IngentaConnect Transfer of Bacillus cereus Spores from Packaging Paper into Food

Authors: Ekman, Jaakko¹; Tsitko, Irina²; Weber, Assi³; Nielsen-LeRoux, Christina⁴; Lereclus, Didier⁴; Salkinoja-Salonen, Mirja⁵

Source: Journal of Food Protection®, Volume 72, Number 11, November 2009 , pp. 2236-2242(7)

Publisher: International Association for Food Protection

Abstract:

Food packaging papers are not sterile, as the manufacturing is an open process, and the raw materials contain bacteria. We modeled the potential transfer of the Bacillus cereus spores from packaging paper to food by using a green fluorescent protein-expressing construct of Bacillus thuringiensis Bt 407Cry^- [pHT315Ω(papha3-gfp)], abbreviated BT-1. Paper (260 g m^-2) containing BT-1 was manufactured with equipment that allowed fiber formation similar to that of full-scale manufactured paper. BT-1 adhered to pulp during papermaking and survived similar to an authentic B. cereus. Rice and chocolate were exposed to the BT-1-containing paper for 10 or 30 days at 40 or 20°C at relative air humidity of 10 to 60%. The majority of the spores remained immobilized inside the fiber web; only 0.001 to 0.03% transferred to the foods. This amount is low compared with the process hygiene criteria and densities commonly found in food, and it does not endanger food safety. To measure this, we introduced BT-1 spores into the paper in densities of 100 to 1,000 times higher than the amounts of the B. cereus group bacteria found in commercial paper. Of BT-1 spores, 0.03 to 0.1% transferred from the paper to fresh agar surface within 5 min of contact, which is more than to food during 10 to 30 days of exposure. The findings indicate that transfer from paper to dry food is restricted to those microbes that are exposed on the paper surface and readily detectable with a contact agar method.

Document Type: Research article

Affiliations: 1: Department of Applied Chemistry and Microbiology, P.O. Box 56, 00014 University of Helsinki, Helsinki, Finland. jaakko.ekman@helsinki.fi 2: KCL, P.O. Box 70, 02151 Espoo, Finland, VTT, Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Finland 3: KCL, P.O. Box 70, 02151 Espoo, Finland 4: UR1249, Génétique microbienne et environnement, INRA, La Minière, 78285 Guyancourt, France 5: Department of Applied Chemistry and Microbiology, P.O. Box 56, 00014 University of Helsinki, Helsinki, Finland

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