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Listeria Agar Base (Ottaviani & Agosti, O&A) – ALOA Compatible ISO 11290 Medium
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Selective & Differential Culture Medium · Food & Environmental Microbiology
Listeria Agar Base (Ottaviani & Agosti)
O&A Base · ALOA · Chromogenic Listeria Medium
ISO 11290-1/2:2017 AFNOR Validated FDA-BAM Ch.10 EU Reg. 2073/2005 Selective · Differential · Chromogenic
AuSaMicS
Life Science™
Cat No.
AS-1388
Format
Dehydrated Powder
Final pH
7.2 ± 0.2
Incubation
35–37 °C / 24–48 h
Standard
ISO 11290-2:2017
Overview
Listeria Agar Base (Ottaviani & Agosti, O&A) is a selective and differential chromogenic solid medium for the isolation and enumeration of Listeria species — including the food-borne pathogen Listeria monocytogenes — from food, environmental, and clinical matrices. First described by Ottaviani & Agosti (1997) and validated by AFNOR, the medium is mandated in ISO 11290-2:2017 for direct enumeration of L. monocytogenes in food products.
The base combines peptones and yeast extract to support growth of fastidious Listeria strains, while selective agents (polymyxin B, acriflavine, lithium chloride) suppress competing flora. Chromogenic indicators produce turquoise-blue to blue-green colony colouration for Listeria spp., and a characteristic opaque white halo around L. monocytogenes and L. ivanovii colonies arising from phosphatidylinositol phospholipase C (PI-PLC) activity — enabling presumptive identification directly from primary plates.
Applications
Food Safety Testing
ISO 11290-2 direct enumeration in RTE products, dairy, meat, seafood, and fresh produce. EU Regulation 2073/2005 compliance.
Environmental Monitoring
Food processing surfaces, drains, equipment, and air-sampling swabs. HACCP critical control point verification.
Clinical & Diagnostic
Isolation from CSF, blood cultures, and clinical specimens. Proficiency testing for NATA/ISO 17025-accredited laboratories.
Key Features
| Selectivity | Polymyxin B + acriflavine + LiCl suppress competing Gram-positive and Gram-negative flora |
| Differentiation | Chromogenic substrate produces turquoise / blue-green colonies for Listeria spp. |
| Halo Formation | Opaque white halo around L. monocytogenes / L. ivanovii (PI-PLC activity) |
| Nutrient Support | Peptones + yeast extract sustain growth of stressed and slow-growing Listeria strains |
| Regulatory Basis | ISO 11290-2:2017 · AFNOR validation · FDA-BAM Ch. 10 · USDA-FSIS MLG 8 · EU 2073/2005 |
| Matrix Applicability | Food (all categories), environmental swabs, clinical and water samples |
Colony Interpretation
| Organism | Colony Colour | Halo | Presumptive Result |
|---|---|---|---|
| L. monocytogenes | Turquoise to blue-green | ✓ Opaque white — PI-PLC positive | Presumptive positive |
| L. ivanovii | Turquoise to blue-green | ✓ Opaque white — PI-PLC positive | Presumptive Listeria |
| Other Listeria spp. | Turquoise to blue-green | ✗ Absent / faint | Listeria spp. (not L. mono.) |
| Non-Listeria | White, cream or inhibited | ✗ None | Not Listeria |
Confirmation required: Presumptive positive colonies must be confirmed by biochemical (API Listeria, VITEK 2) or molecular (real-time PCR, ISO 11290-1) methods before reporting.
Incubation Conditions
Standard — ISO 11290-2:2017
35–37 °C
24–48 hours · Count all turquoise/blue-green colonies
Extended / Stressed Strains
30 °C
Up to 72 hours · FDA-BAM / AFNOR protocols
Storage & Shelf Life
| Dehydrated Base | 15–30 °C, dry place, tightly closed, protected from light and humidity |
| Prepared Plates | 2–8 °C, sealed, protected from light — use within 2 weeks of preparation |
| After Opening | Reseal immediately; use desiccant sachet if ambient humidity > 60% RH |
| Do Not Use If | Powder shows caking, darkening, unusual odour, or prepared plates show discolouration |
References
1. Ottaviani F. & Agosti M. (1997). New chromogenic plating medium for the isolation and identification of Listeria monocytogenes. Industrie Alimentari, 36:1506–1510.
