Performance of mycological media in enumerating desiccated food spoilage yeasts: An interlaboratory study

L. R. Beuchat, E. Frändberg, T. Deák, S. M. Alzamora, J. Chen, S. Guerrero, A. López-Malo, I. Ohlsson, M. Olsen, J. M. Peinado, J. Schnurer, M. I. De Siloniz, J. Tornai-Lehoczki

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Dichloran 18% glycerol agar (DG18) was originally formulated to enumerate nonfastidious xerophilic moulds in foods containing rapidly growing Eurotium species. Some laboratories are now using DG18 as a general purpose medium for enumerating yeasts and moulds, although its performance in recovering yeasts from dry foods has not been evaluated. An interlaboratory study compared DG18 with dichloran rose bengal chloramphenicol agar (DRBC), plate count agar supplemented with chloramphenicol (PCAC), tryptone glucose yeast extract chloramphenicol agar (TGYC), acidified potato dextrose agar (APDA), and orange serum agar (OSA) for their suitability to enumerate 14 species of lyophilized yeasts. The coefficient of variation for among-laboratories repeatability within yeast was 1.39% and reproducibility of counts among laboratories was 7.1%. The order of performance of media for recovering yeasts was TGYC>PCAC=OSA>APDA>DRBC>DG18. A second study was done to determine the combined effects of storage time and temperature on viability of yeasts and suitability of media for recovery. Higher viability was retained at -18°C than at 5°C or 25°C for up to 42 weeks, although the difference in mean counts of yeasts stored at -18°C and 25°C was only 0.78 log10 cfu/ml of rehydrated suspension. TGYC was equal to PCAC and superior to the other four media in recovering yeasts stored at -18°C, 5°C, or 25°C for up to 42 weeks. Results from both the interlaboratory study and the storage study support the use of TGYC for enumerating desiccated yeasts. DG18 is not recommended as a general purpose medium for recovering yeasts from a desiccated condition.

Original languageEnglish
Pages (from-to)89-96
Number of pages8
JournalInternational Journal of Food Microbiology
Volume70
Issue number1-2
DOIs
Publication statusPublished - Oct 22 2001

Fingerprint

food spoilage
Agar
Yeasts
agar
yeasts
Chloramphenicol
chloramphenicol
Food
yeast extract
Glucose
glucose
plate count
Rose Bengal
Solanum tuberosum
molds (fungi)
Eurotium
Fungi
viability
potatoes
Serum

Keywords

  • Mycological media
  • TGYC
  • Yeast

ASJC Scopus subject areas

  • Food Science
  • Microbiology

Cite this

Performance of mycological media in enumerating desiccated food spoilage yeasts : An interlaboratory study. / Beuchat, L. R.; Frändberg, E.; Deák, T.; Alzamora, S. M.; Chen, J.; Guerrero, S.; López-Malo, A.; Ohlsson, I.; Olsen, M.; Peinado, J. M.; Schnurer, J.; De Siloniz, M. I.; Tornai-Lehoczki, J.

In: International Journal of Food Microbiology, Vol. 70, No. 1-2, 22.10.2001, p. 89-96.

Research output: Contribution to journalArticle

Beuchat, LR, Frändberg, E, Deák, T, Alzamora, SM, Chen, J, Guerrero, S, López-Malo, A, Ohlsson, I, Olsen, M, Peinado, JM, Schnurer, J, De Siloniz, MI & Tornai-Lehoczki, J 2001, 'Performance of mycological media in enumerating desiccated food spoilage yeasts: An interlaboratory study', International Journal of Food Microbiology, vol. 70, no. 1-2, pp. 89-96. https://doi.org/10.1016/S0168-1605(01)00519-0
Beuchat, L. R. ; Frändberg, E. ; Deák, T. ; Alzamora, S. M. ; Chen, J. ; Guerrero, S. ; López-Malo, A. ; Ohlsson, I. ; Olsen, M. ; Peinado, J. M. ; Schnurer, J. ; De Siloniz, M. I. ; Tornai-Lehoczki, J. / Performance of mycological media in enumerating desiccated food spoilage yeasts : An interlaboratory study. In: International Journal of Food Microbiology. 2001 ; Vol. 70, No. 1-2. pp. 89-96.
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