Food Safety Lesson 11

8/8/2019 Food Safety Lesson 11

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Manufacture of Ground Beef

Class periods: one to two 30-min. class periods

Supplement Section: Processing and Manufacturing PA PAS for FCS: 9.3.3 A, 9.3.3 B,9.3.6 B, 9.3.9 B, 9.3.12 B.

National Education Standards: FCS 8.2.1, 8.2.3, 8.2.4, 8.2.5, 8.2.6, 9.2.1, 9.2.3, 9.2.4,9.2.5, 9.2.6; LA 2, 3, 035, 132, 278; SC 5.

Processing and Manufacturing Lesson 11

LESSON SUMMARYStudents will learn how ground beef is madeand what is done to keep it safe.

Objectives

Students will:

Show the proper temperature to cookground beef.

Recognize the critical control pointsduring the processing of ground beef.

Materials Provided

Worksheet:

1. Evaluation of Ground Beef Topping forPizza

Teacher Information Sheets:

1. What Team Members Should Do

2. Glossary of Bolded Terms

Resources:

A-1 and A-2, two excerpts from novel The

Jungle by Upton Sinclair Interventions to Control Pathogenic Micro-

organisms at the Meat Processing Plant

HACCP for Hamburgers... from Farm toTable

Newspaper articles about hamburgerrecall for E. coli at the Jack In The Box fastfood restaurant in Seattle, Washington

Which Hamburger Is Safe? O. PeterSnyder, Jr., Ph.D. Hospitality Institute ofTechnology and Management

What Every Consumer Needs to KnowAbout Food Thermometers. O. Peter

Snyder, Jr., Ph.D. Hospitality Institute ofTechnology and Management

FSIS Food Safety: Thermy, Use a FoodThermometer.

Suggested Presentation Aids

Raw ground beef, bulk form, and groundbeef patty

Equipment used to cook ground beef:skillet, wooden spoon, can to drain grease

Fresh or frozen plain pizza, uncooked,ready to add ground beef topping

Oven to cook pizza, serving utensils,plates, napkins, forks and knives

Foil, plastic resealable bag, or plasticcontainer to properly store pizza

Sponsored by USDA

This material is based upon work supported by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Agreement No.99-41563-0722by J. Lynne Brown, Melanie Cramer, and Kristine Barlow,College of Agricultural Sciences, The Pennsylvania State University.


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Processing and Manufacturing: Lesson 11 Manufacture of Ground Beef 2


LESSON PLAN

Class Period 1

Introduction

Wow, that pizza looks delicious. Chances are

you arent thinking about anything but eatingthe hot, tasty pizza. But wait! The groundbeef has gone through a number of changesbefore being added to the pizza as a topping.There are several steps in the process ofconverting the live animal into ground beefthat affects the safety of the meat you eat.

Lesson Sequence

Conduct a poll of how many students likehamburger meat or hamburgers. Of thosewho do, how many prefer it rare, mediumrare, medium, medium well, or well done?Write the results on the board. What haveyou heard in the news about eating ham-burgers cooked to rare or medium in tem-perature? Record on the board what theyhave heard.

Ground beef must be cooked to a temper-ature of 160 F to kill any pathogen thatmay be present.

During the many stages of slaughter, pro-cessing of ground beef, shipping, packag-ing, distribution, storage, final preparationof hamburger in the grocery store, and con-sumer purchase, storage, and preparation,ground beef is exposed to many differenttypes of microorganisms and bacteria.

Pathogens can be controlled at eachstage using the HACCP plan (Teacherinformation sheet 1). HACCP will bediscussed later in the lesson.

Food safety has been a concern in theUnited States since the late 1800s whensoldiers in Cuba during the Spanish-

American War died from eating taintedmeat sent by American meat packers.

In 1906 Upton Sinclair wrote the novel TheJungle, which exposed the filthy conditionsand unsafe production methods of themeat packing industry.

During that same year, 1906, PresidentRoosevelt passed the Pure Food and Drug

Act and the Meat Inspection Act to elimi-nate the atrocious conditions in the meatpacking plant.

Closure class period 1

Pass out and read together the excerptfrom The Jungle by Upton Sinclair.

Discuss the reactions of the students.

Class Period 2

Refer to the Food Safety Team memberlesson. Read the Government responsibi-lities as a member of the Food Safety Team,Teacher information sheet 2. (If this is astand-alone lesson, some introduction ofthe Food Safety Team may need to bedone.)

Do these agencies ensure a safe foodsupply?

