Ketchup

Background

Ketchup, a tangy, seasoned tomato sauce, is one of America's favorite condiments. Although ketchup, also spelled catsup, is used primarily as a relish for hamburgers, hot dogs, and french fries, it is also a common ingredient for sauces, meatloaf, beans, and stews. During the mid-1990s the sales of ketchup exceeded $400 million annually.

The tangy sauce originated in ancient China as a brine of pickled fish or shellfish called "ke-tsiap." Neighboring countries adopted their own variations of "kechap" consisting of fish brine, herbs, and spices. In the late 1600s, English sailors visiting Malaysia and Singapore were so impressed with the sauce that they took samples home. English cooks attempted to duplicate the spicy sauce, but without access to some of the exotic Asian ingredients, they improvised with cucumbers, mushrooms, nuts, oysters, and other variants.

One hundred years later, New Englanders created the definitive tomato ketchup when Maine seamen returned from Mexico and the Spanish West Indies with seeds of an exotic New World fruit called tomato. The tangy tomato ketchup quickly became a popular sauce for codfish cakes, meat, and other foods.

Making ketchup at home was a tedious, day-long process. The tomato mixture, cooked in heavy iron kettles at wood-burning stoves, required constant stirring to prevent it from burning. Scouring the preserving kettles meticulously was also no easy task. To the relief of many homemakers, ketchup became commercially available in the second half of the 1800s.

H.J. Heinz Co. developed one of the first leading brands of mass-marketed ketchup. The classic narrow-neck design of the Heinz ketchup bottle established the norm for the industry. The narrow-neck bottle simplified pouring the ketchup and minimized contact with air, which could darken the sauce. Glass was an ideal container because it was inert and did not react with the ketchup, and the clear glass allowed the consumer to see the product. Initially, the bottles were sealed with cork, dipped by hand into wax to prevent aeration, and topped with foil to further protect it from contamination. By the turn of the century, screw caps provided a more convenient closure. In the 1980s, plastic squeezable containers revolutionized ketchup packaging and soon outsold glass containers. Plastic was not only more convenient than glass for pouring the thick sauce, but also safer. Ten years later, in response to environmental concerns, recyclable plastic containers were also developed.

Raw Materials

The main ingredients of ketchup are tomatoes, sweeteners, vinegar, salt, spices, flavorings, onion, and/or garlic. The types of sweetener used are usually granulated cane sugar or beet sugar. Other sweeteners include dextrose or liquid sugar in the form of corn or glucose syrup. The white vinegar, commonly 100-grain distilled, helps to preserve the ketchup. The spices commonly used to enhance the flavor of the tomatoes are allspice, cassia, cinnamon, cayenne, cloves, pepper, ginger, mustard, and paprika. Some manufacturers believe that whole spices produce a superior, more mild flavor than ground spices or spice oils. More modern processes use premixed or encapsulated spices, which are easier to use but more expensive. Whatever the form, spices must be of a high quality.

The various brands of ketchup have slightly different formulas, which vary primarily in the amounts of spices or flavorings. Thicker consistencies require a greater ratio of sugar and spices relative to the tomato juice. Occasionally formulas must be slightly adjusted according to variations in the acid and sugar content of tomatoes, which occurs with changes in growing conditions and types of tomatoes.

The Manufacturing
Process

Developing quality tomatoes

• 1 Ketchup manufacturers must seek out the best quality tomatoes for their product. Tomato varieties are developed which are superior in color, flavor, texture, and yield. Consistency is an important factor, as slight variations in tomato characteristics could alter the flavor and color of the finished product.

Preparing tomatoes

• 2 Tomatoes are harvested mechanically between June and July. The fruit is commonly conveyed by water from the trucks into a flume, or an inclined channel. The water method washes the tomatoes and protects them from bruising while they pass from the truck to the factory. The U.S. Department of Agriculture or state inspectors approve and grade tomatoes to meet initial requirements. The tomatoes are sorted, washed, and chopped. Next, precooking, or scaling, in stainless steel vats preserves the tomatoes and destroys bacteria.

Pulping

• 3 The chopped and precooked tomatoes are pumped into pulping machines, or cyclones, which separate seeds, skins, and stems from the pulp. The pulp and juice are filtered through screens and processed further into ketchup, though some may be stored in a paste for use later in the year.

