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U.S. Department of Health and Human Services

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Elemental Analysis Manual: Section 2.1 Laboratory Sample to Analytical Sample

Elemental Analysis Manual, Version 1 (June 2008)
Authors: Stephen G. Capar
Katie Egan
Richard M. Jacobs

Table of Contents

2.1.1 FOOD EDIBLE PORTION

2.1.2 CANDY PREPARATION

2.1.3 CARBONATED BEVERAGE DEGASIFICATION

Glossary


This section provides information to assist the analyst in physically preparing the laboratory sample prior to preparing the analytical sample. The purpose is to obtain the edible portion of the food and to remove dirt and other material in a manner consistent with normal consumer practices for food preparation. Care must be taken to minimize contamination from the equipment and materials used in this process.

2.1.1. Food Edible Portion 

The edible portion of most foods is obvious. However, there are foods that require special instructions for consistency in obtaining the edible portion of the laboratory sample prior to preparing the analytical sample. Under FDA's Total Diet Study, a number of special food preparation instructions have been developed. Relevant procedures from this study are listed in 2.1 Table 1 and some alternative procedures have been added.

Terminology

  1. Water — Water that meets specifications for ASTM Type I water1.
  2. Rinse — Wash with water to remove all dirt and debris.
  3. Drain — Remove excess liquid using a strainer, sieve, colander or other means appropriate for the product.
  4. Tablespoon — U.S. federal law (21 CFR 101.9(b) (5) (viii)) now defines 1 U.S. tablespoon = 15 mL. Although technically a measure of liquid volume, when used for solids (i.e., coffee), it should be measured to the flattened level of the spoon (vs. a 'heaping' or 'heaped tablespoon', which is as much as can be held in the spoon)2.
 2.1 Table 1. Preparation of Edible Portion from Laboratory Samplea
Food ProductFood Preparation
Apple, red, raw (with peel)Rinse. Do not peel. Remove and discard stem and core.
Apricot, rawRinse. Do not peel. Remove and discard pit.
Apricots, canned in heavy/light syrupDo not drain; use entire contents of can.
Asparagus, fresh/frozenRinse fresh asparagus. Drain.
Avocado, rawPeel. Remove and discard pit.
Banana, rawPeel.
Beans, green, cannedDrain.
Beans, green, fresh/frozenRinse fresh green beans. Remove and discard ends and fiber thread. Drain.
Beans, pinto, dryRinse and soak overnight according to package directions. Drain.
Beans, refried, cannedDo not drain; use entire contents of can.
Beans, white, dryRinse and soak overnight according to package directions. Drain.
Beef stew with potatoes, carrots, and onion, cannedDo not drain; use entire contents of can.
Beets, cannedDrain.
Broccoli, fresh/frozenRinse fresh broccoli. Drain.
Brussels sprouts, fresh/frozenRinse fresh Brussels sprouts. Drain.
Cabbage, freshRemove and discard outer leaves and core.
Cantaloupe, raw/frozenRemove and discard rind and seeds.
Carrot, fresh, peeledRinse fresh carrots. Peel. Cut off and discard end pieces. Drain.
Cauliflower, fresh/frozenRinse fresh cauliflower. Remove and discard stem. Drain.
Celery, rawRemove and discard outer pieces that are damaged or discolored. Remove and discard thickened stem portion and leaves. Rinse each piece.
Cherries, sweet, rawRinse. Remove and discard stems and pits.
Chili con carne with beans, cannedDo not drain; use entire contents of can.
Clam chowder, New England, condensed, prepared with whole milkAdd one soup can of whole milk.
Coffee, decaffeinated, from groundMeasure 1 tablespoon coffee for each cup of water into a drip-type coffee filter. Boil the required amount of reagent water and pour over coffee.
Coffee, from groundMeasure 1 tablespoon coffee for each cup of water in drip type coffee filter. Boil the required amount of reagent water and pour over coffee.
Collards, fresh/frozenRinse fresh collards. Remove and discard stems. Drain.
Corn, cannedDrain.
Corn, cream style, cannedDo not drain; use entire contents of can.
Corn, fresh/frozenRemove corn from cob.
Cucumber, peeled, rawPeel. Cut off and discard end pieces.
Cumber, Dill, picklesDrain.
Eggplant, fresh, peeledRinse. Drain. Peel.
Eggs, boiledPlace eggs into hot boiling water and cook approximately 5 minutes until white and yolk are set. Remove shells.
Fruit cocktail, canned, in heavy/light syrupDo not drain; use entire contents of can.
Fruit drink, from powderMix with water according to package instructions.
Gelatin dessertPrepare according to the package directions. Refrigerate and allow to gel.