Pass out the articles about the meattainted with E. coli 0157:H7 bought at theJack In The Box fast food restaurant.Four children died from kidney failure and55 adults died from kidney disease.Discuss students reactions to the articles.

How could this happen if we have a foodsafety team comprised of three or moreagencies that are enforcing regulationsand conducting plan inspections? (Onlyvisual inspections are done.) Many of theproblems with the food safety system aredue to the fragmented jurisdictions andresponsibilities of the major players on theFood Safety Team. Do newspaper articleson food recalls change your viewpointsabout what you eat?

Can federal agencies inspect every pro-duct that comes off of every manufac-turing line? Companies inspect randomsamples for quality control. Between 1906and 1993, the meat inspection systemwas based on what Food Safety andInspection Service inspectors could see:evidences of animal diseases, defects,


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and visible contamination of meat.Dangers to consumers are often fromunseen bacteria.

All meat and poultry plants must incorpo-rate a system known as Hazard Analysisand Critical Control Points, orHACCP.

All plants must implement standard opera-ting procedures to ensure cleanliness offacilities and equipment, as well asemployee hygienic practices.

HACCP identifies hazards, develops aplan to prevent or control such hazards atcritical control points, records what isdone at each of these points, and verifiesthat the system is working on an ongoingbasis. This is done by testing, constantmonitoring, and reviewing records.

Closure class period 2

Cut out articles from the newspaper orfind articles in the library about the meatprocessing industry. What issues are pre-sented in these articles? List the positiveand negative issues in the articles. WasHACCPmentioned in the article?

Suggested Learning Activities

Have students read the article HACCPforHamburgers from Farm to Table aboutthe production of hamburger from the farmto the table and about proposed changesfor safer meat. Students will identify thesteps involved to ensure food safety forhamburger and where problems mayoccur that may result in illness or some-times death from food poisoning.

Teacher will demonstrate the cooking ofground beef to be placed on the pizza. As

the ground beef is cooking, the teacherwill point out the safety points to remem-ber for cooking beef.

Safety steps when cooking ground beef:Clean all utensils and equipment with hot,soapy water before and after cookingground beef, cook ground beef until inter-nal temperature is 160 F, and use a cleanplate to hold the cooked meat (do not use

the same plate used for raw meat). Have astudent take the internal temperature ofthe ground beef with a thermistor thermo-meter. Read the articles on thermometersat the end of this lesson.

After ground beef is cooked, add to the

pizza and bake at required temperature. Students will evaluate the handling, cook-ing, and serving process for the groundbeef. Were the proper steps taken to en-sure the safety of the ground beef duringthe handling, cooking, and servingprocess?

Have students properly store the leftoverpizza to ensure limited bacteria contami-nation. Wrap in foil or place in a sealedplastic container, and place in refrigerator

to be eaten within two days, or place infreezer for up to two weeks.

Evaluation

Evaluation of handling, cooking, and ser-ving of ground beef as a topping for thepizza (Worksheet 1). Outline the criticalcontrol points for cooking ground beef.

Quiz #11.

Examination #3 at the end of the

Processing and Manufacturing unit.

References

The Pennsylvania State University, Dairyand Animal Science Web site: http://www.das.psu.edu

Guidelines for cooking ground beef Website: http://www.beef.org/kitchen/recipes/grnd-bf-guide.htm and www.beef.org/kitchen/safety/index.htm

Bacterial Contamination of Food, Collegeof Agricultural Sciences, CooperativeExtension. Produced by J. Lynne Brown,Ph.D., R.D., Associate Professor. Lesson9, Inspecting the Fast Food Restaurant.Newspaper articles about hamburgerrecall for E. coli at the Jack In The Box fastfood restaurant in Seattle, Washington.


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A-1 and A-2, excerpts from The Jungle, byUpton Sinclair.

SLIC, Secondary Level InterdisciplinaryCurriculum, produced by Star Campbell,MS, M. Ed., RD and Kay Meyers, Ph.D.Pennsylvania Department of Education.

Division of Food and Nutrition, 333 MarketStreet, 4th Floor, Harrisburg, PA 17126-0333.

HACCP for Hamburgers... from Farm toTable. HACCP, USDA, Food Safety andInspection, July 1997. Written by BruceKaplan, Anne McGuigan, and Cici Williamson.SLIC, Secondary Level InterdisciplinaryCurriculum, PA Department of Education,1997. Developed by Star Campbell, MS,M. Ed., RD and Kay Meyers, Ph.D.

