Selecta Digital S Manual Colony Counter

Overview

The Selecta Digital S Manual Colony Counter is a precision-engineered, benchtop microbiological counting instrument designed for reliable, operator-controlled enumeration of viable microbial colonies on standard agar plates. Operating on the principle of visual identification and tactile actuation, it supports manual colony enumeration without image capture or algorithmic analysis—making it ideal for routine QC laboratories, teaching environments, and resource-constrained settings where simplicity, durability, and regulatory traceability are prioritized over automated image processing. Its dual-background illumination system enables optimal contrast differentiation across diverse colony morphologies (e.g., opaque, translucent, pigmented, or mucoid), while the ergonomically adjustable stand ensures consistent viewing geometry across users and shifts. As an imported instrument manufactured in Spain under ISO 9001-certified production protocols, the Digital S complies with fundamental design requirements outlined in ISO 4833-1:2013 (microbiology of food and animal feeding stuffs) and EU Annex I of Regulation (EC) No 2073/2005 for ready-to-eat foods.

Key Features

• Tactile pressure-activated counting interface with audible beep feedback and mechanical click confirmation—ensuring unambiguous registration of each colony count and minimizing transcription errors.
• 2× optical magnification lens with 12.5 cm clear aperture, mounted on a vertically adjustable support arm to accommodate varying plate thicknesses and user posture preferences.
• Switchable dual-illumination base: selectable transmitted white light (for transparent or semi-transparent colonies on dark media) and matte black non-reflective field (for high-contrast visualization of light-colored or faint colonies on nutrient-rich agars).
• Robust ABS housing with chemical-resistant surface finish; designed for repeated disinfection with 70% ethanol or quaternary ammonium solutions per CLSI M22-A3 guidelines.
• Zero-software dependency architecture—no operating system, no drivers, no firmware updates—eliminating cybersecurity vulnerabilities and ensuring uninterrupted operation during GLP/GMP audits.

Sample Compatibility & Compliance

The Digital S accommodates all standard circular Petri dishes ranging from 50 mm to 120 mm in diameter, including polystyrene, polypropylene, and glass variants. Its open-platform design permits direct placement of stacked plates (up to two layers) without removal from incubation packaging—reducing contamination risk during transfer. The device meets mechanical safety requirements per IEC 61010-1:2010 (Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use) and carries CE marking for conformity with EU Directive 2014/30/EU (EMC) and 2014/35/EU (LVD). While not a Class I medical device, its counting methodology aligns with USP and Ph. Eur. 2.6.12 for aerobic microbial enumeration when used within validated laboratory procedures.

Software & Data Management

This is a standalone hardware-only colony counter with no embedded microprocessor, memory storage, or digital connectivity. All counts are recorded externally—either manually in bound laboratory notebooks or within LIMS-integrated spreadsheets. The absence of electronic data storage eliminates requirements for FDA 21 CFR Part 11 compliance, audit trails, or electronic signature validation—making it suitable for laboratories maintaining paper-based quality systems under ISO/IEC 17025:2017 Clause 7.5.1. Calibration verification is performed using NIST-traceable grid test slides (e.g., Bio-Rad Colony Count Standard Slide), with documented checks conducted prior to each analytical batch per internal SOPs.

Applications

• Routine enumeration of total viable counts (TVC) in pharmaceutical water systems (PW, WFI) per USP .
• Environmental monitoring (EM) of cleanroom surfaces and air samplers in sterile manufacturing facilities.
• Microbial limit testing (MLT) of non-sterile drug products per USP and EP 2.6.12.
• Food safety testing for mesophilic aerobes, yeasts, molds, and coliforms in raw materials and finished products.
• Academic microbiology instruction—supporting hands-on training in aseptic technique, isolation streaking, and colony morphology interpretation.

FAQ

Is the Digital S compatible with spiral platers or membrane filtration setups?
Yes—it accepts standard 50–120 mm membranes placed directly on the counting stage, and spiral-plated agar plates up to 100 mm in diameter.
Does it require calibration certification or annual servicing?
No formal calibration is required; however, daily operational verification using a reference grid slide is recommended per ISO 11133:2014 Annex D.
Can the unit be decontaminated with autoclave steam or hydrogen peroxide vapor?
No—only surface wipe disinfection with alcohol-based or low-level hospital-grade disinfectants is permitted. Do not immerse or expose to saturated steam.
Is the audible beep volume adjustable?
No—the fixed-frequency 2.8 kHz tone is optimized for audibility in typical laboratory ambient noise levels (≤65 dB(A)).
What power source does it use?
It operates via a universal 100–240 V AC, 50/60 Hz input with integrated switching power supply; no batteries or external adapters are needed.