Instrumentation & Calibration Flashcards

How often should a pH meter be calibrated in a sensory prep lab that uses it daily?

Answer: At least daily, with fresh buffers that bracket the expected range

Daily multi-point calibration with fresh buffers that bracket the sample range keeps pH readings accurate.

A two-point pH calibration for acidic beverages would typically use which buffers?

Answer: pH 4.00 and pH 7.00

Buffers at pH 4 and 7 bracket the acidic range common in beverages.

Serving temperature for samples is checked with a thermometer. How is its accuracy best verified?

Answer: Against a NIST-traceable reference thermometer or an ice-point check

Thermometers are verified with an ice-point check (0 °C) or against a traceable reference thermometer.

Which statement best defines measurement traceability?

Answer: An unbroken chain of calibrations linking a result to national or international standards

Traceability means a documented calibration chain links the measurement to a recognized reference such as NIST.

An analytical balance used to weigh tastant solutes shows drift. What should be checked first?

Answer: Level, draft shielding, and calibration with certified weights

Balance accuracy depends on proper leveling, freedom from drafts and vibration, and calibration against certified masses.

Water activity (aw) meters are verified using which type of standard?

Answer: Saturated salt solutions or certified aw standards

Saturated salt solutions and certified standards produce known equilibrium relative humidity for checking aw meters.

What is the main purpose of keeping a calibration log for each lab instrument?

Answer: To document calibration history and show measurement reliability

Calibration logs give auditable proof that instruments were in tolerance when data were collected.