2. ISO 11290-1:2017 — Horizontal method for detection of Listeria monocytogenes and Listeria spp.
3. ISO 11290-2:2017 — Horizontal method for enumeration of L. monocytogenes and Listeria spp.
4. FDA-BAM Chapter 10 — Detection and Enumeration of Listeria monocytogenes.
5. EU Commission Regulation (EC) No. 2073/2005 — Microbiological criteria for foodstuffs.
AuSaMicS Pty Ltd (ABN 56 676 640 467) warrants that this product meets stated specifications at time of manufacture. For laboratory use only. Not intended for human, animal, food, feed, or pharmaceutical use. · 31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
Product Identification
| Product Name | Listeria Agar Base (O&A) |
| Abbreviation | ALOA Base; O&A Base |
| Catalog No. | AS-1388 |
| Lot No. | LAB260301 |
| Mfg. Date | March 2026 |
| Retest Date | March 2028 |
| Grade | Microbiological / Selective-Differential |
| Standard | ISO 11290-2:2017 · AFNOR |
Physical Properties
| Appearance (powder) | Homogeneous, free-flowing; cream to light beige |
| Appearance (prepared) | Clear to slightly opalescent; light amber gel |
| Odour | Faint, characteristic (peptone/yeast) |
| pH (prepared, 25 °C) | 7.2 ± 0.2 |
| Agar gel / melt | Gels ~32–34 °C / Melts ~84–86 °C |
| Loss on Drying | ≤ 7.0% w/w (105 °C / 2 h) |
Composition per Litre
| Component | Function | Amount (g/L) |
|---|---|---|
| Peptone / Proteose Peptone | Nitrogen, amino acids — primary nutrient source | 10.00 |
| Yeast Extract | Vitamins, growth factors — supports fastidious strains | 5.00 |
| Sodium Chloride | Osmotic balance — maintains cell turgor | 5.00 |
| Agar (bacteriological grade) | Solidifying agent | 15.00 |
| Polymyxin B sulfate | Suppresses Gram-negative competing flora | Per validated formulation |
| Acriflavine | Suppresses Gram-positive competing flora | Per validated formulation |
| Lithium Chloride | Selective agent — inhibits enterococci and other flora | Per validated formulation |
| Chromogenic / differential indicators | Produces turquoise/blue-green colonies for Listeria spp. | Per validated formulation |
| Purified water | Solvent | q.s. to 1 L |
Preparation Protocol
- 1Suspend the dehydrated base medium in 1 L of purified / distilled water.
- 2Heat with frequent agitation until completely dissolved. Bring to a full boil for 1 minute.
- 3Autoclave at 121 °C (15 psi) for 15 minutes. Do not over-autoclave.
- 4Cool to 45–50 °C in a water bath before adding heat-labile supplements.
- 5Add selective agents and/or chromogenic supplements aseptically if not pre-incorporated in base.
- 6Pour 15–20 mL per 90 mm Petri dish under laminar flow. Allow to set on a level surface.
- 7Dry plates at 37 °C for 30 min or RT for 1 h before use. Store at 2–8 °C.
Incubation & Interpretation
Standard — ISO 11290-2:2017
35–37 °C
24–48 hours
Extended / Stressed Strains
30 °C
Up to 72 hours · FDA-BAM / AFNOR
| L. monocytogenes / L. ivanovii | Turquoise to blue-green colonies with opaque white halo (PI-PLC+) |
| Other Listeria spp. | Turquoise to blue-green colonies without halo |
| Non-Listeria | Inhibited or atypical colour; no blue-green colouration |
| Confirmation | Biochemical (API Listeria, VITEK) or molecular (PCR) testing required for definitive ID |
Quality Control Specifications
| Parameter | Specification | Method |
|---|---|---|
| Appearance (powder) | Homogeneous; cream to beige; no lumps | Visual inspection |
| pH (prepared, 25 °C) | 7.0 – 7.4 | Potentiometry (ISO 10523) |
| Loss on Drying | ≤ 7.0% w/w | 105 °C / 2 h (gravimetric) |
| Growth — L. monocytogenes ATCC 19115 | Good growth; turquoise-blue + white halo | ISO 11290-2 growth test |
| Growth — L. innocua ATCC 33090 | Good growth; turquoise-blue; no halo | ISO 11290-2 growth test |
| Inhibition — E. coli ATCC 25922 | Complete / ≥ 99% inhibition | AFNOR performance test |
| Inhibition — E. faecalis ATCC 29212 | Complete / ≥ 99% inhibition | AFNOR performance test |
| Sterility (prepared medium) | No growth at 14 days (30–35 °C) | Incubation sterility check |
Technical References
| Primary Reference | Ottaviani & Agosti (1997). Industrie Alimentari, 36:1506–1510 |
| ISO Standards | ISO 11290-1:2017 & ISO 11290-2:2017 — Listeria monocytogenes detection / enumeration |
| FDA Method | FDA Bacteriological Analytical Manual, Chapter 10 |
| USDA Method | USDA-FSIS Microbiology Laboratory Guidebook (MLG) 8 |
| EU Regulation | Commission Regulation (EC) No. 2073/2005 — Microbiological criteria for foodstuffs |
AuSaMicS Pty Ltd (ABN 56 676 640 467) · 31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
Safety Data Sheet — GHS Format (Australian WHS Regulations 2017)
Prepared in accordance with the Work Health and Safety (WHS) Regulations and GHS 7th Revision. Issue Date: March 2026 · Rev: 1.0
Prepared in accordance with the Work Health and Safety (WHS) Regulations and GHS 7th Revision. Issue Date: March 2026 · Rev: 1.0
Hazard Notice: This medium contains acriflavine (suspected mutagen, H341) and lithium chloride (harmful if swallowed, H302). Handle with appropriate PPE. Minimise dust exposure. See Sections 2, 8, and 11.
