Food Safety Tools
Bimetal Dial Pocket Thermometer
The earliest surviving bimetallic strip was made by the 18th-century clockmaker John Harrison, who is generally credited with its invention in 1759. A bimetallic strip is used to convert a temperature change into mechanical displacement.
The bimetal dial pocket thermometer used by sanitarians and chefs was introduced in the 1940s. Within a decade, the bimetal dial thermometer replaced the liquid-filled, armor-clad thermometers that were previously used.
This 1-in. dial pocket thermometer with a 2-in. bimetal coil was manufactured by Weston Instruments, Co. from Newark, New Jersey. This thermometer was issued to New Jersey sanitarians from the 1950s to the late 1960s.
Electric Branding Iron
The Texas Department of Health used these branding irons to indicate crated, packaged, and processed foods were inspected and fit for consumption. The above example is a Model 84 iron, manufactured by The Great Lakes Corporation in Chicago, Illinois. The Great Lakes Corporation also manufactured food packaging equipment.
This branding iron was used in the 1950s. The brand reads: TEXAS INS. & PSD. DEP. OF HLTH 651.
Fat Percentage Measuring Kit
Before the development of the DSC compact digital fat analyzer, sanitarians and meat inspectors used the Hobart F101 Fat Percentage Measuring Kit extensively. This portable field kit was used to rapidly estimate fat content of meat, which was followed by taking a legal sample for further analysis if necessary.
The original Model F100 field kit was patented in July 1960 and introduced to the regulatory community shortly thereafter. The F100 had an integrated timer and cooking element to help separate the moisture and fat from the protein. A newer model F101 separates these two components and improved the configuration of the exhaust for better heat dissipation. The F101 is still marketed and available today. The kit weighs 20 pounds and was designed to be completely portable. The glass equipment was standard and easily replaceable, thereby making it an excellent field instrument.
The F101 kit was designed to determine the percentage of fat content of a 2-ounce (56.7 g) sample of ground beef containing from 10–40% fat. Each test takes 15 minutes and is accurate within 卤1%. Although not indicated by the manufacturer鈥檚 specifications, sanitarians also used the kit to determine the fat content of sausage and other meat mixtures such as meatloaf and meatballs; however, these samples were tested for screening purposes only.
The Hobart Electric Manufacturing Company was founded in 1897 in Troy, Ohio, by Clarence Charles Hobart. At that time, the company manufactured electric dynamos and motors. In 1903, the company began making electric coffee mills and by 1905, had expanded its product line to include the first electric meat chopper. In 1913, The Hobart Electric Manufacturing Company was reorganized, and its name changed to The Hobart Manufacturing Company. In 1974 the name changed to Hobart Corporation. Since 1999, the Hobart brand has been part of ITW Food Equipment Group, LLC, a subsidiary of Illinois Tool Works, and remains a leading manufacturer of commercial food preparation equipment, commercial dishwashers, and weighing and wrapping equipment. Hobart also is one of the major contributors and participators in NSF food equipment standards development.
Food Inspection Kit
The Food Inspection Set, Veterinary was issued to members of the Army Veterinary Corps who were charged with ensuring food safety. The set contained the essential tools to examine packaged foods upon delivery such as a hammer and pry bar, tin snips, awl, two bimetal thermometers, and a pocket rule. The tools in the set allowed the veterinarian in charge of food safety to inspect food for freshness, temperature, quality, and sanitation before accepting food deliveries.
This set dates from the Vietnam War era.
Inspection Stamp
The inspection stamp pictured above dates to the 1950s and was used by the DC Health Department. The East Coast style shield is made of brass and is affixed to a wooden handle. In addition to the name of the health department at the top of the stamp, the words "INSPECTED AND PASSED" surround the numeral 鈥�1鈥� on the lower half of the stamp.
Lactometer
The lactometer was standard issue to sanitarians for most of the last century. It is used to measure the density of cow鈥檚 milk by measuring the amount of water in the milk, thereby adjudging the purity of the milk. The specific gravity of milk does not give a conclusive indication of its composition since milk contains a variety of substances that are either heavier or lighter than water. By using a lactometer, however, the deeper the bulb sinks, the more dilute or impure the milk is.
