Food Safety Magazine, February/March 2013

Food Safety Insider: Sanitation SolutionsRapid Cleaning ValidationTestswww.weberscientific.comAwidely publicized press release in 2010 from the SafeFoods Coalition and the Pew Initiative estimated the costof foodborne illness to be $152 billion annually. Accordingto Ben Chapman of North Carolina State University, other studies,using a different methodology, show a much higher figure of$1.4 trillion. Either way, it is obvious that foodborne illness is anexpensive problem.Of the top five food safetyproblems, “poor plant andequipment sanitation” scored75 percent in another study,clearly correlating good sanitationand food safety.Traditional methods todetermine cleanliness are traditionalvisual inspection andmicrobial assays. Over the lastcouple of decades, adenosinetriphosphate (ATP), proteinresidue and glucose residueswabs have also becomeestablished methods.Richard F. Stier, consulting food scientist and Food SafetyMagazine Editorial Advisory Board member, has indicated thattraditional methods of determining cleanliness, such as visualinspection and microbial assays, have both value and limitations.Microbiological analysis typically requires two or more days tocomplete, and a particular analysis such as aerobic plate count(APC) is limited in the types of microorganisms detected. Further,microbiological analyses do not detect organic residue resultingfrom ineffective cleaning. Visual inspection only allows gross levelsof organic residue—those that are visible to the naked eye—tobe detected.Mr. Stier has also suggested the following for hygienemonitoring:• Ideally, should be in “real time”• Simple, easy-to-use tools• Allow for rapid response• Ease of documentationA number of products manufactured by Hygiena and availablefrom Weber Scientific nicely meet these criteria.The protein residue swabs include ALLER-Snap and PRO-Clean. Both detect protein residues left on a surface aftercleaning, are read through a colorimetric change without aninstrument and have different levels of sensitivity.With ALLER-Snap, you swab a surface, release the reagentand incubate the device for 15 minutes. If protein residue ispresent, the reagent will turn purple. The color change providesa semi-quantitative measure of the surface cleanliness. Themore contamination is present, the quicker and darker the colorchange. This swab detects down to 1 µg protein. This extraordinarysensitivity is suitable for allergen monitoring. The cost pertest is around $2.00.PRO-Clean works similarly but doesnot require an incubation step. A positivewill also turn purple with results inunder 10 minutes and most changestaking place in under 60 seconds. It detectsdown to 10 µg protein and costsaround $1.50 per test.SpotCheck detects minuteamounts of glucose, which is a componentof 85 percent of all foods andbeverages; since it measures simplesugars, you can detect all major foodgroups with or without any proteincontent. Expect to pay $1.30 to $1.70per test.ATP bioluminescence technologymay offer higher sensitivity, in someinstances, to colorimetric swabs.All living organisms contain ATP. Inhygiene monitoring applications, ATPbioluminescence systems are generallycalibrated using a relative lightunit, thresholds for “clean” or “dirty.”Completely clean surfaces—thosefree of food residue and microorganisms—willnot have detectable levels ofATP. Unclean food manufacturing andpreparation equipment and utensils willhave recoverable amounts of ATP fromfood residue and perhaps microbialcells. Keep in mind that ATP measuresboth live and dead organic matter so itmeasures “clean or dirty.” Detection ofmicrobes, if present, is coincidental.The Hygiena ATP system uses aluminometer and their all-in-one swabdevice. Depending upon your particularneeds, two luminometers are available:systemSURE PLUS or EnSURE(which can also measure coliforms usingother swab devices); and a choiceof two ATP swab devices, SuperSnapor Ultrasnap. The procedure is thesame throughout: swab, activate, insertinto the instrument and read the resultsin 15 seconds. And since ATP is instrument-based,it comes with softwarethat walks you through the establishmentof your hygiene protocols.SuperSnap detects to 0.1 femtomoles(the smallest possible detectableamount) of ATP. Ultrasnap detectsto 1.0 femtomoles. The EnSURE andsystemSURE PLUS luminometers havea sensitivity to 0.1 and 1.0 femtomoles,respectively. An aseptic fill operation,for example, may want the higher detectionlevel compared to a distributionarea. Per test, swab costs run around$2.00.40 F o o d S a f e t y M a g a z i n e