Efficacy of natamycin for control of growth and ochratoxin A production by Aspergillus carbonarius strains under different environmental conditions
Article first published online: 20 JUL 2007
Journal of Applied Microbiology
Volume 103, Issue 6, pages 2234–2239, December 2007
How to Cite
Medina, Á., Jiménez, M., Mateo, R. and Magan, N. (2007), Efficacy of natamycin for control of growth and ochratoxin A production by Aspergillus carbonarius strains under different environmental conditions. Journal of Applied Microbiology, 103: 2234–2239. doi: 10.1111/j.1365-2672.2007.03462.x
- Issue published online: 20 JUL 2007
- Article first published online: 20 JUL 2007
- 2007/0221: received 13 February 2007, revised 17 April 2007 and accepted 4 May 2007
- Aspergillus carbonarius;
- environmental factors;
- grape-based products;
- mould growth;
- mycotoxigenic fungi;
- natural preservatives
Aims: To examine the efficacy of natamycin produced by Streptomyces natalensis against strains of Aspergillus carbonarius growth and ochratoxin A (OTA) production under different environmental factors on a grape juice-based medium.
Methods and Results: Detailed studies in the range 0–20 ng ml−1 for control of growth and ochratoxin production by strains of A. carbonarius at 0·98, 0·96 and 0·94 water availabilities (aw) and 15–25°C on a fresh red grape extract medium were examined. Inhibition of growth was depending on temperature and aw level. At 15°C, 5–10 ng ml−1 natamycin was effective in reducing growth almost completely. However, at 20–25°C and all the three aw levels, growth was only slightly inhibited by 5–10 ng ml−1 natamycin. There were strain differences with regard to inhibition of OTA production. At 15°C and 0·98 aw, 10 ng ml−1 was required to inhibit production by >90%. However, at 0·96 and 0·94 aw, almost complete inhibition occurred. At 20°C, OTA production was only significantly inhibited by 10 ng ml−1 natamycin at 0·94 aw. At 0·96 and 0·98 aw, some inhibition occurred with 5–10 ng ml−1, but greater concentrations would be required for effective inhibition. At 25°C, 5 ng ml−1 was effective at all aw levels. However, at 15°C and 25°C and a wide range of aw levels, natamycin effectively controlled OTA production.
Conclusions: Natamycin appears to be a very effective for controlling growth and OTA production by strains of A. carbonarius over a range of aw and temperature conditions on grape-based media.
Significance and Impact of the Study: This is the first detailed study to demonstrate the impact of natamycin against A. carbonarius. This study suggests that use of natamycin at 50–100 ng ml−1 can give complete inhibition of growth of A. carbonarius and OTA production over a range of environmental conditions. Natamycin could be an important component of a system to prevent OTA contamination of wine as well during the drying and production of vine fruits.