HKM MFS-3-PRO Intelligent Microbial Limit Tester

Overview

The HKM MFS-3-PRO Intelligent Microbial Limit Tester is a dedicated vacuum-assisted membrane filtration system engineered for quantitative microbial enumeration in regulated pharmaceutical, biotechnology, food, cosmetic, and public health laboratories. It operates on the principle of standardized membrane filtration—where liquid samples are drawn under controlled negative pressure through sterile, low-protein-binding filter membranes (typically 0.45 µm or 0.22 µm pore size), retaining viable microorganisms on the membrane surface. The captured microorganisms are then transferred aseptically onto appropriate solid culture media (e.g., Soybean–Casein Digest Agar or Tryptic Soy Agar), incubated, and enumerated via colony-forming unit (CFU) counting. This method aligns with pharmacopoeial requirements—including the Chinese Pharmacopoeia (ChP) 2020 General Chapter Microbial Limits Tests—and supports both total aerobic microbial count (TAMC) and total combined yeasts and molds count (TYMC) determinations.

Key Features

• Triple-channel independent vacuum control: Three detachable pump heads operate simultaneously yet independently, each with programmable run time and automatic termination—enabling parallel processing of diverse sample types or replicates without cross-contamination risk.
• Integrated high-vacuum silent diaphragm pump: Eliminates need for external buffer flasks or oil-lubricated vacuum sources; enables direct waste liquid discharge into laboratory drainage systems, minimizing benchtop footprint and maintenance overhead.
• Full audit trail capability: All operational parameters—including date/time stamp, operator ID, channel selection, filtration duration, and membrane type—are logged automatically. Stores up to 6,400 complete sampling records internally with non-volatile memory retention.
• Multi-tiered access control: Four distinct user roles (Super Administrator, Administrator, Engineer, Operator) enforce role-based permissions for method editing, calibration, data export, and routine operation—supporting GLP/GMP-aligned workflow governance.
• Autoclavable stainless-steel hardware: Filter cups and cup holders are constructed from 316L stainless steel, validated for repeated sterilization at 121 °C/15 min (wet heat) or dry heat up to 180 °C—ensuring compatibility with aseptic processing environments.
• Flexible consumables support: Accommodates standard 47 mm or 50 mm diameter filters—including mixed cellulose ester (MCE), polyethersulfone (PES), and nylon membranes—as well as disposable polycarbonate or reusable stainless-steel filter assemblies.
• Built-in thermal label printer: Generates tamper-evident, time-stamped labels directly linked to each filtration event—facilitating sample tracking, chain-of-custody documentation, and regulatory inspection readiness.

Sample Compatibility & Compliance

The MFS-3-PRO is validated for use with purified water, water for injection (WFI), pharmaceutical raw materials, final drug products, cosmetics, beverages, environmental swab rinsates, and air sampling impinger fluids. Its design conforms to national and pharmacopoeial standards including GB 8538–2016 (Natural Mineral Water Testing), GB/T 5750.12–2006 (Drinking Water Microbiological Methods), GB/T 18204.5–2013 (Legionella Detection in Public Places), GB/T 19298–2014 (Packaged Drinking Water), and ChP 2020 . While not FDA 510(k)-cleared or CE-marked per IVD Directive, its architecture supports alignment with ISO 17025 quality management systems and provides foundational functionality required for 21 CFR Part 11-compliant data integrity when deployed with validated IT infrastructure and procedural controls.

Software & Data Management

The instrument features an embedded Linux-based operating system with dual-language (English/Chinese) GUI displayed on a 7-inch HD capacitive touchscreen. No external PC is required for basic operation; however, optional USB data export enables transfer of CSV-formatted logs to LIMS or ELN platforms. All stored records include immutable timestamps, operator credentials, and parameter configurations—fulfilling ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available). Password-protected firmware updates and configurable auto-logout intervals further reinforce data security and system integrity.

Applications

• Routine microbial monitoring of purified water and WFI distribution loops in pharmaceutical manufacturing facilities.
• Release testing of non-sterile dosage forms (e.g., tablets, capsules, ointments) per ChP and USP .
• Environmental monitoring program (EMP) support—including isolator, cleanroom, and HVAC system rinse samples.
• Microbial load assessment of raw materials, excipients, and packaging components prior to processing.
• Public health surveillance: Legionella pneumophila detection in cooling tower water per GB/T 18204.5–2013.
• Food safety validation: Total viable count (TVC) and coliform screening in beverage and dairy production lines.

FAQ

Is the MFS-3-PRO compliant with USP and ?
The system implements the membrane filtration methodology specified in USP , but full compliance requires integration into a validated laboratory workflow—including qualified filters, calibrated timers, trained personnel, and documented SOPs.
Can stainless steel filter cups be used with aggressive solvents?
Yes—316L stainless steel construction provides resistance to alcohols, acetone, and dilute acids/bases; however, prolonged exposure to halogenated solvents or strong oxidizers is not recommended without prior compatibility verification.
Does the device support electronic signature functionality?
No native digital signature module is included; however, exported CSV logs may be imported into validated ELN/LIMS systems that provide electronic signature capabilities per 21 CFR Part 11.
What is the maximum allowable viscosity for filtered samples?
Optimal performance is achieved with aqueous solutions ≤10 cP; higher-viscosity samples (e.g., syrups, suspensions) require pre-dilution or centrifugal clarification to prevent membrane clogging and ensure reproducible recovery rates.
How often does the vacuum pump require maintenance?
Under normal use (≤4 hours/day), the diaphragm pump requires only periodic inspection of inlet filters every 6 months; no oil changes or seal replacements are needed due to its dry-running, maintenance-free design.