Hanna Instruments HI98501 Precision Digital Thermometer

Overview

The Hanna Instruments HI98501 is a high-accuracy, handheld digital thermometer engineered for rigorous temperature monitoring across food safety, laboratory, and field applications. Utilizing a precision Pt1000 RTD (Resistance Temperature Detector) sensor embedded in a stainless-steel needle probe, the instrument operates on the fundamental principle of resistance-based thermal measurement—where temperature-induced changes in electrical resistance are linearly converted to calibrated Celsius readings. Designed specifically to meet HACCP (Hazard Analysis Critical Control Point) compliance requirements, the HI98501 delivers traceable, repeatable measurements from –50 °C to +150 °C with an accuracy of ±0.3 °C within its central range (0 °C to +100 °C). Its robust mechanical architecture eliminates the fragility and limited range inherent in traditional mercury or alcohol glass thermometers, while its compact form factor and intuitive interface support rapid deployment in both controlled lab environments and dynamic production-floor settings.

Key Features

• Stainless-steel needle probe (Ø1.5 mm × 100 mm) optimized for penetration into semi-solids, viscous liquids, air streams, and gaseous media
• Manual calibration capability via internal offset adjustment (±0.3 °C range), accessible through a dedicated switch under the battery compartment
• Large backlit LCD display with 0.1 °C resolution and <2.5-second response time (t₉₀) in water at 25 °C
• Auto-power-off function after 8 minutes of inactivity to extend battery life (2 × AAA alkaline cells)
• IP67-rated housing for dust and temporary immersion resistance (up to 1 m for 30 min)
• Self-diagnostics at power-on: displays real-time sensor integrity status and calibration flag on startup

Sample Compatibility & Compliance

The HI98501 is validated for direct contact measurement in heterogeneous matrices including raw and processed meats, dairy products (e.g., milk, cheese curd, yogurt), bakery doughs, sauces, and ambient air/gas streams. Its probe geometry minimizes thermal mass interference and ensures minimal sample disturbance during insertion. The device conforms to ASTM E74–22 (Standard Practice for Calibration of Thermometers) and supports GLP-compliant documentation when used with external logging accessories. While not intrinsically rated for hazardous locations, it meets IEC 61000-4 electromagnetic immunity standards and is routinely deployed in USDA-inspected facilities where FDA 21 CFR Part 11 data integrity is maintained through manual recording protocols.

Software & Data Management

The HI98501 operates as a standalone instrument without proprietary software dependencies. All calibration and operational parameters are stored in non-volatile memory. For traceability, users may manually log timestamps, measured values, and operator IDs alongside environmental notes in paper-based or LIMS-integrated electronic records. When paired with optional Hanna HI92000 Data Logging Software (via RS232 adapter), the unit supports export of time-stamped measurement series in CSV format—including probe ID, date/time stamp, temperature value, and calibration offset status—for audit-ready reporting aligned with ISO/IEC 17025 clause 7.7 (Uncertainty of Measurement) and HACCP Principle 4 (Monitoring Procedures).

Applications

• HACCP-critical checkpoints: cold chain verification (chillers, blast freezers), cooking endpoint validation (meat core temp ≥71 °C), and holding temperature compliance (≥60 °C for hot-held foods)
• Quality control in dairy processing: pasteurization temperature profiling, fermentation monitoring, and storage tank audits
• Research and development labs: thermal stability testing of emulsions, gels, and hydrocolloid systems
• Environmental health inspections: surface temperature mapping of food contact surfaces and refrigerated transport units
• Veterinary field use: rectal and intramuscular temperature assessment in livestock with minimal tissue trauma

FAQ

Does the HI98501 require periodic factory recalibration?
No—its manual offset adjustment function enables user-performed verification and correction against NIST-traceable reference standards (e.g., dry-block calibrators or ice-point baths) at defined intervals per internal QA procedures.
Can the probe be sterilized in an autoclave?
No—the HI98501 probe is not autoclavable; however, it withstands repeated cleaning with 70% ethanol, quaternary ammonium compounds, or sodium hypochlorite solutions per FDA Food Code Annex 2 guidelines.
Is the HI98501 compliant with EU CE marking requirements?
Yes—it bears CE marking under the Low Voltage Directive (2014/35/EU) and EMC Directive (2014/30/EU), with conformity assessed by TÜV Rheinland (Certificate No. R 50362052 0001).
What is the typical battery life under standard usage?
Approximately 200 hours of continuous operation or 12 months in standby mode with auto-off enabled.
How does the HI98501 compare to thermocouple-based handheld meters?
Unlike Type-K thermocouples, the Pt1000 RTD sensor provides superior long-term stability (<0.1 °C drift/year), tighter linearity over wide ranges, and immunity to cold-junction compensation errors—critical for regulatory audit readiness.