PLATE COUNT SKIMMED MILK AGAR

General description

Plate Count skimmed milk agar is a non-selective medium for the enumeration of viable micro-organisms in milk and dairy products. The medium does not contain any inhibitors or indicators, and it is relatively rich in nutrients. The added skimmed milk is also free from inhibitory substances. The enzymatic digest of casein (tryptone) is a nitrogen source containing a high level of free amino acids, and yeast extract supplies the B-complex vitamins. Glucose provides an energy source for the growth of bacteria, while agar is the solidifying agent.

Application

Plate Count skimmed milk agar is suitable for the determination of the total microbial content from milk and dairy products.

Features and Benefits

• GranuCult^® offers superior granulated culture media
• Safe and sustainable due to reduced risks associated with fine dust and toxic substance inhalation, resulting in a safer work environment
• Excellent wettability, solubility, and free-flowing properties
• Convenient, with minimal component separation and clumping, even under warm or humid conditions
• High batch-to-batch reproducibility
• Prolonged shelf life of up to five years
• High number of test strains exceeding all regulatory demands
• Granulation technology allows many supplements to be included, with no need to add these separately

Analysis Note

Appearance (clearness): clear to opalescent
Appearance (colour): yellowish to yellowish-brown
pH-value (25 °C): 6.8 - 7.2
Solidification behaviour (2 hrs., 40 °C): liquid
Solidification behaviour (4 hrs., 45 °C): liquid
Growth promotion test in accordance with the current version of DIN EN ISO 11133.
Inoculum on reference medium (Staphylococcus aureus ATCC 6538 (WDCM 00032)):
Inoculum on reference medium (Staphylococcus aureus ATCC 25923 (WDCM 00034)):
Inoculum on reference medium (Escherichia coli ATCC 8739 (WDCM 00012)):
Inoculum on reference medium (Escherichia coli ATCC 25922 (WDCM 00013)):
Inoculum on reference medium (Bacillus subtilis ATCC 6633 (WDCM 00003)):
Colony count (Staphylococcus aureus ATCC 6538 (WDCM 00032)):
Colony count (Staphylococcus aureus ATCC 25923 (WDCM 00034)):
Colony count (Escherichia coli ATCC 8739 (WDCM 00012)):
Colony count (Escherichia coli ATCC 25922 (WDCM 00013)):
Colony count (Bacillus subtilis ATCC 6633 (WDCM 00003)):
Recovery on test medium (Staphylococcus aureus ATCC 6538 (WDCM 00032)): ≥ 70 %
Recovery (Staphylococcus aureus ATCC 25923 (WDCM00034)): ≥ 70 %
Recovery on test medium (Escherichia coli ATCC 8739 (WDCM 00012)): ≥ 70 %
Recovery on test medium (Escherichia coli ATCC 25922 (WDCM 00013)): ≥ 70 %
Recovery on test medium (Bacillus subtilis ATCC 6633 (WDCM 00003)): ≥ 70 %
Incubation: 72 ± 3 hours at 30 ± 1 °C aerobic.
A recovery rate of 70 % is equivalent to a productivity value of 0.7.
The indicated colony counts result from the sum of a triple determination.
Reference media: Tryptic Soy Agar

Footnote

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany