Preliminary studies on developing a new method for quality control of tomato purée

G. Kiskó, K. Kaffka, H. Daood

Research output: Contribution to journalArticle


In the industrial practice Howard mould count (HOWARD, 1911) is used for the estimation of mould contamination of foods. It was developed originally for the investigation of mould contamination of tomato purée. It is also used nowadays for quality control purposes for other food products as well. Recently this constitutes the basis of the acceptance of the fi nished products in international trade. This technique demands experts with a lot of practice and morphological profi ciency. The investigation makes use of eyes and so the tiredness of the investigator can cause uncertainties. The possibility of other methods for the determination of mould contamination of tomato purée was investigated to replace the Howard method. The NIR technique - as a rapid, non-destructive, reagentless and accurate method - was anticipated as a suitable method for the mentioned purpose. Canned tomato purée had been allowed to become mouldy then the sample was blended with non-mouldy samples in different ratio, so a series of tomato purées containing known amounts of mouldy purée was prepared. Howard mould counts and ergosterol content - another mould contamination relating value - was used as reference for NIR calibration. At quantitative investigation better results were obtained using ergosterol values. The best correlation coeffi cient (R=0.93) and the smallest standard error of calibration (SEC=0.008 mg g-1 ergosterol) was achieved with triangular smoothing and second derivation of the spectra. At qualitative investigation Polar Qualifi cation System (PQS) was used. Clusters between samples with low and high ergosterol levels could be separated.

Original languageEnglish
Pages (from-to)59-66
Number of pages8
JournalActa Alimentaria
Publication statusPublished - Jan 1 2011



  • Ergosterol
  • Howard mould count
  • Moulds
  • NIR

ASJC Scopus subject areas

  • Food Science

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