Modelling the inhibitory effect of copper sulfate on the growth of Penicillium expansum and Botrytis cinerea

Abstract

Aims: This study aimed to investigate the effect of copper sulfate (from 0 to 8 mmol kg−1) on radial growth rate and lag time of two moulds responsible for vine grapes spoilage: Penicillium expansum strain 25·03 and Botrytis cinerea, strains BC1 and BC2. Methods and results: A new model was developed to describe tailing and shoulders in the inhibition curves. Because of tailing, the minimum inhibitory concentration (MIC), was not defined as the concentration at which no growth was observed, but as the concentration at which the lag time was infinite. The concentrations at which μ = μopt/2, (Cu50), were in the range of 2·2–2·6 mmol kg−1. Radial growth rate of P. expansum and the reciprocal of the lag time were linearly correlated (r = 0·84). In contrast, in the range 0–4 mmol kg−1, an inhibition of growth of B. cinerea was observed whereas germination remained unaffected (i.e. the lag time was constant). In the range 4–8 mmol kg−1, the radial growth rate of B. cinerea was almost constant (c. 1 mm day−1), but germination was inhibited (i.e. the lag time was increased). Conclusions: The MIC values were 4·7 mmol kg−1 for P. expansum, 8·2 and 7·3 mmol kg−1 for B. cinerea strain BC1 and BC2, respectively, demonstrating that some isolates of these moulds are resistant to copper. Significance and Impact of the Study: Copper concentrations at 4 mmol kg−1 would be sufficient to control the development of these isolates, but the toxicity of copper should be extended to other isolates and evaluated in vineyards.

Syntheses and characterization of 2-acetylpyridine-aminoguanidine and its copper(II) complexes: Crystallographic and antimicrobial study

“…That is in accordance with the fact that yeasts, especially C. albicans, are more resistant to high concentrations of copper than other species [46,47]. On the other hand, it is well known that Cu(II) ions inhibit mould growing [48][49][50]. The mechanism of action includes strong Cu 2+ bonding with the amino groups of chitin and chitosane of the mould cell walls, wherein their normal growth is interrupted [51].…”

Study of the antifungal potential of novel cellulose/copper composites as absorbent materials for fruit juices

“…Accordingly, Weaver et al (2010) reported on the sensitivity of several strains of Fusarium, Penicillium and Aspergillus to a copper surface, and found resilient spores of Aspergillus niger. Judet-Correia et al (2011) reported minimal inhibitory concentrations of copper sulphate of about 4.7 mmol kg −1 for P. expansum, and around 8 mmol kg −1 for B. cinerea, demonstrating also that some isolates are resistant to copper. Relevant strain specificities or matrix characteristics have not been fully identified, and consequently provide controversial results.…”

“…Methods C and D released amounts of copper close to the detection limit of the system in water (below 100 ppm). According to Judet-Correia et al (2011), concentrations above 4 mmol kg −1 of copper sulphate are sufficient to inactivate Penicillium expansum and some isolates of Botrytis cinerea, consequently the methods A and B are expected to produce concentrations with antifungal activity. Fig.…”

Predicting and Preventing Mold Spoilage of Food Products

“…To prevent these kinds of food from mold spoilage, manufacturers should take into consideration in their pasteurization processes the D-values and z-values either of the actual contaminants or of a model. B. fulva is a good model candidate because it has been 3, 31,32,71,72,75,83,109,111,127,128 Linear 5, 13,14,18,21,44,47,51,52,57,58,60,80,85,87,88,90,110,114,115 Two-phase linear (eq. 5)…”

“…The general pattern of this model is flexible; it allows inclusion of a large set of mathematical expressions for each gamma term ( Table 3) and addition of new gamma tenns, for example to describe the effect of an inhibitory compound (52).…”