mg egg yolk applied(after denaturation)

7.5 Important remarks

- To prevent injury, deburr the steelsheets before they are used for thefirst time.

- No water stains or fluff on the surface(visual inspection/repolish if necessary)

- Leave the freshly coated sheets hori-zontal to prevent the formation ofdroplets on the edges.

40 SÖFW-Journal | 132 | 8-2006


8. Minced meat on procelain plates

8.1 Apparatus:

• Tea plates (Arzberg, white, glazedporcelain) conforming to EN 50242,form 1495, no. 0219, diameter 19 cm

• Fork• Thermal cabinet (recirculating air)• Freezer cabinet• Mincer• Kitchen hand blender

8.2 Raw materials:• A total of 225 g lean pork and beef

(half and half)• 75 g egg (white and yolk)• 80 ml synthetic water as defined in

Appendix 4• Phloxin B, 0.01% in water

8.3 Preparation:(Preparation as for minced meat in glassdishes as defined in section 3).Put the finely chopped and cooled meat(50% beef/50% pork with visible fat re-moved) through the mincer twice. Avoidtemperatures in excess of 35 °C. Using afork, mix 225 g minced meat with 75 gegg (white and yolk) and freeze (can bestored for 3 months at -18 °C).To soil the plates, bring the mince-eggmixture (300 g) up to room temperatureand mix with 80 ml synthetic water.Then homogenise it with a kitchen handblender for 2 min. Using a fork, spread3 g of the minced meat/egg/water mix-ture on each white porcelain plate, leav-ing an unsoiled margin of thumb-widtharound the rim.

Quantity applied/area:11.8 ± 0.5 mg/cm2

Place the plates in the preheated ther-mal cabinet.

Dry for 2 hours at 120 °C.

The soiled plates can be used as soon asthey have cooled. Stack the plates withpaper towels between them.

8.4 Evaluation:After washing, immerse the plates inphloxin B solution (0.01% in water) for

better identification of the minced meatresidues. After washing, the performance is eval-uated by visual inspection of the colourreaction of the minced meat residueswith reference to the photographic cat-alogue (Appendix 6).

8.5 Important remarks

- If pork is not available beef can beused on its own.

- The phloxin B solution should bestored in the dark.

- When working with phloxin B solu-tion gloves should be worn to preventstaining on the hands.

9. Egg/milk

9.1 Apparatus:• Bowl• 50 ml measuring cylinder• Egg whisk• Flat brush• Saucepan (at least 17.5 cm high)• Hotplate• If necessary a holding device for dry-

ing and immersing (purpose-built)• Stainless steel sheets (brushed on one

side), 10 x 15 cm• Laboratory balance (accuracy 1 mg)• Thermal cabinet (recirculating air)

9.2 Raw materials:• 160 g egg (egg yolk and egg white,

approx. 3 - 4 eggs)• 50 ml semi-skimmed UHT milk (1.5%

fat, ultra-heat treated, homogenised)

9.3 Preparation:The stainless steel sheets for soiling mustbe clean and grease-free. To this end,thoroughly wash the numbered sheets ina laboratory dishwasher with a high-al-kaline commercial dishwashing deter-gent (cf. 1.2) and polish dry with a cel-lulose cloth. Thereafter, the soiling sur-face of the cleaned sheets should not betouched. There should be no water stainsor fluff on the surface.Using the egg whisk, beat the raw egg(egg yolk and egg white, 160 g) in a bowl.

Stir 50 ml milk and 160 g egg togetherwithout generating froth. Before soiling,treat the sheets in the thermal cabinet(30 min/80 °C), allow to cool, and thenweigh. Using the brush, uniformly dis-tribute 1.0 ± 0.1 g egg/milk mixture onthe brushed side of the stainless steelsheets (use the balance to check), leav-ing an approx. 1.0 cm wide unsoiled mar-gin along the short sides.Dry the sheets horizontally (for at least4 h and max. 24 h at room temperature).Then immerse the sheets in boiling dem-ineralised water for 30 seconds. Dry thesheets in the thermal cabinet for 30 minat 80 °C. After cooling, weigh theegg/milk sheets. Leave the soiled sheetsfor 24 hours before reuse.

The quantity applied per sheet after de-naturation is:

190 ± 10 mg

Sheets deviating from the specificationsmust not be used.