The lactometer has correction factors sealed in the glass. For every change in temperature by 10 掳F, there is corresponding change of a 1.0 lactometer reading. After applying a correction factor, the reading is known as a corrected lactometer reading.
The instrument pictured (circa 1920鈥�1930) with its wooden, internally padded carrying case (not shown), is marked 鈥淣.Y. Board of Health Lactometer temp: 60掳 Fahrenheit.鈥� This statement indicates that milk tested at that temperature requires no correction factor.
Melon Tester
The original folding fruit knife (aka melon tester) was made of silver and mother-of-pearl in the late 1700s in England. While silver is relatively soft, it is resistant to citric acid and does not rust. The stainless-steel fruit knife became popular in the 1930s. They were standard issue for sanitarians and are still one of the most useful tools when conducting food inspections.
These specialty knives are made with long, skinny, spear blades (4.5 in. blade). They are used to get a sample from deep inside the product such as fruit, vegetables, and meat. The inspectors can then examine the smell, texture, and color of the product.
The knife pictured above was issued in 1965 and is typical of most melon testers. The melon testers were given as advertising products, imprinted with the company logo. This knife was made by Colonial Cutlery in Providence, Rhode Island, which was founded in 1926 and is the leading manufacturer of switchblades and utility knives.
Milk Sample Bottle
This milk sample bottle is from the 1960s. It was manufactured by the Mojonnier Bros. Co. in Chicago, Illinois. These half-pint milk sample testing bottles with a rubber stopper were routinely used by sanitarians who inspected dairy plants. They were most often used for milk fat and pasteurization assays.
The Mojonnier bottle was developed and patented in 1921 and is still in use.
Portable Egg Candler
The image above is a portable galvanized steel egg candler that was manufactured sometime after 1922.
The egg candler was used by sanitarians to determine the quality and grade of the egg. By looking at the egg鈥檚 air cell, the yolk, and the albumen (i.e., egg white), sanitarians were able to determine whether the egg should be graded AA, A, B, or inedible. An excellent description of the egg inspection process is found in the Sanitarian鈥檚 Handbook: Theory & Administrative Practice for Environmental Health published in 1977 by Dr. Ben Freedman.
The egg candler was standard equipment when inspecting farm vendors, egg wholesalers, and egg breakers.
The candler pictured above has the original bulb and is insulated with asbestos. The keyless porcelain socket was manufactured by the Knox Porcelain Corporation of Knoxville, Tennessee. The carrying handle has two screw keyways that allow it to be temporarily mounted to a wall.
Rubber Stamp Kit
This rubber stamp kit was issued by the U.S. military and was used for food inspection and veterinary practices. The kit is dated 12/1979 and has the serial number 0036 on each stamp. It was manufactured by Action Marking of River Grove, Illinois.
The kit contains two, 2 x 2-in. rubber stamps complete with identification symbols, interchangeable rubber numerals, an ink pad, and secured ink vial.
In spite of its diminutive size, the kit weighs in excess of one kilogram. From its construction, it appears to have been designed to withstand a lot of abuse while used in the field.
Trichinoscope
Early trichinoscopes were manufactured by two German companies, H. Haupner and Paul Waechter. They were introduced in the third quarter of the 19th century and produced well into the 20th century. The one pictured above was made in 1920 and saw use in New Jersey. The scope is designed to be carried in the field by the inspector.
The trichinoscope is a specialized microscope for finding Trichinella in pork. Sanitarians and meat inspectors would verify that only worm-free pork was used in lightly cooked sausage. More recently, the trichinoscope is used to ensure the safety of wild-game meat, specifically that which is served at game dinners.
A thin slice of raw meat is compressed between two glass plates known as compressoria. The specimen is examined at 40x and 100x for the nematode Trichinella spiralis. Dyes were not needed to see the cyst in larger versions of the field instrument.
A more recent version of a trichinoscope kit is pictured to the left in its original wrapping. The compact kit contains everything necessary to conduct the examination of the raw meat, including a hand-held, low power scope and a dye container. These kits were manufactured post-war by PZO in Warszawa, Poland, and issued to meat inspectors and veterinarians.