Plate Count Agar (PCA) - BioReagent

Cat. No.: P1528375

GRADE & PURITY BioReagent, Suitable for microbiology

Storage

Room temperature

Shipped In

Normal

Application

Microbial culture

Overview

Plate Count Agar (PCA) is a general-purpose medium for microbial examination. It is suitable for the enumeration of total aerobic bacterial colonies in food, water and environmental samples. After dilution and plate spreading, the samples are incubated at 36 ℃. The microbial load of samples is calculated by counting colonies.

Medium Formula (per liter):

Component	Content
Tryptone	5.0 g
Yeast Extract	2.5 g
Dextrose	1.0 g
Agar	15.0 g

Instructions for Use:

Weigh 23.5 g of this product into 1 L of distilled or deionized water (the preparation volume can be scaled up or down proportionally). Heat and boil until completely dissolved, dispense into containers, and autoclave at 121°C for 15 minutes. After sterilization, mix well to prevent agar from depositing at the bottom of the vessel and solidification, then set aside for use.

Precautions:

1. pH 7.0±0.2 (at 25°C).

2. Avoid direct contact with skin and eyes during operation. In case of accidental contact, rinse immediately with plenty of clean water.

3. This product is only for laboratory research and experiments, and shall not be used for clinical diagnosis.

Specifications

Specifications & Purity

BioReagent, Suitable for microbiology

Storage

Room temperature

Shipped In

Normal

Grade

BioReagent, Suitable for microbiology

Product Line

Biological Products

Application Protocols

The steps below provide a general, literature-based protocol for preparing PCA plates and performing plate counts. Always follow your validated method and the instructions on the product label.

A. Medium preparation (general):

• Weigh the manufacturer’s recommended mass per liter of dehydrated PCA. Not specified for this item; refer to label/CoA.
• Add to appropriate volume of purified water with stirring. Heat to dissolve; bring to a gentle boil until the solution is uniform.
• Autoclave at 121 °C for 15 min (liquid cycle). After sterilization, cool to 45–50 °C.
• For pour plates: Dispense 12–15 mL per 90 mm plate. For spread plates: Pour plates ahead of time, allow to solidify and dry agar surface before use (e.g., 30–60 min in a laminar flow hood).

B. Sample processing (general):

• Prepare serial 10-fold dilutions in a suitable diluent. Target 25–250 CFU/plate for accurate counting.
• Pour plate: Pipette sample aliquot into sterile Petri dish, add molten PCA (45–50 °C), swirl gently, allow to solidify, then invert and incubate.
• Spread plate: Spread sample over surface of pre-solidified PCA using a sterile spreader; allow absorption, then invert and incubate.

C. Incubation and counting (examples):

• Incubate per method (e.g., 30 °C for 48–72 h or 35 °C for ~48 h; literature). Count plates within countable range; report CFU/g or CFU/mL considering dilution factors.

Biological Roles

This product has no intrinsic biological role as a molecule; rather, it functions as a nutrient and solid support matrix to facilitate growth of aerobic heterotrophic bacteria for enumeration.

General/literature context:

• Nutrient base: Casein/soy peptones and yeast extract (typical PCA components) provide amino acids, peptides, vitamins, and growth factors supporting a broad spectrum of non-fastidious bacteria.
• Energy source: Carbohydrates (often dextrose) supply a readily metabolizable carbon source to promote colony development within typical incubation windows.
• Solid matrix: Agar forms a porous hydrogel enabling diffusion of nutrients and oxygen, while immobilizing colonies for discrete counting.
• Methodological role: PCA is widely referenced in standard methods (e.g., ISO 4833 series for food microbiology; various national compendia) for total aerobic plate counts, aiding in hygiene assessment, shelf-life studies, and process control. Always adhere to the specific standard required by your application.

Selectivity: PCA is a non-selective, non-differential medium; it does not include inhibitors or indicators in its classic formulation (literature). As such, it supports diverse bacterial communities, yielding total counts rather than species identification.

Buffer Applications

Not typically applicable. Plate Count Agar is a culture medium, not a buffering reagent. While the prepared medium exhibits a defined pH for optimal microbial growth (typical literature value around neutral), it is not used to prepare buffer systems for biochemical assays. For buffering needs, select dedicated buffer components (e.g., phosphate, Tris) detailed under those specific products.

