Primary Listeria Agar

Primary Listeria Agar

PP7025 Primary Listeria Agar is a selective medium for the isolation, enumeration and presumptive identification of Listeria species and L. monocytogenes from food and environmental samples.

Listeria monocytogenes is commonly found in soil, sewage, and faeces. It is difficult to eradicate, and can cause serious food poisoning; therefore, L. monocytogenes is frequently tested for in food processing facilities to avoid contamination. Contamination can occur at all steps of the food manufacturing chain from raw materials to point of consumption.

Primary Listeria Agar is used for the detection and presumptive identification of Listeria spp. and the specific differentiation of L. monocytogenes. Based on the method of Ottaviani et al (1 2), this medium allows detection and enumeration of Listeria spp. as early as 24 hours. Primary Listeria Agar is recommended by ISO 11290-1:2017 (3) and ISO 11290-2:2017 (4) and tested in accordance with ISO 11133:2014 (5).

  1. Ottaviani, F., Ottaviani, M., and Agosti M. (1997) Differential agar medium for Listeria monocytogenes. Quimper Froid Symposium Proceedings, P6 ADRIA Quimper, France, 16-18 June.
  2. Ottaviani, F., Ottaviani, M.G., and Agosti, M. (1997). Esperienze su un agar selettivo e differenziale per Listeria monocytogenes. Industrie Alimentari, 36: 888-889.
  3. International Organization for Standardization (2017) 11290-1:2017 Microbiology of the food chain – Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. – Part 1: Detection method. Geneva, ISO.
  4. International Organization for Standardization (2017) 11290-2:2017 Microbiology of the food chain – Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. – Part 2: Enumeration method. Geneva, ISO.
  5. International Organization for Standardization (2014) 11133:2014 Microbiology of food, animal feed and water – Preparation, production, storage and performance testing of culture media. Geneva, ISO.

Additional Information

Container

Pack Size

Shelf Life (days)

Storage

Appearance

Firm Gel

Colour

Straw

Recommended Incubation

Aerobically at 37±1°C for 24-48 hours

pH

Volume

Product Description

Organisms Ref. No Result
L. monocytogenes NCTC 11994 Growth: Blue/green colonies with halo
L. monocytogenes NCTC 7973 Growth: Blue/green colonies with halo
L. innocua NCTC 11288 Growth: Blue/green colonies with NO halo
E. coli NCTC 12241 Inhibited
E. coli ATCC 8739 Inhibited
E. faecalis NCTC 12697 Inhibited
E. faecalis NCTC 775 Inhibited

Incubate aerobically at 37 ± 1°C for 24-48 hours.

Formula*

Formula*

Enzymatic digest of animal tissue
Enzymatic digest of casein
Yeast extract
Agar
Lecithin
Stabilisers
Sodium pyruvate
Glucose
Magnesium glycerophosphate
Magnesium sulphate
Sodium chloride
Lithium chloride
Disodium hydrogen phosphate
5-Bromo-4-chloro-3-indolyl-ß-Dglucopyranoside
18.0
6.0
10.0
12.0
40.0
4.0
2.0
2.0
1.0
0.5
5.0
10.0
2.5
0.05
*Adjusted/supplemented as needed to meet performance requirements