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Ice Point and Boiling Point Methods Microbica Laboratory Partners, inc. © 2011 1 www.microbica.com.

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Presentation on theme: "Ice Point and Boiling Point Methods Microbica Laboratory Partners, inc. © 2011 1 www.microbica.com."— Presentation transcript:

1 Ice Point and Boiling Point Methods Microbica Laboratory Partners, inc. ©

2 Why calibrate a thermometer? Directives or standards such as ISO 9000 or ISO require organizations to provide accurate temperature measurements traceable to national or international standards. It is an important part of quality assurance in industry - for example in manufacturing to guarantee the quality of a product- and also to ensure effective testing or calibration by laboratories. Temperature is a critical measurement for ensuring the safety and quality of many food products. Whether monitoring temperatures at receiving, throughout production or final product storage and distribution, thermometer calibration is essential. The validation, verification reassessment section of the Hazard Analysis and Critical Control Point system stated in the Code of Federal Regulations (9CFR 3:417.4) specifies that instruments used for monitoring critical control points must be calibrated. Choosing a thermometer: If your thermometer is not accurate within +/- 2°F of 32°F., adjust the thermometer accordingly. The ice point method permits calibration to within 0.1°F. If your thermometer is not accurate within +/- 2°F of 212°F., adjust thermometer accordingly. The boiling point method permits calibration to within 1.0°F. Next Page Microbica Laboratory Partners, inc. ©

3 Use an insulated Cup for thermal stability We recommend a thermos over Styrofoam cups Measure the cup height against your thermometer probe Probe should be at least one inch shorter than the cup Place hole in center of thermos lid. Microbica Laboratory Partners, inc. (c)

4 Add ½ crushed ice and ½ tap water (distilled preferred) Allow to set for couple minutes Place Thermometer probe in center hole Slosh Ice-water to verify stability. Readings 32 o F +/- 2 o F =Ok 32 o F = 0 o C Prefer 32 o F +/- 0.1 o F Microbica Laboratory Partners, inc. (c) If the temperature is not at 32 o F (0 o C), then hold the calibration nut securely with a wrench and rotate the head of the thermometer until it reads 32ºF (0 o C). Follow manufactures instructions.

5 Use a Pyrex cup or flask. Metal pot not preferred Fill cup 1.5inch below top. Bring water to a slow boil. Then place Probe in center of cup for 1-2minutes or until stable. Keep probe off bottom of cup Use a non-metal support ( safety ) with vents/slots ( keeps steam off dial ) for visibility. And prevents loss of probe in hot liquid. Example: pasta scoop. Microbica Laboratory Partners, inc. (c) Water boils at 212 o F (100 o C) at elevations of sea level to 1,000ft.

6 Bimetallic Dial thermometers are sensitive only to about 2inches from the tip. Most have a dimple indicator. Microbica Laboratory Partners, inc. © The full bimetallic part of this sensor must be immersed in the liquid (soup) or solid (meat) for accurate readings. Test slim cuts or portions from the side for best results. Cut away view

7 Dial: If the temperature is not at 32 o F (0 o C), Ice Point or 212 o F (100 o C) Boiling Point, then hold the calibration nut securely with a wrench and rotate the head of the thermometer. Microbica Laboratory Partners, inc. (c) Digital: Follow manufactures instructions.

8 Microbica Laboratory Partners, inc. (c) Laboratory Calibration Boiling Flask, glass thermometer supported by clamp and stand Correct. Note: Thermometer centered and does not touch bottom

9 Microbica Laboratory Partners, inc. (c) Boiling Point Calibration Boiling Metal Pot, with clipped thermometers. Not Preferred. Do not cook thermometers during calibration. Does tip contact the pot or extend away? Metal Pot and water not necessarily same temperatures

10 Microbica Laboratory Partners, inc. (c) Boiling Point Calibration Boiling Metal Pot, With metal tongs. Not Preferred. Note: Cooking method not good for calibration. Salad tongs not made to hold thin rods. Thermometer can slip out.

11 Microbica Laboratory Partners, inc. (c) Ice Point Calibration Covered insulated cup, glass thermometer with clamp and stand. Acceptable Technique Avoid Styrofoam when possible Never use glass thermometers with food.

12 Microbica Laboratory Partners, inc. (c) Ice Point Calibration Cubed Ice in water glass Not Preferred. Use crushed ice and insulated cup

13 Microbica Laboratory Partners, inc. (c) Ice Point Calibration Glass thermometer in ice NEVER USE GLASS THERMOMETERS IN FOOD !!!

14 Microbica Laboratory Partners, inc. (c) CALIBRATION SUMMARY Avoid Styrofoam cups. Save environment Pyrex cups work well for both Ice Point and Boiling Point Insulated Cups with plastic lids best for Ice Point Calibration Contact us atwww.microbica.com

15 Microbica Laboratory Partners, inc. ©


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