Pennsylvania Department of Education,Division of Food and Nutrition, 333 MarketStreet, 4th Floor, Harrisburg, PA 17126-0333. Biology and Microbiology section,lesson: Hamburger Sizzler: BacterialPopulation Counts, B-2.

Which Hamburger Is Safe? and Bi-metallic Coil Thermometer: Unsatisfactoryfor Measuring Food Temperatures, http://www.hi-tm.com/Documents/Bimet-pic.html, and What Every Consumer

Needs to Know About Food Thermometers,http://www.hitm.com/Documents/Thermoms.html, by O. Peter Snyder, Jr.,Ph. D. Hospitality Institute of Technologyand Management, St. Paul, MN.

Thermy Web site: http://www.fsis.usda.gov/thermy/index.htm


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Worksheet 1

Evaluation of Ground Beef Topping for Pizza

Score handling, cooking, serving, and storing of ground beef topping and pizza using

the rating scale of 1-4. Four is the highest score and one is the lowest score. Makecomments and corrections in the box under the rating.

Criteria 4 3 2 1

Wash hands

Work area andequipment areclean

Keep raw and

cooked meatseparate, avoidcrosscontamination

Turn ground beefover and break uplarge pieces todistribute the heat

Cook ground beef

to 160F

Use clean plate tohold cooked meat

Serve food assoon as possibleafter cooking

Wrap leftoverground beef

topping or pizza instorage containeror wrapper

Store as soon aspossible inrefrigerator orfreezer

Name

Class/Period

Date


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Teacher information sheet 1

WHAT TEAM MEMBERS SHOULD DO

Government Agencies Farmers

Make food safety rules and regulations Apply chemicals according to strictrules when growing crops

Inspect food processing plants Give drugs in safe amounts toanimals to help keep them disease free

Inspect grocery stores and all places that Maintain a clean living environment forserve food animals

Set the amount of pesticides that can be used Raise animals for foodby farmers

Enforce food safety regulations Grow crops for food

Identify where potential contamination can occur Keep rodents, insects, and wild fowland strictly manage and monitor these points to away from the animals and their foodensure the process is controlled and to produce suppliesthe safest product

Clean equipment regularly, such asmilking machines or egg holders

Make sure workers follow safe hygiene

practicesProcessors Grocery and Retail

Prepare and package food Make sure cracked jars and bulgingcans are not sold

Keep factories clean Train personnel in safe food handling

Use food additives to preserve food Maintain foods at appropriatetemperatures; monitor frozen food andrefrigerator cases for consistenttemperatures

Maintain cleanliness when processing food Rotate stock regularly so foods aremoved off the shelf by their sell dates

Inspect raw materials and processing materials Clean and sterilize all surfaces that holdfood

Control temperatures throughout all stages of Put Safe Handling Instructions labels onprocessing packages


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Consumers Restaurant and Institutional

Buy and prepare food for family and friends Place sneeze covers over salad barsand dessert bars

Check the sell by freshness dates on food Make sure that all food sold is prepared

products before buying them under clean conditions

Refrigerate or freeze cold food immediately after Make sure that food servers wash theirpurchasing and/or preparing it hands before serving food and follow

general rules of sanitation

Wash fruits and vegetables before eating Make sure food is cooked toappropriate temperatures

Prepare foods on clean surfaces Workers who handle food do not handlemoney

Always wash hands before preparing food Dispose of garbage properly and keepdumpsites clean.

Cook foods thoroughly, check internal temperature Store food properly before use incooking

Store foods in small, shallow containers and Routinely scrub and sanitize counterrefrigerate quickly tops, equipment and floors

Separate: Dont contaminate

Adopted from Producer Through Consumer: Partners To a Safe Food SupplyPurdue University Cooperative Extension Service


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Teacher information sheet 2

Glossary of Bolded Terms

HACCP: Hazard Analysis and Critical Control Points. Identifies hazards, develops a plan toprevent or control such hazards at critical control points, records what is done at each of

these points, and verifies that the system is working on an ongoing basis.

Sticking: During slaughter a knife is stuck into the animals neck and the animal is bled out.

Evisceration: During slaughter the GI tract and organs are removed.

Bung removal: During slaughter, the tying and bagging of the animals bladder.

Lactic acid rinse: Spray washing the carcass with lactic acid to wash off any visible fecal ormicroscopic compounds to the carcass surface.


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A1


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A2


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have discussed this. However, three years ago, I was told that it would cost too much to

change the picture. As a result, if U.S. consumers use the type of thermometer as pictured,

they will most likely overcook their food. I hope that the USDA will consider showing a pic-

ture of a tip-sensitive thermometer on the labels of raw meat, fish, and poultry in the market

so that consumers will be able to accurately judge the doneness of these foods without

overcooking them.