Section 1 — Identification
| Product Name | Listeria Agar Base (Ottaviani & Agosti) |
| Other Names | ALOA Base; Chromogenic Listeria Agar Base; Agar O&A |
| Catalog No. | AS-1388 |
| Intended Use | Selective microbiological culture medium — for laboratory use only |
| Supplier | AuSaMicS Pty Ltd, 31 Longview CT, Thomastown VIC 3074, Australia |
| ABN | 56 676 640 467 |
| Phone | +61 412 520 598 |
| Email / Web | support@ausamics.com / www.ausamics.com.au |
| Emergency (24h) | Poisons Information Centre: 13 11 26 (Australia) |
Section 2 — Hazard Identification
⚠️
WARNING
H302 Harmful if swallowed (LiCl) · H315 Causes skin irritation · H317 May cause allergic skin reaction (acriflavine) · H319 Causes serious eye irritation · H335 May cause respiratory irritation · H341 Suspected of causing genetic defects (acriflavine — Cat. 2)
| GHS Classification | Harmful (H302, H317, H319, H335); Suspected Mutagen Cat. 2 (H341 — acriflavine component) |
| Signal Word | WARNING |
| Precautionary Stmts. | P260 · P264 · P270 · P272 · P280 · P301+P312 · P333+P313 · P501 |
| Other Hazards | Polymyxin B: potential sensitiser and nephrotoxic at systemic doses. Minimise all exposure. |
Section 3 — Composition
| Component | CAS No. | Proportion (w/w) | GHS Classification |
|---|---|---|---|
| Agar (bacteriological) | 9002-18-0 | ~42.9% | Not classified |
| Peptone / Proteose Peptone | — | ~28.6% | Not classified |
| Yeast Extract | 8013-01-2 | ~14.3% | Not classified |
| Sodium Chloride | 7647-14-5 | ~14.3% | Not classified |
| Lithium Chloride | 7447-41-8 | < 1.0% | H302 · H315 · H319 · H335 |
| Acriflavine | 65589-04-0 | < 0.5% | H317 · H341 (susp. mutagen Cat. 2) |
| Polymyxin B sulfate | 1405-20-5 | < 0.1% | H315 · H317 · H319 |
| Chromogenic indicators | Proprietary | < 1.0% | Not classified at supplied concentration |
Section 4 — First Aid Measures
| Inhalation | Remove to fresh air. If respiratory irritation persists seek medical advice. Acriflavine dust: avoid repeated inhalation — suspected mutagen. |
| Skin Contact | Wash immediately with soap and water for at least 15 minutes. Remove contaminated clothing. Seek medical advice if redness, itching, or rash develops (acriflavine sensitisation). |
| Eye Contact | Rinse immediately with copious water for at least 15 minutes, holding eyelids open. Seek prompt medical attention. |
| Ingestion | Do not induce vomiting. Rinse mouth. Seek medical advice — LiCl may cause nausea, diarrhoea, and CNS effects at elevated doses. Contact Poisons Centre: 13 11 26. |
| Medical Note | Document acriflavine exposure (mutagenicity potential). Polymyxin B: potential renal and neurological effects at high systemic dose. Show SDS to physician. |
Section 5 — Fire-Fighting Measures
| Flash Point | Not applicable (non-flammable powder) |
| Extinguishing Media | CO², dry chemical, or water spray suitable for surrounding fire |
| Hazardous Combustion | CO, CO², HCl, nitrogen oxides, acriflavine decomposition products |
| Fire-Fighting PPE | SCBA and full protective clothing |
Section 6 — Accidental Release
| Personal Precautions | Avoid dust. Wear nitrile gloves, P2 mask, safety goggles. Ensure adequate ventilation. |
| Environmental | Prevent entry to drains and waterways. Acriflavine is toxic to aquatic organisms. |
| Clean-up | Collect with HEPA vacuum or damp cloth. Avoid dry sweeping. Dispose per Section 13. |
Section 7 — Handling and Storage
| Handling | Ventilated laboratory. Avoid dust inhalation, skin and eye contact. Wear PPE. Do not eat, drink, or smoke. Acriflavine: minimise exposure — potential mutagen (ALARA principle). |
| Storage — Dehydrated | 15–30 °C, dry, tightly closed, protected from light and humidity |
| Storage — Prepared | 2–8 °C, sealed, protected from light; use within 2 weeks |
| Incompatibilities | Strong oxidising agents; concentrated acids and bases; reducing agents |
Section 8 — Exposure Controls / PPE
| OEL (Safe Work Australia) | No specific WES for acriflavine — apply ALARA. LiCl: no specific WES. |