9.4 Evaluation:After washing, dry the sheets again for30 min at 80°C, allow to cool, and weigh.

mg egg/milk released x 100% cleaning performance =

mg egg/milk applied(after denaturation)

9.5 Important remarks:- No water stains of fluff on the surface

(visual inspection/repolish if neces-sary)

- Keep the freshly coated sheets hori-zontal to prevent the formation ofdroplets on the edges.

upper basket lower basket

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Appendix 1 Loading plan taking the example of the Miele reference dishwasher

Appendix 2a Raw materials for test soils

SÖFW-Journal | 132 | 8-2006 41


eg

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42 SÖFW-Journal | 132 | 8-2006


Device Example Adress Application

Drying oven up Heraeus Heraeus Minced meat in glass vesselsto 300°C W.C. Heraeus GmbH

Produktbereich ElektrowärmePostfach 155363450 Hanau, Germany

Mincer Perforated disk 8/3, Electric appliance stores Minced meat in glass vesselsHole diameter 3 mm Minced meat on porcelain plates

Freezer cabinet Electric appliance stores Minced meat in glass vesselsMinced meat on porcelain plates

Kitchen hand blender Braun Electric appliance stores Minced meat in glass vesselsMinced meat on porcelain plates

Microwave oven with Bosch, Miele Electric appliance stores Milk in microwave ovenglass turntable

Serial dispenser Fortuna Optifix Basic, 1.0 ml Graf/Fortuna Milk in microwave oven,Am Bildacker 3-7 Starch mix97877 Wertheim, Germany

Water bath IKA Temperaturheizbad Janke & Kunkel GmbH & Co.KG Starch mixIKA LabortechnikPostfach 126379217 Staufen, Germany

Electric laboratory stirrer + IKA Eurostar Janke & Kunkel GmbH & Co.KG Starch mix, porridgeblade type agitators + Postfach 1263paddle agitator 79217 Staufen, Germany

Recirculation thermal Memmert or Binder Memmert GmbH & Co. KG Starch mix, porridge,cabinet Postfach 1520 minced meat on porcelain plates,

91126 Schwabach milk in microwave ovenBinder GmbHPostfach 10278502 Tuttlingen, Germany

Balance with range up Sartorius Sartorius AG Starch mix, egg/milk, to 1200 g, Weender Landstr. 94-108 egg yolkaccuracy 1 mg 37070 Göttingen, Germany

Magnetic stirrer IKA RET basic Janke & Kunkel GmbH & Co. KG Porridge, egg/milkwith hotplate Postfach 1263

79217 Staufen, Germany

Appendix 2 b Apparatus

SÖFW-Journal | 132 | 8-2006 43


Soiling Qty. Item Description and Manufacturer

Tea 6 Tea cups e.g. Bauscher; no. 6215/18orSchönwald; colour: white; form: 98L/0.19Rehauerstr. 44-54,95173 Schönwald, Germany

Minced meat, encrusted 6 Crystallisation dishes e.g. Duran/Schott; ∅115 mm; h 65 mmNo. 213114908; Schott GlaswerkeHattenbergstr. 1055014 Mainz, Germany

Milk in the microwave 6 Glass beakers e.g. Witeg;150 ml short version, ∅ 55 mm, h 80 mm

Starch mix 6 Glas plates arcoroc®, »Octime« series, black, octagonal, ∅ 25 cm(from edge to edge), inner surface area 270 cm2;arcoroc®, Cosmos series, 23 cm flat, no 10980ARC InternationalAvenue du General de Gaulle62510 Arques / France

Porridge 6 Soup plates ∅ 23 cm; e.g. ArzbergWhite glazed porcelain or equivalent DIN-compliant dishesArzbergLudwigsmühle95000 Selb, Germany

Egg yolk 6 Stainless steel sheets 10 x 15 cm, brushed on one side;WMF AGDr. Fehse73309 Geislingen / Steige, Germany

Minced meat on 6 Dessert plates Fa. Arzberg (see soup plates)porcelain plates White glazed porcelain

conforming to EN 50242, form 1495, no. 0219; ∅ 19cm

Egg/milk 6 Stainless steel sheets see egg yolk

Appendix 2 c List of necessary items to be soiled

44 SÖFW-Journal | 132 | 8-2006


Raw material % content kg for 25 kg

Fat constituentsVegetable oil (e.g. Aro, Metro) 31.6 7.9Margarine (e.g. Homann, Allgäu Margarine) 6.3 1.575Lard (e.g. Laru, Langensiepen & Ruckebier) 6.3 1.575Deep-frying fat (e.g. Aro, Metro, halbflüssig) 6.3 1.575

Protein constituentsFull egg (e.g. Wiesenhof) 15.8 3.95Cream (e.g. Debic, UHT cream, 32 % fat) 9.4 2.35Whole milk, pasteurised, 3.5 % fat 6.3 1.575

Powdered constituents incl. starchPotato starch (e.g. Superior LXJ 72, Emsland) 2.2 0.55Gravy (e.g. Knorr) 1.7 0.425Wheat flour (e.g. Diamant-Mehl, type 405) 0.6 0.15Quark powder (e.g. Dr. Otto Suwelack, Billerbeck) 0.6 0.15Benzoic acid > 99.9 % (chemicals supplier) 0.3 0.075

