Bacteria in food packaging paper and board - Blogs Unpad

~~~~BACTERIA IN PAPER AND BOARD 131Table 1 Number of bacteria isolated frompaper and board productsNo. of bacteria isolated fromsamples of paper or board frommachines*SpeciesBacillus brevisB. cereus group(B. cereus, B. mycoides,B. thuringiensis)B. glnbispnrusB. licheniformisB. megateriumB. pnlymyxa group(B. pnlymyxa, B. circulans,B. macerans, B. pabuli)B . pumilusB. subtilisNon-bacilliTotalA B C D E3 1 10 82 3 1 9111810 3 31 213 4 23 11 115 2 3 622 30 18 57 9* Quality of the product and pH in the headbox stock of the different paper and boardmachines studied: A, Liquid packaging board coated with kaolin (pH 45); B, fullybleached pigment coated (calcium carbonate and kaolin) liquid packaging board (pH 6-9) ;C, fully bleached liquid packaging board sized with starch with no mineral pigments (pH9-10); D, duplex liquid packaging board of unbleached (80%) kraft pulp topped withbleached pulp (pH 7); E, grease-proof pergamin paper of Ca-sulphite pulp (pH 5-6).Figure 2 shows that the number of spore-forming bacteriain the broke correlated well with that of the finalproduct of the same machine. Of the components that makethe stock for papermaking, the pulp itself was sterile, butthe sizing agents (starch and resin sizers) and mineral pigmentsalways contained large quantities ( 103-106 cfu/g) ofbacteria. Fungi were less frequent (0-102 cfu/g whenAcounted on potato dextrose or Sabouraud maltose agar).Thus the broke was the main, but not the only source ofcontamination of the product. No correlation was foundbetween the numbers of bacteria in the final product andthose in the white water or papermaking chemicals (starch5rI?/ LA A bAAAPA fA /AA AIAMA.AAA-A.~UUA-A-A I I I0 I 2 3 4Log total bacterial caunt/O.l g boardFig. 1 Relationship between spore counts and total aerobicbacterial counts in products or board machine C (Table 1). Eachsymbol represents a sample of one machine rollL I I I II 2 3 4 5Log spore countlg brokeFig. 2 Correlation between the numbers of spore-formingbacteria in board of machine C (Table 1) and the contemporarybroke (rejected board, which is repulped and recycled into theprocess) of the same machine. The symbols represent differentsampling times over a period of two years

132 O.M. VAISANEN ET AL.sizers, resin sizers, kaolin, calcium carbonate, surface sizers)(results not shown).The main contaminant in milk and other dairy productsis B. cereus (Ahmed et al. 1983; Wong et al. 1988), which iscaseolytic (Claus & Berkeley 1986), and may produce toxins(Christiansson et al. 1989). Such properties are undesirablein materials used for milk packaging. We compared strainsof B. cereus group isolated form packaging boards andboard machines with those isolated from spoiled dairy productsand their raw materials using whole cell fatty acidanalysis, phage typing and measurement of minimumgrowth temperature, and found no overlap between thesepopulations (Vaisanen et al. 1990). Thus, although strainsof B. cereus group were commonly found in food packagingpaper and board, their role for dairy product spoilage maybe of little significance.We found hairy spores in one of the B. pumilus strainsisolatcd from food packaging paper (Fig. 3). Cerf & Metro(1977) described similar hairy spores in a strain of B.lichenijormzs isolated from milk. They observed that thesespores were exceptionally resistant to killing by hot hydrogenperoxide, probably due to clump formation through thehairs. 