| Engineering Controls | Fume cupboard or local exhaust ventilation when weighing or handling powder |
| Respiratory | P2 / FFP2 dust mask mandatory when generating dust |
| Hand Protection | Nitrile gloves (EN 374 / AS/NZS 2161) — change immediately if contaminated |
| Eye / Face | Splash goggles; safety glasses minimum |
| Body Protection | Lab coat, closed footwear; impermeable apron when pouring volumes |
Section 9 — Physical and Chemical Properties
| Property | Value |
|---|---|
| Physical State (25 °C) | Solid (powder) |
| Colour | Cream to light beige |
| Odour | Faint, characteristic (peptone/yeast) |
| pH (prepared, 25 °C) | 7.2 ± 0.2 |
| Melting / Solidification (agar) | Gels ~32–34 °C / Melts ~84–86 °C |
| Flash Point | Not applicable |
| Vapour Pressure | Negligible |
| Solubility | Dissolves completely on heating with agitation |
| Explosive / Oxidising | Not explosive; not oxidising |
Section 10 — Stability and Reactivity
| Stability | Stable under recommended storage conditions |
| Conditions to Avoid | Moisture, heat > 40 °C, direct sunlight, humidity > 70% RH |
| Materials to Avoid | Strong oxidising agents; concentrated acids and bases |
| Hazardous Decomposition | CO, CO², HCl, NOx, acriflavine degradation products on combustion |
Section 11 — Toxicological Information
| Acute Oral Toxicity | Moderate concern — LiCl component; harmful if swallowed (H302) |
| Skin Irritation | H315 — may cause skin irritation (LiCl, polymyxin B) |
| Eye Irritation | H319 — causes serious eye irritation |
| Skin Sensitisation | H317 — acriflavine may cause allergic skin reaction |
| Mutagenicity | H341 — acriflavine: suspected of causing genetic defects (Cat. 2). Minimise all exposure; apply ALARA. |
| Carcinogenicity | Not classified at supplied concentrations in formulated medium |
| Reproductive Toxicity | Not classified |
| STOT (single) | H335 — may cause respiratory irritation (LiCl) |
Section 12 — Ecological Information
| Aquatic Toxicity | Acriflavine is toxic to aquatic organisms — prevent any release to waterways |
| Biodegradability | Agar, peptones, yeast extract: biodegradable. Acriflavine: limited data; treat as persistent. |
| Bioaccumulation | Not expected for major components |
| PBT / vPvB | Not determined |
Section 13 — Disposal
| Waste Classification | Treat as hazardous laboratory waste due to acriflavine content (suspected mutagen) |
| Prepared Medium (used) | Autoclave at 121 °C / 30 min before disposal. Treat as biohazardous waste. |
| Prepared Medium (unused) | Autoclave or chemically inactivate. Dispose via licensed contractor. |
| Dehydrated Powder | Dispose as hazardous chemical waste via licensed contractor |
| Containers | Decontaminate before disposal. Do not reuse for food or beverage. |
Section 14 — Transport
| UN Number | Not regulated as dangerous goods in standard laboratory quantities |
| ADG (Australia) | Not classified as dangerous goods |
| IATA / ICAO | Not restricted at supplied concentrations |
| IMDG | Not classified — check local regulations for large commercial shipments |
Section 15 — Regulatory Information
| AICS (Australia) | All components listed on the Australian Inventory of Chemical Substances |
| SUSMP Schedule | Acriflavine Schedule 4 (Appendix D) when used therapeutically — supplied for laboratory use only |
| WHS Regulations | Mixture contains hazardous chemicals (acriflavine, LiCl) — WHS Regulations 2017 apply |
| REACH (EU) | Components comply with REACH Regulation (EC) No. 1907/2006 |
Section 16 — Other Information
| SDS Prepared By | AuSaMicS Pty Ltd — Technical & Quality Department |
| Issue Date | March 2026 · Rev 1.0 |
| Review Date | March 2027 or upon regulatory change |
| Key References | Safe Work Australia Code of Practice; GHS 7th Rev.; ISO 11290-2:2017; WHS Regulations 2017 |
AuSaMicS Pty Ltd (ABN 56 676 640 467) · 31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
This SDS is prepared in accordance with Australian WHS Regulations and GHS (7th Rev.). For laboratory use only.