The USDA still has a long way to go, because we do not need to cook to 160F. The refer-

ence it uses for 100,000-to-1 Salmonella kill also points out that 15 seconds at 155F or 52

seconds at 150F or 2.7 minutes at 145F will all give the same kill [Goodfellow, S.J. and

Brown, W.L. 1978. Fate of Salmonella inoculated into beef for cooking. J. Food Protect.

41(8):598-605]. Of course, the hamburger is even more red at these lower temperatures.

In summary, the USDA has made a small step forward in giving the public accurate informa-tion on cooking food. We have a lot more to do.

Other links:

Bimetallic coil thermometer: Unsatisfactory for measuring food temperatures:

http://www.hi-tm.com/Documents/Bimet-pic.html

What every consumer needs to know about food thermometers:

http://www.hi-tm.com/Documents/Thermoms.html

Bloody chicken:

http://www.hi-tm.com/Documents/Bloody-chik.html to HITM home page

Reprinted with permission from O. Peter Snyder, Jr., Ph. D.Hospitality Institute of Technology and Management, St. Paul, MN.

http://www.hi-tm.com/Documents/Bimet-pic.html,


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WHAT EVERY CONSUMER NEEDS TO KNOW

ABOUT FOOD THERMOMETERS

Copyright 1997

O. Peter Snyder, Jr., Ph.D.

Hospitality Institute of Technology and Management

St. Paul, Minnesota

DRAFT September 29, 1997

INTRODUCTION

This paper describes the general characteristics of thermometers that consumers and retail

food industry personnel commonly use to measure food temperatures. Each thermometer

has its own particular food use, as described. For each type of thermometer, the specific

food temperature range, time to respond, and other measuring characteristics are listed.

There is one characteristic that is common to all of these thermometers. There will be a

sensing zone at the tip, which can be the flat end of the temperature probe, a bulb that might

be 1/2 inch long, or a bimetallic coil that might be 2 1/2 inches long. In all cases, the tem-

perature-measuring zone must be inserted into the food at least 5 times, and preferably 10times, the diameter of the thermometer (probe). If it is not inserted far enough into the food,

the part of the thermometer probe that is not in the food could cool by heat loss up the stem

of the thermometer. This means that if a thermometer probe is 0.040 inch in diameter, it must

be inserted at least 0.2 inch into the food and preferably, 0.4 inch into the food. If the probe is

1/8 inch in diameter, which is quite common, the thermometer should be inserted 1 1/4

inches beyond the temperature-measuring zone in order to minimize the effects of the upper

part of the stem on the temperature-measuring zone. Depending on the measuring system,

the error can be quite significant. For example, in food such as a hamburger, where the tem-

perature might be 140F, if a thermometer with a 1/8-inch stem is inserted only 1/2 inch, there

could be a 20F variation in the temperature reading vs. the actual temperature because of the

cooling effects of the uninserted portion of the probe. The thermometer would read 120F for

this 140F hamburger. Please take into consideration the proper insertion of all of these ther-

mometers when evaluating which device is right for you.


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GLASS THERMOMETERS

Glass thermometers have been available for a long time. They are accurate and economical.

The most common products are filled with mercury and nitrogen gas above the mercury.

There are also products that use spirits instead of the mercury. This is less dangerous, be-

cause it is non-toxic in case of glass breakage. Some of the applications for these thermom-

eters include laboratories, dishwashers (used as a maximum registering), and fever thermom-

eters. The accuracy is typically 1 scale division. Calibration is accomplished by returning

the thermometer to a standards lab for verification against a NIST thermometer. Spirit-filled

types of glass thermometers are used as meat (+/-4% accuracy) and candy / deep-fry ther-

mometers (+/-10F accuracy) as well as other miscellaneous applications. There is no calibra-

tion. The temperature-sensing portion of the thermometer is the bulb at the end. It measures

the temperature of the volume surrounding the bulb. In a stirred liquid, it can be a very accu-

rate measurement. In a viscous food, one does not know if the hottest or coldest spot in the

food is actually measured.

MELTING-POINT INDICATOR, NON-REVERSIBLE TEMPERATURE MONITORS

Melting-point-type temperature monitor. A thin cardboard "stick" with a temperature-sensitive

melting dot. To be used after cooking food to see if a desired temperature has been reached.

(Trans World Services, Inc. is the only known current manufacturer.)