Grapefruit, rawPeel. Remove and discard excess white membrane, and seeds.
Grapes, (red/green) seedless, rawRinse. Remove and discard stems.
Juice, [orange, pineapple, grape, grapefruit], from frozen concentrateFollow instructions on label for adding water to thawed juice concentrate. [Usually add 3 containers of water to 1 container of thawed juice concentrate.]
[Alternative: Thaw. Do not add water.]
Lemonade, from frozen concentrateFollow instructions on label for adding water to thawed lemonade concentrate. [Usually add 3 containers of water to 1 container of thawed lemonade concentrate.]
[Alternative: Thaw. Do not add water.]
Lettuce, iceberg, rawRemove outer leaves and core. Wash individual leaves and drain on towels.
Lettuce, leaf, rawRemove and discard outer damaged leaves and core. Wash individual leaves and drain on towels.
Mushrooms, rawRinse. Trim off end pieces and discard.
Okra, fresh/frozenRinse fresh okra. Drain. Trim off and discard stem attachment.
Onion, mature, rawRemove and discard brown outer layer and first white layer and other inedible portions.
Orange, rawPeel. Remove and discard excess white membrane and seeds.
Peach, raw/frozenRinse. Do not peel. Remove and discard pit.
Peaches, canned in light/medium syrupDo not drain; use entire contents of can.
Pear, raw (with peel)Rinse. Do not peel. Remove and discard stem and core.
Pears, canned in light syrupDo not drain; use entire contents of can.
Peas, green, fresh/frozenRinse fresh peas. Drain.
Pepper, sweet, green, rawRinse. Remove and discard seeds, core, and stem attachment.
Pineapple, canned in juiceDo not drain; use entire contents of can.
Plums, rawRinse. Do not peel. Remove and discard seeds.
Popcorn, microwave, butter-flavoredPrepare according to package directions.
Pork and beans, cannedDo not drain; use entire contents of can.
Potato, whiteRinse. Peel. Drain.
Potato, white, with skinRinse and scrub. Drain.
Prunes, driedRemove seeds.
Radish, rawRinse. Remove and discard stem attachment.
Sauerkraut, cannedDrain.
Shrimp, boiledBoil in water until done (about 10 minutes). Shell and de-vein.
Soup, [chicken noodle; tomato, vegetable beef, bean with bacon/pork], canned, condensedAdd one soup can of water.
Spaghetti with tomato sauce, cannedUse entire contents of can.
Spinach, fresh/frozenRinse fresh spinach. Remove and discard stems. Drain.
Squash, Summer, fresh/frozenRinse fresh squash. Drain. Cut off and discard end pieces.
Squash, Winter, fresh/frozenRinse fresh squash. Drain. Cut in half and remove stems and seeds. Scoop out tender flesh and mash with a fork.
Strawberries, raw/frozenRinse. Remove and discard stems.
Sweet potato, cannedDrain.
Tea, decaffeinated, from tea bagPour 1 cup boiling water over 1 tea bag in a cup. Steep for 3 minutes. Remove bag.
Tea, from tea bagPour 1 cup boiling water over 1 tea bag in a cup. Steep for 3 minutes. Remove bag.
Tomato, red, rawRinse. Remove and discard stem attachment. Leave skin.
Tomatoes, stewed, cannedDo not drain; use entire contents of can.
Tuna, canned in oilDrain. Drain as much oil as possible.
[Drain using a #10 High Density Polyethylene (HDPE) sieve. Leave product in the sieve for 2 minutes or more.]
Tuna, canned in waterDrain. Drain as much water as possible.
[Drain using a #10 High Density Polyethylene (HDPE) sieve. Leave product in the sieve for 2 minutes or more.]
Turnip, fresh/frozenRinse fresh turnips. Drain. Trim off and discard stem attachment.
Vegetables, mixed, frozen{no prep}
Watermelon, raw/frozenRemove and discard rind and seeds.

a Based on instructions used in FDA's Total Diet Study.

2.1.2. Candy Preparation 

A laboratory sample for candy products should consist of a maximum of 10, 2 lbs (0.91 kg) subsamples, preferably from the same manufacturing code. The subsamples should be sealed retail units. If the candy is packed in a sealed bag of at least 2 lbs, then the each of the 10 subsamples is a bag of candy. Otherwise, each subsample is the number of bags that provide at least 2 lbs of candy.

2.1.3. Carbonated Beverage Degasification 

Degasify carbonated beverages by ultrasonication at room temperature in a sonicating water bath for at least 30 min or until there is no further effervescence. Other appropriate means of degasification may be used.


References

1ASTM International (2006) ASTM D 1193-06, "Standard Specification for Reagent Water". Available from the ASTM website. disclaimer icon

2Wikipedia contributors. Tablespoon [Internet]. Wikipedia, The Free Encyclopedia; 2006 Aug 15, 15:48 UTC [cited 2006 Aug 26]. Available from Wikipedia. disclaimer icon