aerobic spore-forming microbes belonging to the genera Bacillus and
Paenibacillus(Va»isa»nenet al., 1989,1991;Pirttija»rviet al., 1996;Suihkoet
al., 2004). Thedominance of bacilliin paperand board products maybe
explained by the followingfactors: (1) the recyclingof broke(components
rejectedduring manufacturing thatare reused later in the process), which
contains largenumbersof spore-formers, constantlycontaminating the stock in
the headbox;(2) the thermoresistantspores survivethe heat duringdryingof the
paperand board; (3) mostbacilliare amylolyticwithsome cellulolyticactivity
and therefore growwellin environments rich in starchand cellulose; and (4)
bacilliare veryresistantto manyslime-destroying agentsusedin paperand
boardmachines (Va»isa»nenet al., 1991).
The genusBacilluscomprises a diversecollectionof saprophytic bacteria
widelydistributedin the environment, especially soil and wood.Some,e.g.B.
subtilis,spoilraw materials,whereassome produce slime,whichdisturbsthe
process and causes defects in the end-products. The species B. cereus is
pathogenic, and causestwo typesof foodborne diseases ± diarrhoea and emesis.
Apart from the emetic toxin (cereulide), three different enterotoxins are
produced byB. cereus(Granum, 1997).Thereare strains ofB. cereuswhich
havebeenshown to causefoodpoisoningat a verylow infectious dose(10^3 ±10^4
bacteria/g) (Anderssonet al., 1995).Bacilluscereusgroupcells, at leastB.
Fig. 24.1 Sources,problemsand controlof microbialcontaminantsin the paperand
packagingindustry.Managingcontaminationrisksfromfoodpackagingmaterials 383