Food temperature measurement range and accuracy: type 1) 160F+/-1F; type 2) 142 to

144F+/-1F

Time to respond to food temperature: 5 seconds

Size: 2 1/2 inches long x 5/8 inch wide x 1/32 inch thick

Sensor: Irreversible, temperature-sensitive dot that melts and changes from white to black

Calibration: Preset

Use: When food is believed to be at 160F or 142 to 144F, depending on which type of unit is

used, push the specific cardboard temperature indicator into the food so that the dot is in the

middle (coldest spot) of the food. Wait 5 seconds. Pull out. If the food temperature is greater

than the melting point of the dot, the dot changes color. If not, continue to cook. The card-

board thermometer can be used a second time if it has not changed color in the same food

when the food has cooked a little longer.


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BIMETALLIC, METAL STEM, COIL THERMOMETERS

Metal sheath bimetallic coil meat thermometer. Used to monitor the temperature of meat

cooking in an oven by easy reading through the oven window.

Food temperature measurement range: 130 to 185F with 2F increments

Response time for a change from 75 to 150F when put in food: 30 seconds

Accuracy: +/-2F

Resolution: 2F

Dial diameter: 1 inch (or larger)

Stem lengths: 3 and 5 inches

Stem diameter: 0.250 inch

Sensor: Bimetallic coil

Length (wound): 1.2 inch + 0.750 inch plug length, to total approximately 2 inches.

Measurement zone: Will give an average temperature of the food around the thermometer

from the tip 2 inches up the stem.

Calibration: Factory set

Use: Put into a food, wait, and take a reading. However, it is difficult to know if the tempera-

ture of the spot or area of the food is the hottest / coldest part of the food. This is due to the

slow response of the unit. There is no time to do multiple probes of the food.

Metal sheath bimetallic coil candy / jelly / deep-fry thermometer. Used to monitor the tem-

perature of oil in deep fryers and also the endpoint cooking temperature of jellies and candy.

Food temperature measurement range: 200 to 400F with 5F increments


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Response time for a change from 75 to 350F when put in food: 2 minutes. (Some manufactur-

ers now claim that new, thinner-stemmed models a have much faster response time.)

Accuracy: +/-5F

Resolution: 5F

Dial diameter: 2 inches

Stem length: 5 inches



Length (wound): 0.83 inch + 0.47 inch plug length, to total approximately 1.3 inches.

Measurement zone: Will give an average temperature of the liquid from the tip 1.5 inches up

the stem.

Calibration: Factory set

Use: Put into the liquid, wait, and take a reading. The unit measures the temperature of theliquid surrounding the bimetallic coil. The liquid must be stirred to assure that the measure-

ment is accurate.

Pocket, 1-inch dial, plastic-faced, bimetallic coil thermometer with sheath and clip. Used for

many applications including food service and heating, ventilation, air conditioning, and refrig-

eration maintenance. Fits in a shirt pocket.

Food temperature measurement range: 0 to 220F with 2F increments (comes in other ranges)

Response time for a change from 75 to 150F in water: 25 seconds (some new models may be

faster)

Response time for a change from 75 to 35F in air: 1 minute 20 seconds

Accuracy: +/-2F


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Resolution: 2F

Dial diameter: 1 inch (or larger if desired)

Stem length: 5 inches



Length (wound): 1.250 inches (or longer) + clearance for the coil at both ends

Measurement zone: If there is a dimple about 2 inches up the stem from the tip, the minimum

submersion length is to the dimple. If there is no dimple, the minimum submersion length of

the stem is 3 inches. The measured temperature is the average between the hottest and

coldest spots of the food surrounding the sensing area from the tip to the dimple or 3 inches

up the stem.

Calibration: Should be checked for calibration each day and each time it is dropped. If it fogs

up inside the face, throw it away, because the hermetic seal is poor. Calibrate in a slush ice

bath. This is crushed ice with just enough water to come to the top of the ice. Do not use

boiling water; it is not accurate. Immerse the stem so that the thermometer measurement

zone is completely surrounded by slush ice. Wait 30 seconds. With a wrench, hold the nut onthe back of the dial. Twist the dial so that the needle points to 32F on the dial. Be accurate. If

the head of the thermometer is at all loose, throw it away. The thermometer will not stay cali-

brated. Check the thermometer in hot water to see that there is a reasonable reading. Some-

times, the bimetallic coil corrodes in the stem. It is assumed that if the thermometer is cali-

brated at 32F, it is accurate at 150F.

