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Enumeration of starter cultures during yogurt production using Petrifilm AC plates associated with acidified MRS and M17 broths.
J Dairy Res. 2009 May; 76(2):229-33.JD

Abstract

The efficiency of Petrifilm AC (3M Microbiology, St. Paul, MN, USA) associated with the broths M17 and de Mann-Rogosa-Sharpe (MRS) at pH 5.4 was evaluated to enumerate Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus during the yogurt production. Commercial and reference strains of these microorganisms were experimentally inoculated in nonfat milk and incubated at 42 degrees C for 4 h for yogurt production. At the moment of inoculation and after incubation, aliquots were collected, submitted to dilution using the broths M17 and MRS at pH 5.4, and plated for Strep. salivarius and Lb. bulgaricus enumeration according ISO 9232 and at Petrifilm AC plates, respectively. M17 plates were incubated at 42 degrees C, and MRS plates were incubated at 35 degrees C under anaerobiosis. After 48 h, the formed colonies were enumerated and the counts were compared by correlation and analysis of variance (P<0.05). In addition, colonies were randomly selected from all plates and characterized according to Gram staining and morphology. The obtained results indicated that Petrifilm AC plates associated to M17 and MRS at pH 5.4 can be considered as a suitable alternative for Strep. salivarius and Lb. bulgaricus enumeration during yogurt production, with slight interferences due to the acidity of MRS at the moment of inoculation, and due to the acidity of yogurt at the end of fermentation process. It was also observed that the MRS at pH 5.4 was not sufficiently selective for Lb. delbrueckii enumeration, despite it is indicated by the official protocol from ISO 9232.

Authors+Show Affiliations

Departamento de Tecnologia de Alimentos, Centro de Ciências Exatas, Universidade Federal de Viçosa, Viçosa MG, Brasil.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19281634

Citation

Gonçalves, Marília M., et al. "Enumeration of Starter Cultures During Yogurt Production Using Petrifilm AC Plates Associated With Acidified MRS and M17 Broths." The Journal of Dairy Research, vol. 76, no. 2, 2009, pp. 229-33.
Gonçalves MM, Freitas R, Nero LA, et al. Enumeration of starter cultures during yogurt production using Petrifilm AC plates associated with acidified MRS and M17 broths. J Dairy Res. 2009;76(2):229-33.
Gonçalves, M. M., Freitas, R., Nero, L. A., & Carvalho, A. F. (2009). Enumeration of starter cultures during yogurt production using Petrifilm AC plates associated with acidified MRS and M17 broths. The Journal of Dairy Research, 76(2), 229-33. https://doi.org/10.1017/S0022029909003975
Gonçalves MM, et al. Enumeration of Starter Cultures During Yogurt Production Using Petrifilm AC Plates Associated With Acidified MRS and M17 Broths. J Dairy Res. 2009;76(2):229-33. PubMed PMID: 19281634.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Enumeration of starter cultures during yogurt production using Petrifilm AC plates associated with acidified MRS and M17 broths. AU - Gonçalves,Marília M, AU - Freitas,Rosangela, AU - Nero,Luís A, AU - Carvalho,Antônio F, Y1 - 2009/03/13/ PY - 2009/3/14/entrez PY - 2009/3/14/pubmed PY - 2009/7/2/medline SP - 229 EP - 33 JF - The Journal of dairy research JO - J Dairy Res VL - 76 IS - 2 N2 - The efficiency of Petrifilm AC (3M Microbiology, St. Paul, MN, USA) associated with the broths M17 and de Mann-Rogosa-Sharpe (MRS) at pH 5.4 was evaluated to enumerate Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus during the yogurt production. Commercial and reference strains of these microorganisms were experimentally inoculated in nonfat milk and incubated at 42 degrees C for 4 h for yogurt production. At the moment of inoculation and after incubation, aliquots were collected, submitted to dilution using the broths M17 and MRS at pH 5.4, and plated for Strep. salivarius and Lb. bulgaricus enumeration according ISO 9232 and at Petrifilm AC plates, respectively. M17 plates were incubated at 42 degrees C, and MRS plates were incubated at 35 degrees C under anaerobiosis. After 48 h, the formed colonies were enumerated and the counts were compared by correlation and analysis of variance (P<0.05). In addition, colonies were randomly selected from all plates and characterized according to Gram staining and morphology. The obtained results indicated that Petrifilm AC plates associated to M17 and MRS at pH 5.4 can be considered as a suitable alternative for Strep. salivarius and Lb. bulgaricus enumeration during yogurt production, with slight interferences due to the acidity of MRS at the moment of inoculation, and due to the acidity of yogurt at the end of fermentation process. It was also observed that the MRS at pH 5.4 was not sufficiently selective for Lb. delbrueckii enumeration, despite it is indicated by the official protocol from ISO 9232. SN - 1469-7629 UR - https://www.unboundmedicine.com/medline/citation/19281634/Enumeration_of_starter_cultures_during_yogurt_production_using_Petrifilm_AC_plates_associated_with_acidified_MRS_and_M17_broths_ L2 - https://www.cambridge.org/core/product/identifier/S0022029909003975/type/journal_article DB - PRIME DP - Unbound Medicine ER -