Green Alternatives

PCA is inherently water-based and used at modest concentrations, offering a comparatively benign environmental profile relative to solvent-intensive laboratory processes. Nevertheless, sustainability considerations remain relevant.

Greener aspects (general):

• Water as the sole solvent for preparation; no organic solvents required.
• Agar is a renewable, biobased gelling agent derived from seaweed.

Opportunities for improvement:

• Energy use: Autoclaving and maintaining molten agar consume energy. Batch scheduling, insulated water baths, and minimizing hold times can reduce energy consumption.
• Waste reduction: Prepare only the volume needed; unused molten agar can often be held at ~50 °C for limited times, but extended holding degrades performance, leading to waste.
• Reusable glassware vs disposable plastics: Consider glass Petri dishes where appropriate and validated cleaning/sterilization is feasible.

Comparison (general):

• Ready-to-use plates: Reduce in-lab energy/autoclave cycles but increase shipping volume and packaging waste.
• Alternative enumeration media: Media like R2A or TSA are not inherently “greener”; selection should be based on method performance. Optimization of incubation temperatures/times and efficient sample batching can have a larger sustainability impact than media choice.

Pharmaceutical Uses

No therapeutic or clinical claims are made. In pharmaceutical and personal care manufacturing contexts, PCA is used as a microbiological quality control medium for environmental monitoring and bioburden testing, where permitted by the governing method.

General/literature context:

• Enumeration of aerobic microbial bioburden on raw materials, in-process samples, and final products that are amenable to non-selective plating. Some compendial methods may prefer media such as TSA for total aerobic microbial count; the choice of PCA vs TSA should follow the validated method (e.g., USP/Ph. Eur./JP chapters on microbial enumeration tests).
• Utilities and environmental monitoring: Used for surface or air sampling (with swabs/contact plates/settle plates) when validated for the specific application. For compressed gases or water systems, alternative media and incubation regimens may be prescribed.

Validation considerations:

• Growth promotion testing with compendial challenge organisms (e.g., Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis) per relevant chapters.
• Method suitability/neutralization studies when test articles contain antimicrobial substances.

Item-specific compliance claims (e.g., meets USP/EP specifications) are Not specified for this item; refer to CoA/Spec Sheet.

Physical Properties

Item-specific physico-chemical specifications are not provided for this product. Refer to the CoA/Spec Sheet and product label for authoritative values.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet. (Dehydrated PCA is typically a free-flowing tan/beige powder; literature.)
• Solubility: Designed to be dispersed in water; components dissolve or suspend upon heating and boiling; agar melts at elevated temperature to form a sol once heated and gels upon cooling (literature).
• pH (prepared medium): Not specified for this item; refer to CoA/Spec Sheet. (Typical PCA pH after sterilization: ~7.0 ± 0.2 at 25 °C; literature.)
• Gelation: Agar gels on cooling, with gel point commonly in the 35–40 °C range and melting point typically 85–95 °C (literature, depends on agar grade and concentration).
• Density, refractive index, logP, BP/MP: Not applicable/meaningful for a complex hydrated gel system; not specified for this item.

Practical handling characteristics (general):

• The dehydrated medium readily wets and disperses with vigorous stirring; localized clumping can occur if added too quickly—sprinkle gradually into heated water while stirring (literature practice).
• Prepared plates yield a firm, clear-to-slightly opalescent gel suitable for colony counting; clarity depends on composition and sterilization conditions (literature).

Quality & Grades

• Grade: BioReagent (as provided). This generally denotes suitability for biological research workflows, including microbiology culture preparation, with attention to lot-to-lot consistency and performance metrics relevant to growth.

What BioReagent implies (general):

• Raw material selection and blending practices intended to minimize inhibitory contaminants that can suppress microbial growth or distort colony counts.
• Typical quality controls for PCA include sterility testing, pH of prepared medium, gel strength/clarity, and growth promotion testing (e.g., recovery of representative aerobic heterotrophs). Specific acceptance criteria are medium- and supplier-dependent.