Use: Put into a food, wait, and take a reading of the average temperature of the food. It is

impossible to know if the temperature of the spot or area of the food is the hottest / coldest

part of the food, because the response time is so slow, and one does not have time to do

multiple probes.


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THERMISTOR THERMOMETERS

Pocket thermistor thermometer. Lightweight, small, 5 to 8 inches long x 1 inch wide x approxi-

mately 3/4 inch thick. Fits into a shirt pocket. Powered by a 1.5-volt replaceable photo-elec-

tronic battery with an average 1-year operating life.

Food temperature measurement range: -40 to 300F (500F in some models)

Response time for a change from 75 to 150F in water: approximately 12 seconds for a unit

with a 0.140-inch stem diameter

Response time for a change from 75 to 35F in air: approximately 1 minute 20 seconds

Accuracy: +/-2F from 32 to 212F

Resolution: 0.1F

Sensor: Ceramic bead resistor in the tip, potted in a high-thermal-conductivity epoxy.

Measurement zone: The tip must be immersed 0.5 inch into the food to compensate for ther-

mal conductivity down the stem to the tip. The measuring volume is the food, about 1/4 inch

diameter, around the tip.

Calibration: Inexpensive units usually cannot be recalibrated. These units can be checked in

slush ice to see if they either work or do not work. Some manufacturers are now offering more

expensive thermistor-type pocket thermometers that can be recalibrated. If used to measure

elevated temperatures such as hot oil, the sensor calibration can become inaccurate sooner.


ture of the spot or area of the food is the hottest / coldest part of the food, because the re-

sponse time is so slow, and one does not have time to do multiple probes.

Table thermistor thermometer. The meter is mounted in a small box that sits on a table. The

sensor is in a separate probe with a 3-to-4-foot cord. Depending on the cord material, the

probe can be put into food in an oven, and the meter can be used to measure the temperature

of food as it cooks. This unit is normally powered by a 9-volt battery. The operating character-

istics of the sensor are the same as the pocket thermistor thermometer.


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ture of the spot or area of the food is the hottest / coldest part of the food because of its slow

response. It is quite satisfactory for many measurements in a food market where food has

been at a temperature for a number of hours, and the mass has had time to come to a uni-

form temperature..

THERMOCOUPLE THERMOMETERS

Hand-held, pocket thermocouple thermometers are bigger than other food thermometers, at

least 3/4 inch x 2 1/2 inches x 5 inches. They are powered normally by a 9-volt transistor

battery with an operating life of 200 to 2,000 hours, depending on the electronics. (NOTE:

There are also table meters, 110-volt meters, and many different types of probes. The follow-

ing specification will only be for the hand-held, pocket thermocouple thermometer.)

METER

Temperature range: Industrial meters can range from -350 to 2,200F. Food meters normally

range from -40 to +400F. The best meter accuracy is perhaps +/-0.5F. Less expensive meters

can be +/-2F.

When the probe variation is added in, the accuracy can drop to +|/-1F or worse

Resolution: 0.1F or 1.0F, depending on selection

Meter update time: Approximately 2.5 times per second

PROBE

Probes can plug into / be attached to the meter directly or can be at the end of a separate 3-

to-4-foot plug-in cord. If the cord is made with a high-temperature covering, the probe can be

inserted into, and left in, food cooking in an oven. Probes are normally 4 to 5 inches long. The

critical part is the probe tip diameter. The smaller the diameter of the tip, the faster the re-

sponse. The thermocouple wires that measure temperature are usually welded at the tip ofthe probe in what is called a grounded junction. While rugged probes can be 0.125 inch in

diameter, for example, to measure frozen food, they are slow because of the mass of the tip.

The probe tip should be no larger than 0.062 (1/16) inch in diameter. The preferred probe tip

for response is 0.040 inch. Probe tips can be as small as 0.010 inch, but these are very deli-

cate.


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0.062-inch probe tip response time from 75 to 150F in water: 1.2 seconds

0.062-inch probe tip response time from 75 to 35F in air: 30 seconds

0.040-inch probe tip response time from 75 to 150F in water: 0.7 second

0.040-inch probe tip response time from 75 to 35F in air: 20 seconds

Use: This is the only thermometer capable of finding cold spots / hot spots in food. To mea-

sure the cold spots / hot spots, insert the probe directly into the food and push through the

food. A typical 4-ounce hamburger takes less than 3 seconds to measure. The meter reading

goes from hot, perhaps 175F, down to the cold center temperature, perhaps 145F, as the

probe tip is pushed through the food, and then immediately begins to rise as it goes out of

the cold center. It is possible to measure cold spot temperatures with an accuracy of +/-1F.

