The sterilisation of spices, herbs and vegetable ... - Sterigenics

The sterilisation of spices, herbs andvegetable seasonings:Understanding the options

The spice of lifeSpices, herbs, seeds and dehydrated vegetable substances bring a world offlavours, aromas and colours to food.Harvested in the rural reaches of places such as India, China and Indonesia, spicesand herbs develop their flavors and fragrances by fermenting in the sun, drying inthe open air, and through processing techniques such as roasting and grinding.Once the appropriate flavours and aromas have been attained, the flavouringagents are shipped to brokers around the world using methods of transportationranging from open barges to refrigerated trucks.Unfortunately, during their long journey to the table, spices and herbs becomecontaminated with bacteria and molds. Bacterial contamination may come fromsoil, insects, bird or rodent droppings or from the water used in processing. Fungalgrowth may occur before or during drying, or during storage or shipping.In any event, the consequences can be significant.

The riskofcontaminationBacterial contaminationBacteria such as Bacillus cereusand Clostridium perfringens can causea variety of foodborne illnesses.Fortunately, most foodbornepathogens cannot survive modernsanitation measures. Even in caseof extreme contamination, bacteriathat remain after processing areunlikely to tolerate further cookingor heating.Salmonella has occasionally beenfound in spices (such as pepper)and herbal teas. Though normallydestroyed by thorough cooking,the Salmonella in spices can causeillness when the spices are addedto food toward the end of thecooking process, when foods areimproperly refrigerated or whenleftovers are improperly stored forseveral days.The additional threat of pestsPests such as beetles and lessergrain borers are also commonlyfound in spices, seeds, herbs andprepared seasonings. Fortunately,since infectious pests are moresusceptible to decontaminationmeasures than bacteria or molds,technology used to controlmicrobial contamination will alsokill pests.Molds and fungal growthsLeft untreated, mold can produceaflatoxins, which destroy theflavour and colour of the ingredientsand make them unsuitable for use.

Two effectivesolutionsThe world leader in microbialreduction services, Sterigenicsoffers the spice and food processingindustries a choice of twosanitation options: ethyleneoxide (EO) fumigation andirradiation processing.While both effectively killorganisms, the challengespresented by the bulk packagingof spices and herbs have madeethylene oxide fumigationand gamma processing themethodologies of choicedue to their efficient, highdensitypenetration.Often, the final destinationof the spice and herb product playsa dominant role in the technologyselection. Although EO fumigationis widely utilised in the US, itis not currently accepted in theEuropean Union.EO fumigation:the original standardof excellenceA trusted means of spice sterilisationfor more than 60 years, ethyleneoxide fumigation uses alkylationas its mechanism of action.Usage of EO for food sanitationaccelerated dramatically in the1960s with the discovery that EOfumigation could significantlyreduce spoilage organisms in spicesand spice blends. From that pointuntil the approval of gammaradiation in 1988, EO was thetool of choice for herb and spicedecontamination in the US.In 2001, the US Food and DrugAdministration (FDA) approvedEO as a reconditioning technologyfor detained raw spices. Today,EO is also approved for spice blends,but only those that do not includesalt (10CFR §185).In order to ensure an effective result,the EO gas must be able to diffusefreely throughout the product beingtreated, making breathablepackaging a necessity. In addition,because a non-volatile residueremains after processing, an aerationperiod is required to allow theresidue to dissipate. Typically,the aeration process is completewithin 24 hours.Since ethylene oxide processingdoes not require labeling in the US,it remains a favoured sanitationagent for a significant number of thecountry’s food processors.Irradiation: today’smost effective and mostpreferred choiceIrradiation is achieved eitherby gamma rays, pure energy raysemitted from Cobalt-60 andsimilar in many ways to microwaves,or by accelerated electrons,commonly known as electronbeam (E-beam) irradiation.Approved by the FDA in 1988,gamma processing is the preferredmethod of food sterilisation inthe US and on a global basis.Less harsh and intrusive than EO,irradiation uses ionising energyto kill bacteria, mold and insectswhile retaining the flavours,colours, aromas and antioxidantproperties of the flavouringingredients.While it is true that gammaprocessing can affect the sensorycharacteristics of some flavouringagents, the extent of the effectand the dose level required tocause a perceptible change variesby product. Ingredients thathave been stored for a long timeor those whose quality, flavour oraroma are not up to usualstandards may be more affectedthan better quality spices.A penetrating sterilant, gammairradiation leaves no area ofthe product or packaginguntreated. Even high-densityproducts such as 250-liter fiberdrums can be readily processedwithout the need for breathablepackaging. Furthermore,gamma rays create no residues,so aeration is not required.

