a method for the assessment of in-line stema sterilizability of food processing equipment.pdf

8/11/2019 A METHOD FOR THE ASSESSMENT OF IN-LINE STEMA STERILIZABILITY OF FOOD PROCESSING EQUIPMENT.pdf

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A method for the

I2

assessmentof in-line steam

sterilizability of food-

processing equipment

Ncthcrland*J is wed a$ the lc\ l orgnw m. and h;l\

btcn chosen tor its rela1ively high D-value (umc

IO reduction of 1ht count of colony-forming unn\

by il factor of 10) ot 09 minuh al IXYC (Ret. 7). I I

Iwh d long rtcor: 0: us in o*\prsing the wri l irarwn of

food.

hxf-procewnR equipm ent may need lo be s lcnli red brfore

use. ad I I IS tmpoda nl IO enwe t lut the +ter ihzatwn method

app hed II effectwe. Thus, 1115 necrrwr) IO &ten nm e under

whlrh condi l lon% equipmen t ran h e ~~enhzed Here the pro.

c&m IO 1-1 the m.hn e steam sterlhzabdltv ol c~u~pnwn~

recommem led bv the Trc~ Mrthodr ruhp,roul, of l tw European

Hygienic Equipm ent Dwgn Gmup IEt iEfXt JR summar&

Thic paper 1s

h e

tdth m a sener ot art~rlc~ fea~ urmp lhe

EHEC C IO he publ ished I Trends m food Scwncc A

Techmbgy. The EHE DC is an indepwde nt tonrortwm

formed IO dewlop ku~del~nt~ and

MI

methods tar lhe safe

and hygwmc procnrmg of food. The group include s repre-

sentawes from research im tituter. the locd mdustrv. equ ip

meri t manufacturers and government orR anlzat lon\ in

Europe.

The Tes l Melhodr wbgroup of the Europcun Hygienic

Equip men Dc\ ign Group (EHEDGJ i \ rcpon\ihlc for

producing s tandudixd ICFI maho d\ for awning the

hygienic and awpric capab il i ty of knwl-prwc*\ ing

eqwpnwn ~. Teat method< t iw a\ \e\ \mg I I I-plw c ls iln.

abil i ty and in-hne pswrir~hihty ha\c hccn upproved

hy 1hc EHEDG and publ is twd. P method for aws\ ing

baweris l igh tnes* i\ currently in dm ti Ion (Timprley.

A.W. CI ul . . unpuhl i%hedJ.

This paper dctuil \ the ncommcn dcd

toi

pnwdurr

for asvssing the witah il i ty nt an ircm ~11 ood-prow*+

ing equipm ent for in- l ine s team wri lwl ion. I1 I \ udw-

able IO zondnct in-plucc clcanabdity trials prior IO rhi\

tesl in order IO veri ly the cqwpm cnt\ hyfwmc dc-

sign. The m & ad i * bawd on a Uni lcver Rrwawh

Lahom awium prowt iun+. dnd is de\ igncd 11, indicxtc

whethe r a n item of cquipmrm can hc t rccd inrcma lly

fmm wrhle micmorgani \ms hy in- l int

wxm

wril i l-

at ion.

Materials

Indicator rmc-rooq+amsmt

The bua in is cult iwrd on Irypricaw soy agar (TSA;

BB L. Becton Dickcnwn Micm biotogy Systems.

Cockeysville. MD . USA ). AtIcr incutution al 37C for

2-5 day\. rhc degrw of sporulat ion i\ choked micm

scopicnlly: if il I\ grcatcr rha n IO% . lbc spore, art lw.

vcwd mm phy\ioloyical \ol inc. This w*p en$ iinn is

wu\hcd twice in phy\ioloe lcal \at inc hy ccnuifugation

JI J(ltJtt~ for IS rmnuw \. ruw\pcnQd m phywh pic~l

wlme. and pawuri /cd 31 X0-LPC for IO minutc$. AAcr

cnolm g at IS-25C. *port su\pcn*ion\ arc \tond dl SC

unti l required. Paw xwired sporr ruspenwn~ may he

kcpl t or i l l Icu*t 1 mon th\ withw t Iwing rrltvanc

characwn\uc~. The zmwn trauon of \pwcr in 1he wh-

pension i \ dctcrmmed hv ruw.pl~rmg wth T SA and

mcuh ating at 372 ror 1 day\.

Trypticaw soy broth 11%)

Trypricw wy bmth tTSB; t5g ll trypticaw soy:

BB L. ECLW II Dickenson Microbiolog y Systems.

Cockry\\ i l lc. MD . US A) i\ pum ped 1hroug h lhc lest

appw alw IO pm\& a growth mcdiur.: for any md~cntor

miuroorpanium~ surviv ing on rhe equip.wnt af ter the

~lcri l i l i l lw n 1c~I pmccxturr.

S team

The \&am *h ould bc i rw t rom any conluminanrx that

may advcrwzly affect ~hc gcrminarion and \ubwqu enr

growrh of R \crhri/r\.

