International Journal of Food Microbiology 51 (1999) 159–167 www.elsevier.nl / locate / ijfoodmicro Two-dimensional profiles of fumonisin B production by Fusarium 1 moniliforme and Fusarium proliferatum in relation to environmen factors and potential for modelling toxin formation in maize grain a b a a c a , * ´ ´ S. Marın ,N. Magan ,N.Bellı, A.J. Ramos ,R. Canela , V. Sanchis a Food Technology Department , University of Lleida , CeRTA , Rovira Roure 177,25198 Lleida , Spain b Applied Mycology Group , Cranfield Biotechnology Centre , Cranfield University , Cranfield , Bedford MK 43 0 AL, UK c Chemistry Department , University of Lleida , Rovira Roure 177,25198 Lleida , Spain Received 10 January 1999; received in revised form 5 July 1999; accepted 3 August 1999 Abstract This study has examined in detail the effect of temperature (7–378C) and water availability (water activity, a , 0.89 w on fumonisin B (FB ) production by an isolate of Fusarium moniliforme and F . proliferatum on irradiated maize grain after 1 1 incubation for 28 days. The optimum conditions for F . moniliforme and F . proliferatum were 308C at 0.97 a and 158C at w 21 21 0.97 a , respectively. The maximum concentrations were 2861 mg kg and 17,628 mg kg dry wt.maize grain, w 21 respectively. At marginal a / temperature conditions for growth (e.g. 0.89–0.91 a ) no FB was detected ( , 0.1 mg kg ). w w 1 A high variability was found between replicates for F . moniliforme, butnotfor F. proliferatum. These data were used to construct two-dimensional diagrams of all the a 3 temperature conditions favourable for FB production for the first time. w 1 The data were also subjected to a polynomical regression, which demonstrated that there was a very good fit for the range of temperature and at 0.97 a . However, at marginal environmental conditions this was not possible. This sugg w it may be possible to predict within a limited environmental range the potential for significant FB production.  1999 1 Elsevier Science B.V. All rights reserved. Keywords : Fusarium; Fumonisins; Water activity; Temperature; Maize 1. Introduction them, Fusarium moniliforme and Fusarium prolifer- atum are the major producers. Since the elucidation In recentyears, Fusarium species belonging to of fumonisinsby Gelderblom et al. (1988)much Section Liseola have attracted much attention be- work has been carried out on this subject. A number cause of their ability to produce fumonisins. Among of surveyshave shown that a high percentage of samplesof corn-based feed are contaminated by fumonisins (Wilson et al.,1990;Ross etal.,1991). *Corresponding author. Tel.: 134-973-702535; fax: 134-973- They have also been found in samples intended for 702596. E-mailaddress : vsanchis@tecal.udl.es (V. Sanchis) human consumption (Sydenham et al., 1991; Pittet et 0168-1605 / 99 / $ – see front matter  1999 Elsevier Science B.V. All rights reserved. P I I : S 0 1 6 8 - 1 6 0 5 ( 9 9 ) 0 0 1 1 5 - 4