Taste Sensitivity

Taste Sensitivity
People vary in their sensitivity to different tastes. Sensitivity depends on the length of time allowed to taste a substance.

Sweet and slat tastes are detected quickly (in less than a second), because they are detected by taste buds in the tip of the tongue, in addition, they are usually very soluble compounds.

Bitter compounds, on the other hand may take a full second to be detected because they are detected at the back of the tongue.

The taste may linger, producing a bitter aftertaste.

Sensitivity to a particular taste also depends on the concentration of the substance responsible for the taste.

The threshold concentration is defined as the concentration required for identification of a particular substance.

The threshold concentration may vary from person to a person: some people are more sensitive to a particular taste than others and therefore are able to detect it at a lower concentration.

Below a threshold concentration, a substance would not be identified but may affect the perception of another taste.

For example subthreshold salt levels increase perceived sweetness and decrease perceived acidity, whereas subthreshold sugar concentrations make a food taste less salty than it actually is.

Although it is not clear why, flavor enhancers such as MSG also affect taste sensitivity by intensifying a particular taste in a food.

Temperature of food also affects its flavor. Warm foods generally taste stronger and sweeter than cold foods. For example, melted ice cream tastes much sweeter than frozen ice cream.

There are two reasons for the effects of temperature on flavor. The volatility of substance is increased at higher temperatures, and so they smell stronger.

Taste bud receptivity also is an important factor. Taste buds are most receptive in the region between 68 and 86 degree F and so taste will be more intense in this temperature range.

Psychological factor also affect taste sensitivity and perception. Judgments about flavor are often influenced by preconceived ideas based on the appearance of the food or on previous experience with a similar food.

For example, strawberry flavored foods would be expected to be red. However, if colored green, because of the association of green foods with flavors such as lime, it would be difficult to identify the flavor as strawberry unless it was very strong.

Color intensity also affects flavor perception. A stronger color may also cause perception of a stronger flavor in a product, even of the stronger color is simply due to the addition of more food coloring.

Texture also can be misleading. A thicker product may be perceived as tasting richer or stronger simply because it is thicker and not because the thickening agent affects the flavor of the food.

Other psychological factors that may come into play when making judgments about the flavor of foods include time of day (for example, certain tastes are preferred at breakfast time), general sense of well being, health and previous reactions to a particular food or taste.
Taste Sensitivity

Bacterial Food Poisoning

Bacterial Food Poisoning
The following bacteria frequently cause food poisoning:
-Salmonella
-Staphylococcus aureus
-Clostridium perfringes
-Bacillus cereus

The following bacteria cause food poisoning less frequently:
-Clostridium botulinum
-Some strains of Escherichia coli

All bacteria have two names. The generic name is written first and with a capital letter, e.g. Clostridium, Bacillus.

The specific name is written with a small letter after generic name, e.g. perfringes, cereus.

Bacteria with the same generic name have similar characteristics, e.g. shape, oxygen requirements, enterotoxin production and spore formation.

There are approximately 2000 species of the Salmonella genus (e.g. Salmonella typhimurium, Salmonella enteriditis, Salmonella hadar, Salmonella newport) but most of them cause food poisoning it is usual to talk about Salmonella food poisoning without distinguishing which species is actually cause.

Salmonella, Staphylococcus aureus, Clostridium perfringes and Bacillus cereus are all common cause of food poisoning in the UK and many other countries.
Bacterial Food Poisoning

PH Control Substances

PH Control Substances
Natural or synthetic acid or alkali ingredients change or maintain the initial pH of a product.

For example, acidulents flavor, preserve and regulate pH.

The acid ingredients regulate by lowering the pH and preserve foods by inhibiting microbial growth.

Regardless of the acid level of food ingredients, food acids are incorporated into foods in order maintain a constant acid level.

Natural acids include the following acetic acid or vinegar and citric acid from citrus, which control unwanted trace metals otherwise catalyzing oxidation reactions; malic acid (an organic acid from apples and figs); and tartaric acid (a weak acid).

These acids may be added to foods to impart flavor and control tartness.

Lactic acid present in almost all living organisms, is an acidity regulator and is used in balancing the acidity in cheese making, as well as adding tartness to many other foods.

The acid salt calcium propionate is added to control pH of breads.

Sodium lactate (the salt of lactic acid) may be used in processed meat and poultry products.

Examples of alkaline ingredients include sodium bicarbonate (baking soda), an ingredient that balances the acid component of baking powder, sodium hydroxide, used in modified starches, and potassium hydroxide.

Alkaline compounds are used to neutralize excess acid that otherwise could produce unwelcome flavors. In food they leaven and soften hard water.
PH Control Substances

Adulteration

Adulteration
Adulteration is not difficult to determine since there are tests that can be made to detect sources of contamination such as rodents (hair, pellet, or urine), insects, dirt and other detritus.

Also, if a food is putrid this can be detected by the ordinary human sense, a fact this is well known and accepted.

However, the detection of decomposition is not easy and often scientist do not agree on what constitutes decomposition of a particular food. Citations based in the development of a food, therefore, frequently have to be settled in court.

Regarding activities that may be present in foods, the administration and the industry known that certain chemicals are toxic and cannot be added to foods at all.

The FDA has a GRAS (generally regard as safe) list that specifies which chemicals may be added for foods and, in many instances how much may be added to a particular food.

Many compounds on this list come under what is called the Grandfather Clause, these chemicals having been used in foods for years with no apparent ill effect.

For some chemicals that can be added to foods and for any new chemicals that will be added, tests have been or will be made by feeding several kinds of animals a diet containing the chemical over a period of several generations.

The results of such tests are determined by observations in the weight and general health of the animals, as well as their ability to breed, and on autopsies and chemical tests for specific enzyme activities and so on.

Time, trained personal and special facilities are required for testing as new food additive.

This is a very expensive process, requiring as a rule, the outlay of several hundred thousand dollars and no producer of such a new compound is apt to initiate such testing, which must satisfy the FDA, unless he is certain that the new additive will provide specific advantage and have great utilities.
Adulteration