Test tquipmcnt

Prior In Icwng. the cqu~pmrnt lo hc invc\cqzaled i*

di \mamlcd ,md t twwghly dcfwubsd twinp i l wlvcnr

such .I \ ulcuhulJ. clwncd by han d twine a ncu~ral Jew-

pcn~ wlut innJ and. I I newwar). dewalcd (wing a 1%.

w/w. qucuu\ accbc acid sohnion). The di\man tlcd

cquipmcnr t i l 1hc comtww w arc relal ivcly \mall)

should then hc ~tcnhrcd in an ou~chluvc al I2OC for 30

minu lc\ Allcmauvcly. the cquipm tnt muy ht re-

awm hlcd and \tcnlircd in-l ine by stcl lm tI?OC t ier

20 minutc\J. Al l corwuction malcrialx inclw iing gab-

kccs. CIC.. mutt hc capahlc ot wh\tan dmg the c eaning

and \tcrihzalion prcredwc


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Fig. 1

Test ptncdtre

Equlpnrnt soiling

W sport w~pen~on I* Jdut~xJ wth phyu&)pic;ll

\illmc to a conccntraion of -5 x IO sporc\/ml. Thi\ di-

luted sport wspcnsion i\ uwd to wt the mncr wfxc~

of the dismantled equipment. includmp all wfaccs

that we in contxt wth each odor aticr reaswmhly

(e.g. p.lrketb an d gasket groow* . The equipm ent I\

ullow ed to dry ut 20-25C (rclwrc humidity SbS ? I lor

22 hour\. nCtcr which it i\ wwwm hlal If the trmpcr.

turc I\ lower undlw )hc hwwdlty I\ highrr than \pcci-

iuJ, Ihc timr ~~llwacd tiw drying muy huvs to hc ex-

tended. A wwul uwwwnt should h made 01 the

could surfuurc~. to ~nwrr ~uWicwn1 drying. prior to

reowmbly A wmplc ol the sporv w+vtwn I* taken

and the cooccntntion dctcrmincd hy pour-Wing wth

TSA and incub ating OI 37C Ior 3 day*.

Slcrihration procedure

An cwmple of u WI cinwt (br ~unductm~ in-hoc

steam stcrihahility testing I\ 4~oun in Fug. I. An ;wp-

trc vcsel. titled wth two awpt~ Ilow-rhnwgh s&c\

(Fig. 2) and cmwinmg an appropriate volume of TSB.

ih wxilizcd in an autwlave at I2OC for 30 mmutc\.

Both Gdc conoection~ of the flow-through valw* arc

short-urcuitcd during autoclavinp (Fig. 2t and the

valve\ are MI in the open positton. Artcr autwlu\m p.

the valw\ ;LF~closed and the wwl i\ inwrporotcd mto

the IC\I crrcuit hy mcam ol the udc conncrtion~ ol the

vnlvc~. Once the WI circmt ha bwn awmblcd. the

itcm 01 cquipmmt to be cvaluatcd I\ mated wth w~m

at 12tYC for 30 minute \. Ihc ctcnm must bc saturated:

the required back pvxorc of 0.2 MPa t2 hart ahwlute

is controlled by mea < f the throttle vahc. Both tem-

puature vod prcswre withm the \ywm mu\t bc m

ngrecment wi th thwe caperted for wturatcd warn: if

tht\ I\ not the ~3% the IN I* vmd tthe htcdrn ma) con-

tain gwx wrh 8, air) To enwre that no cold spot\

m (ormcd m the \ystem. CJR must be taken to enwre

that 1x1 condcnz~~v can accumulate during the steam

twatmcnt. Hhen the wxiliut~on pmcedum is com-

pleted. the two one-way VDIY CS ithcr sudc of the llow-

through \nlw. i\rv clowd l-he How-through valbe\ arc


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Tat\ 4wuld bc conducted a min imu m ol :hrcc Itma.

aaum mg that the thwc naubr urr the h.mle. If wying

rcwI~\ arc 41 &tam ed aflcr il m~wnum ol tivr te\ts i(

Ihomug h examm ation 4wtdd he conducted to asenam

whether the tea have been advcnely inllucncrd b)

Ihults in clthcr the item o f test equipm ent. the tc\( cir-

cuit. or the testing conditions and/or analysis. If any

fault\ are diuzorcred. these should be rcrtiticd and thr

lest\ rqxatcd. IT no ob\imts tauh> arc discovered and

the rcwlts *til l remain variahlc. it can be concluded that

tlw item trl test cputpmcnt is unlikely IO bc witahlc for

m.hne aam ~wihntton unlcw mcwlithxtions to the

cqwpmcnt are mudc or qwxwl tnwuw~ dw lakcn It,

a\wd l ch prohlcm\ in prachw.

lquipmcn t thJl paw\ not tt) bc arili/ohlr hy the

dcrrihed method may he wnli? clhle JI higher tcm-

pcrawrc\ und/w longer wrili/ allon Imw. If wpprtinp

cxpcnmrnl.tl es ldcnrc i\ a\udJh lr. wch cyutpmcnl may

hc clawhed u\ warn wrili/Jhlc m-lint only wth

cxtcndcd ardvatwn lmlc \ awI/w ~c~qeraturc~ htphcr

than I ?tY (. \pccd)mp the apphcahlc tmw\ and tent-

pL%llr~*.

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