Other constituentsTomato ketchup (e.g. Kühne) 6.3 1.575Mustard (e.g. Löwensenf »Extrascharf«) 6.3 1.575

Total amount 100.00 25.00 kg

1. Combine vegetable oil and egg and mix thoroughly (approx. 30 minutes).

2. Add ketchup and mustard, still stirring vigorously.

3. Melt the fats, allow to cool to approx 40 °C, then add to the mixture and blend in well.

4. Stir in cream and milk.

5. Add the powdered solid ingredients and mix everything to a smooth paste.

6. Finally, put 50 g of the soil mix into each plastic beaker. Deep freeze them and keep them in the freezer until required.

Hardening the water

1) Preparation of the stock solutions• Solution 1: 800 mmol/l NaHCO3 (67.2 g/l)• Solution 2: 154.2 mmol/l MgSO4 *7 H2O (38.0 g/l)• Solution 3: 446.1 mmol/l CaCi2 *2H2O (65.6 g/l)

2. Preparation of synthetic water with 3.00 mmol Ca+Mg (16,8°d)Put 50 ml of each of the stock solutions 1, 2 and 3 in a vessel with 7 l ofdemineralised water and fill with additional demineralised water up to 10 l. Before using the synthetic water, its pH value should be adjusted to 7.5 with HCl or NaOH.

Ferric sulphate stock solution (only applicable to tea)In a 1-litre graduated measuring flask, dissolve 5 g Fe2(SO4)3 + 1 ml HCI (37%) in demineralised water and fill with demineralised water up to 1 l.

Instructions for checking the actualmicrowave output

The microwave output is calculated inaccordance with EN 60705.

Fill a cylindrical vessel made of borosili-cate (glass beaker, external diameter100 mm, max. glass thickness 3 mm)with 1000 g ± 5 g drinking water.The water's initial temperature shouldbe 10 °C ± 0.1°C. Measure it immedi-ately before placing it in the micro-wave (using a calibrated thermometer).Place the glass beaker in the centre ofthe rotating plate and set the mi-crowave to maximum output.

Now conduct several tests (using a cali-brated stop watch) to determine thetime it takes for water at a tempera-ture of 10 °C ± 0.1°C to be heated by10 °C ± 0.1°C. After each test, the mi-crowave should be allowed to cool forat least half an hour. The test is to berepeated at least once.Measure the water's final temperatureafter mixing it thoroughly.

The following equation is used to cal-culate the microwave's effective out-put:

4187 * (T2 - T1)Peff =

(t - 1.6 sec)

Peff = Microwave’s effective outputin W

T 2 = Final temperature in °CT 1 = Initial temperature (10°C)t = Time switched on in seconds4187 = Water’s specific heat capacity

in J kg-1 K-1

1.6 seconds should be deducted fromthe time switched on as the magnetronin the microwave takes this amount oftime to preheat.

The correction factor is calculated fromthe ratio

nominal output / calculated effectiveoutput (Pset/Peff).

Extend or shorten the baking times bythis factor. A time switch is recom-mended for this.

Appendix 3 Production instructions for ballast soilAppendix 5 Calibration instructions for microwave oven

Appendix 4 Instructions for the production of synthetic water

SÖFW-Journal | 132 | 8-2006 45


Bleachable stains: Tea

unwashed

score 6 score 7

score 1 score 2

score 3 score 4 score 5

score 10score 9

score 8

Appendix 6 Photo catalogue for visual evaluation

46 SÖFW-Journal | 132 | 8-2006


score 3

score 7score 6score 4 score 5

score 9score 8 score 10

Persistent, burnt soil: milk in the microwave

unwashed score 1 score 2

SÖFW-Journal | 132 | 8-2006 47


DETERGENTS

unwashed score 1 score 2

score 3

score 7score 6

score 5score 4

score 8

score 9 score 10

Amylase-specific soil: Porridge (in accordance with EN 50242)

48 SÖFW-Journal | 132 | 8-2006


un-washed

score 1 score 2



score 9 score 10

Protease-specific soil: Minced meat on porcelain plates (by analogy with EN 50242)

SÖFW-Journal | 132 | 8-2006 49


Blind score 1 score 2

score 5score 4

score 8

score 9 score 10

score 6

score 3

score 7

Persistent, burnt soil: Minced meat on glass dishes

* Corresponcence address:Industrieverband Körperpflege- und

Waschmittel e.V. (IKW)Karlstraße 21

60329 Frankfurt am MainGermany

Email: [email protected]

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