Adding ingredients and cooking

• 4 The pulp is pumped into cooking tanks or kettles and heated to boiling. Foaming may occur if fresh tomato pulp is used, but can be corrected with anti-foaming compounds or compressed air. Precise amounts of sweeteners, vinegar, salt, spices, and flavorings are added to the tomato pulp. Most spices are added early in the cooking process. To avoid excessive evaporation, volatile spice oils and vinegar must be mixed in later. Onions and garlic can be mixed in with the spices, placed in a separate bag, or chopped and added to the pulp. Salt and sugar may be added at any stage of cooking though it is better to add sugar later to prevent burning. The mixture cooks for 30-45 minutes and is circulated by rotating blades installed in the cookers. The temperature must be carefully regulated to insure absorption of the ingredients without overcooking, which creates a flat body.

Finishing

• 5 Once the cooking is complete, the ketchup mixture passes through a finishing machine. Finishers remove excess fiber and particles through screens, creating a smoother consistency. The ketchup passes to a holding tank before further processing.
• 6 The ketchup may be milled at higher temperatures and pressures to achieve a smoother consistency.

Removing air

• 7 The ketchup must be de-aerated to prevent discoloration and growth of bacteria. Excess air might also create unattractive air pockets and impede the closure process.

Filling

• 8 To prevent contamination, the ketchup passes from the receiving tanks to the filling machines at a temperature not lower than 190°F (88°C). The containers are filled with the ketchup and immediately sealed to retain the freshness of the product. Ketchup containers come in various sizes and shapes, including 14-oz. bottles, No. 10 cans, pouch packs, room-service sizes, and single-serve packets.

Cooling

• 9 The containers must be cooled to prevent flavor loss through stack burning, which occurs when ketchup stays at high temperatures after cooking is complete. Containers of ketchup may be cooled in cold air or cold water.

Labeling and packing

• 10 Finally, the ketchup containers are labeled and coded with product information, including ingredients, date and location of manufacture, and shelf-life. The bottled ketchup may be inspected again before shipping. The entire process of ketchup manufacturing generally takes two to three hours.

Quality Control

Some of the commonly used preservatives during the 19th century included benzoate of soda, borax salicylic acid, benzoic, and formaldehyde, all of which could pose health risks when consumed in large quantities. A series of Pure Food Laws beginning in 1906 banned the use of the harmful preservatives.

In 1940, the U.S. government established a "Standard of Identity" for ketchup as tomato-based. Thus consumers could tell from the label that the product was made of tomatoes, since ketchup could also be made from other foods, including bananas, beets, or mangoes.

The quality of ketchup is insured by taking samples of the product during various stages of production. Tomato growers must comply with regulations set by the Environmental Protection Agency and the Food and Drug Administration regarding the use of fertilizers and pesticides. Increasing concern in the closing decades of the 20th century led to increased use of natural fertilizers and pesticides. Inspection is necessary of the tomatoes, ingredients, and of all processing equipment which comes into contact with the product.

Oxidation of ketchup can darken the color of ketchup, but de-aeration of the sauce during manufacture can prevent this problem. However, once the containers are opened, oxidation may still occur. Although the acidity of ketchup preserves the sauce, manufacturers recommend that once containers are opened they should be refrigerated to prevent deterioration of the ketchup color, flavor, and quality.

To maintain consistency in color and flavor, manufacturers determine the concentration of tomato solids in the mixture, since about one-third of the ketchup's acidity and sugar content depends on the amount of solids. The ketchup Grades A through C must conform to specific concentrations. The quality of the ketchup can be measured by its physical consistency, or body, which refers to the ability of the ketchup to retain its liquid in suspension. The slower the rate, the higher the grade of the ketchup. For instance, the Bostwick Consistometer, recommended by the USDA, set Grades A and B at flow rates at less than 4 inches (10 cm) in 30 seconds at 68°F (20°C).

The Future

Ketchup manufacturers continue to improve the quality of ketchup by developing tomato strains that are superior in color, flavor, and firmness. Tomato hybrids are also engineered to improve resistance to disease and rot, thus decreasing the reliance on chemical pesticides.

In the 1990s, in response to consumer demand for more healthful foods, ketchup manufacturers created low-calorie, low-salt ketchup alternatives. The increasing popularity of Spanish salsas and marinades also influenced manufacturers to develop salsa-style ketchups which were lower in sugar content. Packaging technology continues to

improve as consumers demand safer, more convenient, and recyclable containers.