Item-specific specifications such as pH target, gel strength, component assay, moisture content, plating recovery, or inhibitory substance limits are Not specified for this item; refer to CoA/Spec Sheet.

Best practices:

• Verify lot performance with in-house positive controls relevant to your method (e.g., ISO 4833, FDA BAM, or pharmacopeial enumeration methods) before critical work.
• Record lot numbers on each batch of plates for traceability and QA documentation.

Reaction & Applications

Chemical reaction applications are not applicable. Instead, this medium is used for microbiological enumeration.

Core applications (general/literature):

• Enumeration of aerobic mesophilic bacteria in foods, dairy, environmental samples, and cosmetics via plate count methods (e.g., pour plate or spread plate).
• Routine quality control testing and hygienic monitoring along production lines and in laboratories.
• Recovery and counting of heterotrophic bacteria in waters (when permitted by the method; some methods prefer R2A for potable water).

Methodological notes:

• Sample preparation typically includes serial decimal dilutions in appropriate diluents (e.g., peptone water, buffered saline) to achieve 25–250 CFU/plate.
• Pour plate vs spread plate: Many PCA methods use pour plates, mixing sample with molten medium (~45–50 °C) to capture both surface and subsurface colonies. Spread plating on pre-solidified PCA is also common for low-bioburden samples.
• Incubation (literature examples): Food matrices often incubate at 30 ± 1 °C for 48–72 h (e.g., ISO 4833 series) or at 35 ± 2 °C for ~48 h in North American practices. Always follow the governing method.

Performance considerations:

• Overheating (>100 °C for extended periods) can caramelize carbohydrates and reduce recovery. Minimize holding time at high temperature and pour promptly after sterilization and cooling to 45–50 °C.

Reaction Conditions

Classical reaction conditions do not apply. For practical laboratory use, the relevant “conditions” are preparation and incubation parameters for microbiological enumeration. Values below are general literature guidance and must be adapted to your method.

Preparation (general):

• Mass per liter: Not specified for this item; refer to label/CoA. (Many PCA formulations are prepared at ~23–25 g/L; literature.)
• Dissolve in purified water with heat and agitation. Boil gently to completely melt agar.
• Sterilize by autoclaving at 121 °C for 15 minutes (liquid cycle). Avoid excessive autoclave dwell to prevent medium degradation.
• Cool to 45–50 °C for pour plating; avoid temperatures above ~55 °C when mixing with samples to protect heat-sensitive organisms (literature).

Incubation (examples from literature/standards):

• Food matrices (ISO 4833 series): 30 ± 1 °C for 48–72 h.
• North American practices: 35 ± 2 °C for ~48 h for aerobic plate count in some methods.
• Water testing may use different media/conditions; follow method-specific guidance.

Quality checks:

• Verify pH of prepared medium (Not specified for this item; typical PCA ~7.0 at 25 °C; literature) and perform growth promotion/sterility tests before routine use.

Safety & Handling

Hazard classification specifics are not provided for this listing. Always consult the product’s SDS for authoritative safety data.

• GHS Signal word, H-statements, pictograms: Not specified for this item; refer to SDS.
• Primary hazards (general for dehydrated media): Low acute toxicity; dust may cause mechanical eye irritation or transient respiratory discomfort. Avoid inhalation of dust and contact with eyes. Some users may experience skin dryness or irritation upon prolonged contact (literature/general guidance).
• PPE: Laboratory coat, safety glasses, and appropriate gloves. Use a dust mask/respirator if airborne dusts are generated. Handle hot liquids and autoclaved media with heat-resistant gloves and eye/face protection.
• Incompatibilities: Avoid contact with strong oxidizers. Dehydrated media should be kept dry—moisture uptake can degrade performance. No known peroxide-formation hazard (general).
• First aid (overview, defer to SDS): Eye contact—rinse cautiously with water for several minutes; remove contact lenses if present and easy to do. Inhalation—move to fresh air. Skin contact—wash with soap and water. Ingestion—rinse mouth and seek medical advice if symptoms persist.
• Thermal hazards: Prepared medium is handled near boiling and immediately after autoclaving (121 °C). Prevent burns and pressure buildup; do not tightly cap flasks during autoclaving; vent appropriately (good lab practice).