RTD THERMOMETERS

RTD thermometers can be very accurate, but the probes are big, and response is slow. Be-

cause of these limitations, they are not discussed. To obtain further information, contact the

author.

INFRARED THERMOMETERS

Hand-held, portable infrared thermometers measure the surface temperature of food andpackages of food without contact by measuring the intensity of the infrared ray emitted from

the surface. These thermometers are bigger than most traditional thermometers. They are

usually about 5 inches x 2 inches x 8 inches, although some units are slightly smaller. They

are normally powered by a 9-volt battery with a typical operating life of 20 to 50 hours. The

temperature range of IR thermometers can be from -50 to 5,400F (-46 to 3,000C). The IR

thermometers used in food applications normally range from -25 to 750F (-32 to 400C). The

accuracy of infrared thermometers varies from +/-0.5% of the reading, or +/- -1C (1.5F) to 2%

of the reading, or 2C (3F), whichever is greater. The resolution of infrared thermometers varies

from 1F or C to 0.1F or C, depending on the unit. The typical response time is from 1/4 sec-

ond to 1/2 second. In general, the more expensive infrared thermometers have better accu-

racy, resolution, and response times. Because IR thermometers only measure surface tem-

perature, they should only be used to survey the surface temperature of food products in

refrigerators, freezers, etc. They must be used with caution with hot food above 120F, be-

cause there is normally evaporative cooling at the surface of the food, and the surface can be


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10 to 30F colder than 1/4 inch below the surface. The reading is also very sensitive to the type

of surface. Metal surfaces emit energy much differently than food surfaces and printed plas-

tics. The normal IR monitor is typically set to measure a surface with an emissivity of 0.95,

which is appropriate for food and most food plastic films. They are very useful in food markets

where all refrigerated / frozen food can be checked in a few minutes. These units are very fast,

providing a reading in less than 1 second. Also, they do not waste any food, because there isno probe to penetrate the food. The one assumption made in these situations is that the

center and surface temperatures of the food are the same, which is typically true in food

markets, where the food has been in the cooler / freezer for a few hours. Applications in food

markets include: inspecting incoming products for proper shipping temperatures, checking for

proper storage temperatures in freezers and refrigerators, checking food held in warming

equipment, and checking the temperature of liquids and beverages. Because the surface

emissivity changes, one cannot accurately measure metal surfaces with simple IR thermom-

eters. Whenever one has doubt about the reading of the IR thermometer, one can check the

temperature with a micro-tipped thermocouple just below the surface of the food. In a restau-

rant, the IR has less application, because much of the food is unwrapped, and food tempera-

tures normally can be measured with a thermistor or thermocouple. To HITM home page

Reprinted with permission from O. Peter Snyder, Jr., Ph.D. Hospitality Institute of Technologyand Management, St. Paul, MN.http://www.hitm.com/Documents/Thermoms.html


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This publication is available in alternate media on request.The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personalcharacteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain anacademic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because ofage, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. Discrimination or harassment against faculty, staff, or students

will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University,201 Willard Building, University Park, PA 16802-2801; Tel 814-865-4700/V, 814-863-1150/TTY.


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http://www.fsis.usda.gov/thermy/index.htm

Thermy

http://www.fsis.usda.gov/thermy/index.htm


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BIMETALLIC COIL THERMOMETER:

UNSATISFACTORY FOR MEASURING FOOD TEMPERATURES

by O. Peter Snyder, Jr., Ph.D.

Hospitality Institute of Technology and Management

670 Transfer Road, Suite 21A

St. Paul, MN 55114

The bimetallic coil thermometer is not a satisfactory device for measuring food temperatures

for the following reasons as shown in the photographs.

1. The coil extends in the stem from about 1/4 inch to about 3 inches up the stem. This coil

measures the average temperature of the food surrounding the coil. In a pan of hot food, this

can be +/-50F, and the coil only gives the average temperature. For example, the food might

be 100F at the top of the pan and 200F at the bottom of the pan, and the coil reads 150F.


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2. The specification that the thermometer is accurate to +/-2F is only true under perfect

laboratory conditions. The thermometer must be perfectly calibrated in slush ice, not cube

ice, and the pointer must be precisely on 32F. The companies that make these thermometers

provide no guarantee of accuracy at 150F or higher, because the coil, after perhaps as little

as a week of use, can corrode in the stem, causing it to malfunction.

3. For many mechanical reasons, the stem can get filled with liquid from food or wash water

that seeps in around the gasket at the nut. This device is not designed to be immersed. The

Oregon Department of Agriculture has reported that when inspectors check thermometers in

operation, they are often off by more than 10F.

