Natural Alternatives to Chemical Preservatives

Preservatives in wood

Preservatives may be added to wood to prevent the growth of fungi as well as to repel insects and termites. Typically arsenic, copper, chromium, borate, and petroleum based chemical compounds are used. For more information on wood preservatives, see timber treatment.

Preservatives in foods

Preservatives are often added to food to prevent their spoilage, or to retain their nutritional value and/or flavor for a longer period. The basic approach is to eliminate microorganisms from the food and prevent their regrowth. This is achieved by methods such as a high concentration of salt, or reducing the water content. This inhibits spoilage of the food item by microbial growth.

Preservatives may be antimicrobial preservatives, which inhibit the growth of bacteria or fungi, including mold or they can be antioxidants such as oxygen absorbers, which inhibit the oxidation of food constituents. Common antimicrobial preservatives include sorbic acid and its salts, benzoic acid and its salts, calcium propionate, sodium nitrite, sulfites (sulfur dioxide, sodium bisulfite,potassium hydrogen sulfite, etc.) and disodium EDTA. Antioxidants include BHA, BHT, TBHQ and propyl gallate. Other preservatives include ethanol and methylchloroisothiazolinone. FDA standards do not currently require fruit and vegetable product labels to reflect the type of chemical preservative(s) used on the produce. The benefits and safety of many artificial food additives (including preservatives) are the subject of debate among academics and regulators specializing in food science, toxicology, and biology.

Natural food preservation

Naturally occurring substances such as rosemary extract, hops, salt, sugar, vinegar, alcohol, diatomaceous earth and castor oil are also used as traditional preservatives. Certain processes such as freezing, pickling, smoking and salting can also be used to preserve food. Another group of preservatives targets enzymes in fruits and vegetables that start to metabolize after they are cut. For instance, the naturally occurring citric and ascorbic acids in lemon or other citrus juice can inhibit the action of the enzyme phenolase which turns surfaces of cut apples and potatoes brown if a small amount of the juice is applied to the freshly cut produce. Vitamin C and Vitamin E are also sometimes used as preservatives.

Health concerns

Some modern synthetic preservatives have been shown to cause respiratory or other health problems. For example sulfites are commonly used in wines and some dried fruits or vegetables and are known as possible irritants to people with asthma. In one study, children exhibited increased hyperactivity after consuming drinks containing sodium benzoate or artificial food color and additives. Prior studies were however inconclusive.

The following table shows the type of food preservatives used, the type of food products they are used in, and the permissible limits for their use.

Food Preservative	Type of preservative	Type of food products	Maximum Permissible limit
Benzoates and sorbates	Antimicrobial	Pickles, margarine, fruit juices, jams, cheese	200 ppm (200 parts per million)
Propionates	Antimicrobial	Bakery products, cheese, fruits	0.32 percent
Sulfites and sulfur dioxide	Antimicrobial	Dry fruits and fruits, molasses, wine fried or frozen potatoes, prevent discoloration in fresh shrimp and lobster	200-300 ppm
Nitrites and nitrates	Antimicrobial	Meat products	100-120ppm
Propyl gallate	Antioxidant	Baked foods, meats	200 ppm
BHA (butylated hydroxyanisole) and BHT(butylated hydroxytoluene)	Antioxidants	Baked foods and snacks, meats, breakfast cereals, potato products	100 ppm for meat products, 50 ppm for breakfast cereals and potato products
Tert-Butylhydroquinone (TBHQ)	Antioxidant	Baked foods and snacks, meats	100 ppm
Erythorbic acid (iso-ascorbic acid) and citric acid	Antienzymatic	Soft drinks, juices, wine, and cured meats	200-350 ppm

Note: Permissible limits for use of food preservatives vary depending on the food product, from country to country.

Natural Alternatives to Chemical Preservatives

Extracts from culinary ingredients such as green tea, grape seed and spices could be used instead of chemical preservatives as a way to protect against foodborne pathogens like Listeria, according to researchers at the University of Arkansas.

A newsletter from the Food Safety Consortium at the University of Arkansas Division of Agriculture recently reported that food processing companies might soon have such natural alternatives.

In a series of trials, researchers from the University of Arkansas said they applied extracts from natural sources including green tea, grape seed, and nisin, a bacteriocin recognized as a safe food preservative, to chicken and turkey hot dogs. In performing the experiment, researchers used a combination of 75 percent of the chemical preservative and 25 percent natural plant extracts.

According to Navam Hettiarachchy, the University of Arkansas food science professor who supervised the project, the results were encouraging.

When combined with lower levels of chemical preservatives, the natural plant extracts in green tea and grape seed inhibited the growth of Listeria monocytogenes to undetectable levels, Hettiarachchy said.