Solvent Selection

This product is a dehydrated culture medium intended to be reconstituted with purified water; typical solvent selection considerations for small-molecule chemistry do not apply.

• Reconstitution medium: Use high-purity water (e.g., ASTM Type 1/2, or as required by your method). Avoid high ionic strength or buffered waters unless specified by your method, as these can alter gel behavior or colony recovery (general guidance).
• Miscibility/polarity: Not applicable; the powder disperses in water and forms a hydrogel upon heating and subsequent cooling due to agar.

Comparison with alternatives (general):

• PCA vs TSA (Tryptic Soy Agar): PCA is optimized for total aerobic plate counts/heterotrophic counts, whereas TSA is a richer, broader-spectrum medium. Choice depends on method requirements (e.g., ISO, USP, BAM) and matrix.
• PCA vs R2A: R2A favors recovery of stressed or oligotrophic bacteria from potable waters at lower nutrient levels; PCA is more nutrient-rich and often used for food and dairy enumeration.

Recommendation: Select the medium mandated by your regulatory/method framework; do not substitute without method validation.

Storage & Reconstitution

• Storage conditions (as provided): Room temperature. Keep container tightly closed, in a cool, dry place. Protect from moisture to prevent clumping and loss of performance.
• Shipping: Normal (as provided).
• Shelf life: Not specified for this item; refer to CoA/Spec Sheet.

Reconstitution and sterilization (general guidance):

• Use purified water. Add the manufacturer-recommended mass per liter. Not specified for this item; refer to label/CoA.
• Heat with stirring to dissolve; bring to a gentle boil. Sterilize by autoclaving at 121 °C for 15 min unless your validated method specifies otherwise.
• After autoclaving, cool to 45–50 °C before pouring plates or mixing with samples.

Prepared media/plates (general):

• Store poured plates in sealed sleeves or bags to minimize desiccation, typically at 2–8 °C, protected from light. Allow plates to equilibrate to room temperature and dry the surface before use.
• Avoid repeated melt/solidify cycles; prolonged holding of molten agar (>2–3 h at 50 °C) can reduce performance.

Research use note: For research use only (as provided). Always consult the product label and CoA/Spec Sheet for lot-specific instructions and performance parameters.

Structure & Identity

This product is a complex, dehydrated microbiological medium rather than a single defined molecule.

• Item: Plate Count Agar (PCA), SKU P1528375
• Type: Dehydrated culture medium for enumeration of aerobic heterotrophic bacteria
• Composition: Not specified for this item; refer to CoA/Spec Sheet. (Typical components in literature include tryptone/peptone, yeast extract, glucose/dextrose, and agar as gelling agent.)
• CAS, CID, InChIKey, SMILES: Not applicable to mixtures; not specified for this item.
• Molecular formula and molecular weight: Not applicable to mixtures; not specified for this item.

2D/structural description (general):

• PCA is a blended powder comprising peptides (from casein/soy digests), carbohydrates (often dextrose), mineral/trace components from yeast extract, and agar, a sulfated polysaccharide that forms a thermo-reversible gel upon cooling. There is no single discrete molecular structure; instead, it is a formulated mixture optimized for broad bacterial recovery and colony formation on solid surfaces.

Identity confirmation (general practices):

• Medium identity is typically verified by: appearance (homogeneous tan-to-beige powder; visual), pH of the prepared medium (literature: ~7.0 at 25 °C), gel strength/clarity after sterilization, and growth promotion testing (enumeration performance with control strains).

Synthetic Utility

Not applicable. Plate Count Agar is a formulated microbiological medium and is not employed as a reagent or building block in chemical synthesis. For synthetic chemistry, refer to individual chemicals (solvents, catalysts, monomers, building blocks) where reactivity and functional group transformations are relevant.

If your workflow combines microbiology with chemical analysis (e.g., extractables/leachables, metabolite profiling), prepare PCA plates using validated protocols to avoid confounding variables in downstream analytical assays.

Target Specificity

Not applicable. This product is not an antibody, probe, or targeted affinity reagent. PCA is a non-selective culture medium designed to support a broad range of aerobic heterotrophic bacteria for total count enumeration rather than species-specific detection.