In summary, because of the problems with construction and calibration, this device cannot

be trusted to give an accurate reading. The thermistor or thermocouple should be used.

Reprinted with permission from O. Peter Snyder, Jr., Ph.D. Hospitality Institute of Technologyand Management, St. Paul, MN.http://www.hitm.com/Documents/Thermoms.html


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Quiz 11

Unit: Processing and Manufacturing

Lesson: Manufacture of Ground Beef

Matching: Match the vocabulary terms in column A with the definitions in column B.Write the letter of the definition in column B in the space next to the terms in column A.

A B

_____ 1. HACCP A. Wash any visible fecal or microscopic compounds to the carcasssurface.

_____ 2. Evisceration B. Very accurate instrument for reading temperature of cookedfood.

_____ 3. Thermistor C. Hazard Analysis and Critical Control Points. A plan to identify,Thermometer prevent or control hazards at critical control points. Records and

verifies that the system is working.

_____ 4. Lactic Acid D. During slaughter the GI tract and organs are removed.Rinse

Short answer and fill in the blank: Write short answers or fill in the blank to the followingquestions and statements. Use complete sentences when answering questions.

1. How is HACCP critical to the inspection of meat slaughtering plants?

2. Ground beef needs to be cooked to a temperature of_________to be safe from pathogens.

3. List three safety steps when cooking ground beef.

a.

b.

c.

Name

Class/Period

Date


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4. Name two changes in the meat slaughtering process since 1906 and Upton Sinclairsbook, The Jungle.

5. Can federal agencies inspect every food product that comes off the manufacturing line?What do they do?

6. ____________________ and ______________________ are keys to manufacturing practices in

assuring safe meat.


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Quiz 11 Key

Unit: Processing and Manufacturing

Lesson: Manufacture of Ground Beef

Matching: Match the vocabulary terms in column A with the definitions in column B. Write the

letter of the definition in column B in the space next to the terms in column A.

A B

_____ 1. HACCP A. Wash any visible fecal or microscopic compounds to the carcasssurface.

_____ 2. Evisceration B. Very accurate instrument for reading temperature of cookedfood.

_____ 3. Thermistor C. Hazard Analysis and Critical Control Points. A plan to identify,Thermometer prevent or control hazards at critical control points. Records and

verifies that the system is working.

_____ 4. Lactic Acid D. During slaughter the GI tract and organs are removed.Rinse

Short answer and fill in the blank: Write short answers or fill in the blank to the followingquestions and statements. Use complete sentences when answering questions.

1. How is HACCP critical to the inspection of meat slaughtering plants?

HACCP identifies potential food safety problems, prevents or corrects, keeps track of whatwas done, and double checks or verifies if it is working. Standard operating procedures

must be implemented to ensure cleanliness of facilities and equipment, as well as good

employee hygienic practices. FSIS (Food Safety and Inspection Service) inspectors verifythat the system is producing safe products. Their presence helps ensure that meat andpoultry are properly prepared, handled, stored, transported, and accurately labeled.

2. Ground beef needs to be cooked to a temperature of 160 F to be safe from pathogens.

3. List three safety steps when cooking ground beef.

a. Clean all utensils and equipment with hot, soapy water before and after cooking groundbeef.

b. Cook ground beef until the internal temperature is 160-165 F.

c. Use a clean plate to hold cooked meat (do not use the same plate used for raw meat).

4. Name two changes in the meat slaughtering process since 1906 and Upton Sinclairsbook, The Jungle.

C

D

B

A


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President Roosevelt passed the Pure Food and Drug Act and the Meat Inspection Act toeliminate the atrocious conditions in the meat packing plant.

HACCP was formed to identify hazards in manufacturing plants. All plants must implementstandard operating procedures to ensure cleanliness of facilities and equipment, as well asemployee hygienic practices.

EPA: Environmental Protection Agency sets the amount of pesticides that can be used byfarmers and sets water quality standards.

FDA: Food and Drug Administration inspects food processing plants, enforces labeling,additive, sanitation, and pesticide regulations.

State Board of Health inspects food processing plants, grocery stores, and all places thatserve food, enforces labeling, additive, sanitation, and pesticide regulations.

5. Can federal agencies inspect every food product that comes off the manufacturing line?What do they do?

No, federal agencies inspect random samples for quality control. Dangers to consumers areoften from unseen bacteria.

6. Cleanliness and refrigeration are keys to manufacturing practices in assuring safe meat.