'l'he presence of this kind of spores in food packagingmaterials might thus cause contamination problems in thedairy.Strains of B. polymyxa group were the most frequentbacilli found in boards, but little is known about theirpotential hazards in foods.Fig. 3 Electron micrograph of a thin section of a spore of Bacilluspumilus S96 isolated from paper of machine E (Table 1). The thinsection was double-stained with uranium acetate and lead citrateEight strains were identified as B. globisporus by fattyacid analysis. These strains did not have spherical spores asdoes B. globisporus sensu stricto, but they did grow at+ 4"C, which may be noteworthy considering the use of thepaper or board for cold-storage packaging of food.The dominance of bacilli in the paper and board productsmay be explained by the following facts: (1) the recyclingof broke, which contains large numbers ofspore-formers, constantly infects the stock in the headbox;(2) the thermoresistant spores survive the heat during thedrying of the paper and board; (3) most bacilli are amylolyticand some cellulolytic (Claus & Berkeley 1986; Vaisanenet al. 1991) and thus grow well in an environment richin starch and cellulose; and (4) bacilli are very resistant tomany slime-destroying agents used in paper and boardmachines (Vaisanen et al. 1989), which may give themselective advantage in the environment where these agentsarc constantly used.ACKNOWLEDGEMENTSWe thank S. Piispa for isolation of some of the board bacteria,R. Boeck for fatty acid analyses, E.-L. Nurmiaho-Lassila for electron microscopy, T. Koro for preparation ofthin sections, and E. Elomaa for a part of the data on bacteriain papermaking chemicals and broke. This work wasfinancially supported by Foundation for Biotechnical andIndustrial Fermentation Research and Foundation forResearch of Natural Resources in Finland.REFERENCESAHMED, A.A.-H., MOUSTAFA, M.K. & MARTH, E.H.(1983) Incidence of Bacillus cereus in milk and some milk products.Journal of Food Protection 46, 126128.ANON. (1975) Regulation on milk testing by the Ministry ofAgriculture and Forestry, No. 300175 (in Finnish). Helsinki :Ministry of Agriculture and Forestry.ANON. (1978) Fabrication of single-service containers and closuresfor milk and milk products. Sanitation standards. Washington: U.S. Department of Health, Education, and Welfare,Public Health ServicelFood and Drug Administration. Washington: Government Printing Office.ANON. (1989) Packmittel; Buttereinwickler; Technische 1,ieferbedingungen.DIN 10082 08.89. Deutsches Institut furNormung e.V. Berlin : Beuth Verlag GmbH.CERF, 0. & METRO, F. (1977) Tailing of survival curves ofBacillus lichenrformis spores treated with hydrogen peroxide.Journal of Applied Bacteriology 42, 405-41 5.CHRISTIANSSON, A,, NAIDU, A.S., NILSSON, I.,WADSTROM, T. & PETTERSSON, H.-E. (1989) Toxin productionby Bacillus cereus dairy isolates in milk at low temperatures.Applied and Environmental Mtcrobtology 55,2595-2600.CLAUS, D. & BERKELEY, R.C.W. (1986) Genus BacillusCohn 1872, 174. In Bergey's Manual of Systematic Bacteriology

BACTERIA IN PAPER AND BOARD 133Vol. 2, ed. Sneath, P.H.A., Mair, N.S., Sharpe, M.E. & Holt,J.G. pp. 1105-1 139. Baltimore: Williams & Wilkins.SAI.ONEN, M. (1989) Enzymatic characterization of bacillifrom food packaging paper and board machines. Journal of’NISKASAARI, K., RIMPILAINEN, M.A., NURMIAHO- Industrial Microbiology 4, 41F428.LASSILA, E.-L. & FORSEN, R.I. (1988) Enzymatic lysis ofStreptococcus lactis subspecies cremoris : a method for plasmamembrane preparation of the the slime-forming strain MLS96.Microbios 54, 113-126.VAISANEN, 0. & SALKINOJA-SALONEN, M. (1989) Use ofphage typing and fatty acid analysis for the identification ofbacilli isolated from food packaging paper and board machines.Systematic and Applied Microbiology 12, 103-1 11.VAISANEN, O.M., MWAISUMO, N.J. & SALKINOJA-SALONEN, M.S. (1991) Differentiation of dairy strains of theBacillus cereus group by phage typing, minimum growth temperature,and fatty acid analysis. Journal of Applied Bacteriology10,3155324.WONG, H.C., CHANG, M.-H. & FAN, J.-Y. (1988) Incidenceand characterization of Bacillus cereus isolates contaminatingdairy products. Applied and Environmental MicrobiologyVAISANEN, O., E:Lo, S., MARMO, S. & SALKINOJA- 54,699-702.