This SDS is prepared in accordance with Australian WHS Regulations and GHS (7th Rev.). For laboratory use only.
Product Details
| Product Name | Listeria Agar Base (O&A) |
| Catalog No. | AS-1388 |
| Lot No. | LAB260301 |
| Mfg. Date | March 2026 |
| Retest Date | March 2028 |
| Grade | Microbiological / Selective-Differential |
| Standard | ISO 11290-2:2017 · AFNOR |
Document Information
| COA No. | COA-AS-1388-L001 |
| Issue Date | March 2026 |
| Issued By | AuSaMicS Quality Control |
| Test Ref. | ISO 11290-2 / AFNOR |
Test Results & Analytical Data
| Test Parameter | Specification | Method | Result | Status |
|---|---|---|---|---|
| Appearance (powder) | Homogeneous; cream to beige; no lumps or darkening | Visual inspection | Conforms | PASS |
| Appearance (prepared medium) | Clear to slightly opalescent; light amber gel | Visual — plate check | Conforms | PASS |
| pH (prepared, 25 °C) | 7.0 – 7.4 | Potentiometry (ISO 10523) | 7.2 | PASS |
| Gel strength (prepared) | Firm, clear gel; no syneresis or collapse | Visual — plate check | Firm, clear | PASS |
| Loss on Drying | ≤ 7.0% w/w | 105 °C / 2 h (gravimetric) | 3.5% | PASS |
| Growth — L. monocytogenes ATCC 19115 | Good growth; turquoise-blue colonies + opaque white halo | ISO 11290-2 growth test | Conforms | PASS |
| Growth — L. innocua ATCC 33090 | Good growth; turquoise-blue colonies; no halo | ISO 11290-2 growth test | Conforms | PASS |
| Inhibition — E. coli ATCC 25922 | Complete inhibition (≥ 99%) | AFNOR performance test | Complete | PASS |
| Inhibition — E. faecalis ATCC 29212 | Complete inhibition (≥ 99%) | AFNOR performance test | Complete | PASS |
| Sterility (prepared medium) | No growth at 14 days (30–35 °C) | Incubation check | No growth | PASS |
| ISO 11290-2:2017 Compliance | Full conformance with formula and performance criteria | Compositional + performance review | Conforms | CONFORM |
Conclusion: Lot LAB260301 has been tested against all specifications and fully meets the requirements of ISO 11290-2:2017 and AFNOR validation criteria for Listeria Agar Base (O&A). This lot is RELEASED for use.
Quality Control Analyst
AuSaMicS Quality Control Department
Date: March 2026 | Signature: _______________
Quality Manager
AuSaMicS Pty Ltd
Date: March 2026 | Signature: _______________
AuSaMicS Pty Ltd (ABN 56 676 640 467) warrants that this product meets the specifications stated in this Certificate of Analysis at time of manufacture and release. For laboratory and research use only. Not intended for human, animal, food, feed, or pharmaceutical use. AuSaMicS Pty Ltd shall not be held liable for any direct, indirect, incidental, or consequential damages resulting from use outside the intended application. · 31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
AuSaMicS Pty Ltd · ABN 56 676 640 467 · 31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au