Occurrence of molds on laminated paperboard for aseptic packaging, selection of the most hydrogen peroxide- and heat-resistant isolates and determination of their thermal death kinetics in sterile distilled water.
This study aimed at enumerating molds (heat-labile and heat-resistant) on the surface of paperboard material to be filled with tomato pulps through an aseptic system and at determining the most heat- and hydrogen peroxide-resistant strains. A total of 118 samples of laminated paperboard before filling were collected, being 68 before and 50 after the hydrogen peroxide bath. Seven molds, including heat-resistant strains (Penicillium variotii and Talaromyces flavus) with counts ranging between 0.71 and 1.02 CFU/cm(2) were isolated. P. variotii was more resistant to hydrogen peroxide than T. flavus and was inactivated after heating at 85 °C/15 min. When exposed to 35 % hydrogen peroxide at 25 °C, T. flavus (F5E2) and N. fischeri (control) were less resistant than P. variotti (F1A1). P. citrinum (F7E2) was shown to be as resistant as P. variotti. The D values (the time to cause one logarithmic cycle reduction in a microbial population at a determined temperature) for spores of P. variotii (F1A1) and N. fischeri (control) with 4 months of age at 85 and 90 °C were 3.9 and 4.5 min, respectively. Although the contamination of packages was low, the presence of heat- and chemical-resistant molds may be of concern for package sterility and product stability during shelf-life. To our knowledge, this is the first report that focuses on the isolation of molds, including heat-resistant ones, contaminating paperboard packaging material and on estimating their resistance to the chemical and physical processes used for packaging sterilization.
Department of Food Technology, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil. denilet@hotmail.com
Denise Aparecida
DA
Delgado
Anderson
A
de Souza Sant'ana
Pilar Rodriguez
PR
de Massaguer
D005516:Food Microbiology; D005658:Fungi / Q000187:drug effects* / Q000472:pathogenicity*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D019064:Product Packaging; D013242:Sterilization; D013696:Temperature
D006861:Hydrogen Peroxide