Likely effects of irradiationprocessing at various dose levelsTest Dose(in kGy)Ingredients TestedResults4-10 Black pepper, white pepper, turmeric, Coliforms eliminatedrosemary, basil5 Coriander, cumin, turmeric, chili, Starting fungal counts of 10 2 -10 6rosemary, basileliminated; coliforms eliminatedGarlic powderWhite pepperNutmegGingerColiforms not detected3.0 log reduction total plate count4.0 log reduction total plate count2.0 reduction total plate count6.5 Paprika, crushed red pepper Standard plate counts

Irradiation in combinationwith other food processingSince spices are used in foods thatundergo other processes, it isimportant to know how irradiationworks in combination with theseother treatments. As a rule,irradiation improves the abilityof subsequent processes to furtherlower microbial contamination.Microbial contamination levelsin irradiated spices continueto decline during storagebecause radiation-damagedmicroorganisms cannotreproduce. This has been foundto be true even when storageoccurs at elevated temperaturesand relative high humidity forseveral months.Microorganisms that surviveirradiation are much moresensitive to heat. As a result,food groups that are heated andheld at constant temperatures(such as soups from mixesused in food service operations)can have a longer storage life.Surviving microflora havebeen found to be less resistantto sodium and more sensitiveto pH changes, moistureand growth temperatures.These sensitivities furtherreduce their ability tosurvive and grow inprocessed food products.A look at labelingFederal labeling requirementsmay be a key factor for some USmanufacturers when makingdecisions regarding irradiationmethodology (21 CFR § 179.26).While labeling is not requiredfor food products containing EOprocessedingredients, productsthat have been decontaminatedusing gamma processing mustprominently display theinternational symbol signifyingirradiation—known as the“Radura”—and a statement thatthe products have been processedwith irradiation. In the EU, everyirradiated product must be labeledas “ionised.”Not surprisingly, labelingrequirements vary from countryto country:In the U.S., wholesale or bulkpackage labels, invoices orbills of lading must includea statement along the lines of“treated with radiation—do notirradiate again” if the productis shipped to a foodmanufacturer or processorfor further processing, labelingor packaging.Irradiated spice and herbproducts that are merelycleaned, chopped, graded and/orrepackaged must retain theirradiation label. However, anirradiated product that is roasted,heat treated or blended withother irradiated or non-irradiatedspices or ingredients does nothave to be labeled as irradiated.Labeling requirements vary fromcountry to country.Worldwide, the Radura symbol is the consumer’s assurance of food safety. Research has confirmedthat, when provided with factual information about food irradiation, consumers will chooseirradiated products with confidence.

Ensuring the highestquality and safetyNo matter which sanitation technologyis selected, in order to preventthe contamination of finished foodproducts it is important for dryingredients to enter the processing areawith very low bacterial and fungalcounts. In most cases, only sterilisedspices can meet the low plate countsspecified by food processorsmanufacturing under HACCP 1 orISO 2 standards.Whenever products present a greaterthan average risk of foodborne illnessor economic loss from spoilage,processors should use spices withthe lowest possible microbialcontamination. Such at risk productsinclude:ready-to-eat foods that areminimally processed and do notrequire further cookingrefrigerated foods sold at the retaillevel and thoserefrigerated foods used in foodservice operationssnack foods, deli meats and cheeses,cooked poultry, meat products, saladdressings and refrigerated saladssold at retail.Sterigenics International,the sterilisation expertThe world’s leading supplier of microbial reductionservices for food products and food packaging,Sterigenics offers more technologies and morelocations than any other provider.With 40 processing centres across North America,Europe and Asia, and the widest range of technologychoices, you can be sure Sterigenics is able toprovide technology for every product and everyprocessing requirement.To learn more about how Sterigenics’ expertiseand technology can help your company extendproduct shelf life and prevent foodborne illness,call 800.472.4508 or visit www.sterigenics.com.1Hazardous Analysis of Critical Control Points(HACCP): Irradiation and HACCP arecomplementary weapons in the battle to ensurethe safety of our food supply. HACCP is a planthat identifies the hazards associated witheach food item and determines how each hazardcan be reduced or eliminated. The microbialcontamination of spices, herbs, and seasoningsis a critical control point in many food-processingoperations.2International Organization for Standardization(ISO): A network of national standards institutesfrom 146 countries.

