=Peppers.=--Black pepper is made from the whole berry; white pepper is made from the same berry with the outer husk removed. The adulterants are usually inert and harmless substances, such as flour, mustard, or linseed oil; their presence is obviated by the use of the whole peppercorns, ground as needed.
=Red Pepper.=--This may be adulterated with red lead; when pure it will be entirely suspended in water; if a sediment falls it is probably red lead.
=Mustard.=--Practically all of the adulterants of mustard can only be detected by intricate chemical tests. The presence of turmeric may be detected by the appearance of an orange-red color when ammonia is added to a solution of the sample.
=Tomato Catsup.=--Artificial dyestuffs are common, giving a brilliant crimson or magenta color. Such catsup does not resemble the natural dull red or brown color of the homemade article.
Preservatives, such as boric, salicylic, or benzoic acids and their salts, are sometimes added. While their presence cannot be condoned, yet they are usually present in small amounts and therefore practically harmless.
=Pickles.=--These should be of a dull-green color. The bright emerald green sometimes observed is due to the presence of the salts of copper; this may be proved by dipping the blade of a penknife in the liquor, as described under the heading of "Canned Goods."
Alum is sometimes used as a preservative and in order to make the pickles crisp. Its presence may be demonstrated by means of the "logwood" test mentioned under the heading of "Flour."
=VINEGAR.=--Cider vinegar is of a brownish-yellow color and possesses a strong odor of apples.
Wine vinegar is light yellow if made from white wine, and red if made from red wine.
Malt vinegar is brown and has an odor suggestive of sour beer.
Glucose vinegar has the taste and odor of fermented sugar.
Molasses vinegar has the distinctive odor and taste of molasses.
=OLIVE OIL.=--Pure olive oil has a pleasant, bland taste and a distinctive and agreeable odor, unmistakable in character for that of any other oil. The finest virgin oil is pale green in color, the cheaper grades are light yellow.
The adulterants consist of cotton-seed, corn, mustard, and peanut oils.