to cleaning systems.Transpondersystems,bar codereaders, etc. are under
discussionbut cannotguarantee totalsafety.
The proper dilutionrate and maintenance of a certain concentrationin the
cleaningsystemcan often be monitoredby using onlineconductivitymeters. In
addition,there are a few directonlinemethodsto measure certainingredients in
use solutions.
Manual or semi-automatic controlof use solutions
This is a task that is usuallynot easyto achieve withautomatedequipment.The
concentrationof products witha suitableconductivitycan be controlledby using
conductivitymeters. For a veryfew chemicals thereis a dedicatedautomatic
measuringmethod,e.g. availablechlorine or peroxyacticacid.However, in most
cases the use of summary titrationof the mainingredients or directtitrationor
analysis of the maincomponentsby titration,photometricdeterminationor even
using tracers is required.
29.3.3 Controlduringmanualhandling and refilling
Industrial cleaners and disinfectants are not dangerouswhenhandled properly,
but one should not forget that any manual handling of cleaningchemicals bears
several potentialrisks. Thereare directrisksregarding the personhandlingthe
chemicals.Industrial cleaners havethe purposeof attackingand dissolving fat
and proteins± and theseare maincomponents of humanbodytissue! In addition
thereare risksof fillingcleanersinto containers with wrong or missing labelling.
The problems that couldarisefromthesemistakescan rangefrominsufficient
cleaningvia equipmentdamage and foodcontamination to full-size chemical
accidents.Foodcontaminationmayoccurwhen fillingchemicalsinto foodor
foodadditive containers or whenfillingtainting materialssuchas fuelinto
detergentcontainers.
A goodexample is the caseof a dairyworker whofilledan empty 1000 L
transi-tankwithnitricacidfroma bulktank. He brought the transi-tanksafely
witha forklift truckto the placewhere it was neededand left, because his shift
was finished. About 15 minutes laterthe top lid of the transi-tankwas blownoff
and a darkbrownsmokecolumnerupted20 m into the air as if a miniature
volcano. In verylittletime, the environment was contaminatedwithhighly toxic
nitrousgasestravelling withthe windtowards a nearby shoppingcentre.Only
the immediate actionof jointsecurity forcesincludingseveral fire brigade
teams, paramedics,helicopters and policeforcespreventeda disaster. Whathad
happened? The workerhad selectedan emptycontainerthat had the proper
labellingfor an acid cleaner. Whathe did not knowis that this cleanercontained
organic material that mustnot be blendedwithconcentratednitric acid. The
residues of about 1000 mL in the emptytankhad beensufficient to starta time-
retarded but acceleratingreactionleadingto a completedecompositionof the
nitric acidinto nitrousgasesand steam. Because of this experience,the dairy
managementstopped any refillingof chemicals into othercontainers.
680 Handbookof hygiene controlin the foodindustry