Related applications Botanicals and health supplementsMany suppliers of botanical ingredients andmanufacturers of natural health products relyon irradiation to ensure the cleanliness of theirproducts—with little or no effect on activeingredients. As reported in 1998, tests of irradiationeffects on active components of 36 traditionalChinese medicines showed less than a 3% lossof active ingredients at doses up to 10.0 kGy.Pet feeds and chewsWhen the feed is destined for domestic pets,resident bacteria could affect the health of thepet’s human family. Additionally, there have beenmultiple cases of children contracting Salmonellosisfrom handling dog chew treats such as pigs’ ears,bullwinkles, rawhide and similar items. Irradiationhas been shown to effectively eliminate thesemicroorganisms.References1. Farkas J. Irradiation of Dry Ingredients. Boca Raton, Florida: CRC Press, 19882. Federal Register. April 18, 1986. 21 CFR § 179. Irradiation in theProduction, Processing, and Handling of Food. Final Rule. pp 13376-13399.3. International Consultative Group on Food Irradiation. Irradiation of spices,herbs, and other vegetable seasonings—A compilation of technical data for itsauthorization and control. International Atomic Energy Agency. February 1992.4. Federal Register. August 4, 1994. 10 CFR § 21, Ch.1. Developmentof Hazard Analysis Critical Control Points For The Food Industry:Proposed Rule; Vol. 59, No 149, pp 39888-39896.5. U.S. Food and Drug Administration, 1995. Irradiation in the Production,Processing and Handling of Food. Code of Federal Regulations, Title 21:pp 388-390.6. Bruhn C.M. 1995 Consumer Attitudes and Market Response toIrradiated Foods. Journal of Food Protection 58: pp 175-181.7. Council of Agricultural Science and Technology, 1995 Food BorneIllnesses: Risks and Consequences. CAST Report No. 122.8. Diehl, J.F. Safety of Irradiated Food, 2nd ed. 1995, M. Dekker, Inc. New York.9. Monk, J.D., Beuchat, L.R., and Doyle, M.P. 1995. IrradiationInactivation of Food-Borne Microorganisms. Journal of Food Protection 58:pp197-208.10. Radomyski, T., Murano, E.A., Olson, D.G. and Murano, P.S. 1994.Elimination of Pathogens of Significance in Food by Low-dose Irradiation:A Review. Journal of Food Protection. 57: pp 73-86.11. Thayer, D.W., Josephson, E.S., Brynjolfsson, A. and Giddings, G.G.1996. Radiation Pasteurization of Food. Council For Agricultural Science andTechnology Issue Paper. No. 7.12. Urbain, W.M. Food Irradiation. 1986. Academic Press, Inc.Orlando Florida.13. Marcotte, M., Tibelius, C., Effect of Irradiation on Microbiology,Chemistry and Active Components of Botanicals, Traditional Medicinesand Herbal Products, 1998.2015 Spring Road Suite 650 Oak Brook, IL 60523 USATel 800.472.4508 Fax 630.928.1701Remylaan 4c box 4 3018 Leuven BelgiumTel +32 (0)16 525220 Fax +32 (0)16 525230www.sterigenics.comSterigenics and the Sterigenics logo are registered trademarks of Sterigenics International.©2007 Sterigenics International RevFS07 Printed in the USA.