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 language | English |
|---|---|
| Pages (from-to) | 89-96 |
| Number of pages | 8 |
| Journal | International Journal of Food Microbiology |
| Volume | 70 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - Oct 22 2001 |
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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 journal › Article
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TY - JOUR
T1 - Performance of mycological media in enumerating desiccated food spoilage yeasts
T2 - An interlaboratory study
AU - Beuchat, L. R.
AU - Frändberg, E.
AU - Deák, T.
AU - Alzamora, S. M.
AU - Chen, J.
AU - Guerrero, S.
AU - López-Malo, A.
AU - Ohlsson, I.
AU - Olsen, M.
AU - Peinado, J. M.
AU - Schnurer, J.
AU - De Siloniz, M. I.
AU - Tornai-Lehoczki, J.
PY - 2001/10/22
Y1 - 2001/10/22
N2 - 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.
AB - 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.
KW - Mycological media
KW - TGYC
KW - Yeast
UR - http://www.scopus.com/inward/record.url?scp=0035934919&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035934919&partnerID=8YFLogxK
U2 - 10.1016/S0168-1605(01)00519-0
DO - 10.1016/S0168-1605(01)00519-0
M3 - Article
C2 - 11759766
AN - SCOPUS:0035934919
VL - 70
SP - 89
EP - 96
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
SN - 0168-1605
IS - 1-2
ER -