Importantly, Hettiarachchy explained that “the chemical preservatives can be partially or wholly replaced by natural plant extracts when the extracts are combined with other technologies such as heat treatment, electrostatic spraying or nanotechnology.”

She added of those three technologies, nanotechnology would most likely work best as a delivery system for the natural antimicrobials.

“If we can deliver these antimicrobials in nanoparticles, we will have better pathogen inhibition at a much lower concentration of the antimicrobial over a longer period of time,” Hettiarachchy said. Essentially, this would allow for the least amount of plant extracts to be used with the greatest capacity for pathogen reduction.

This development could prove to be advantageous not only for food processors, but for consumers as well.

Currently, food preservation systems often use chemicals and heat treatments to reduce the risk of bacterial food poisoning outbreaks and food spoilage, but chemicals can alter the taste of the product and, moreover, can compromise food safety.

The findings of Hettiarachchy’s research team indicate that food can instead be treated with natural substances in order to eliminate the risk of potential pathogens during the processing stage, creating a benign alternative to the use of chemicals.

The Food Safety Consortium, established by Congress in 1988 through a special Cooperative State Research Service grant, works on the pressing technological needs of the food industry.

Its primary function is to develop the necessary tools for a safe food supply, including “technology to rapidly identify contaminants, methods to evaluate potential health risks, risk-monitoring techniques to detect potential hazards in the food chain, and the most effective intervention points to control microbiological or chemical hazards.”

Consisting of researchers from the University of Arkansas, Iowa State University and Kansas State University, the Consortium allows each university to focus its studies on a particular animal species. For instance, scientists at the University of Arkansas concentrate on the study of poultry, while Iowa State University targets pork and Kansas State University, beef.

The food industry presents a great demand for technology that would improve food safety. It wants what is considered to be cutting-edge technology. Hettiarachchy is confident the use of nanotechnology to introduce natural antimicrobials to meat would provide just that. “The food processing companies are interested in the state-of-the-art delivery system with the natural antimicrobial extract for better pathogen control,” she added.

Before food processing companies adopt natural antimicrobials for use in their products, however, further development will be required. As Hettiarachchy confided, “Industry takes time to decide.”

Good & Bad Preservatives

Most ingredient lists read like college chemistry books. Everyday foods like “wheat” and “flour” are followed by an eyeball-bending, tongue-twisting list of organic and inorganic chemicals — poly-this, dextro-that, carbonate-the-other. Most of these confusing compounds are thrown in there to keep your Wonder Bread from breeding wondrous bacteria or your Power Bar from emitting a powerful stench. Most of these preservatives are FDA approved and wholeheartedly embraced by manufacturers. But not all of them are totally safe. In this article we’ll winnow the harmful additives from the innocuous ones and feed you the wholesome information you’ll need to decipher any ingredient list you encounter in the future.

Тhe good

Preferred preservatives

The following preservatives are, according to the FDA, completely safe for consumption. They aren’t known to cause allergic reactions or adverse health affects when used in small quantities. Most are natural — either squeezed out of Mother Nature’s products or built, chemical by chemical, to be just like them. And, believe it or not, some of them are actually good for you.

Vitamin C

That’s right, in addition to being an essential vitamin, a potential cancer fighter and a great nutritional supplement, good old vitamin C is a great preservative. The same properties that make it a super vitamin — mainly its ability to keep oxygen from wrecking shop — also keep foods fresh and colorful.

Where it’s found: Because it does double duty as a preservative and as a vitamin, vitamin C (known by its technical name, ascorbic acid, on ingredient lists) is used in a surprising number of foods. It’s found in cured meats such as bacon and ham, for instance, and many fruit juices. It’s also put in cereal flours, jellies and preserves, canned mushrooms, and artichokes.

Citric acid

Citric acid is vitamin C’s cousin and is an equally impressive natural preservative and additive. As far as acids go, it’s pretty weak — incapable of eating a hole in a tabletop, for instance. Still, it works wonders in food, where it helps to keep bacteria and mold at bay. Oddly enough, most citric acid isn’t derived from citrus fruits. It’s manufactured one molecule at a time by the mold — aspergillus niger. The mold happily produces citric acid as long as it has a nice supply of sucrose (sugar). Citric acid is found naturally throughout the body and causes no side effects in 99.9% of the population. A very, very small portion of the population is intolerant of the stuff, but the condition is so rare as to be nearly nonexistent.

Where it’s found: Citric acid is used extensively in soft drinks as a preservative and to enhance flavor. The acid adds a sour punch to whatever it’s in and turns up in many foods that need an extra sour kick. Citric acid is also used in some household cleaners to balance pH levels.

Дата добавления: 2015-10-28