Fight Spoilage & Keep Foods Fresh Longer! Part 3
Environmental control of storage conditions is another frequently used method of food preservation. Apple growers and processors rely heavily on this type of preservation. Apples are generally harvested from late summer through fall yet, thanks to technology, are available for most of the year. Apples are stored in environmentally controlled chambers in which the temperature, humidity, and gases are precisely controlled. This helps to delay ripening, rotting, changes in flavor and texture, and the growth of microorganisms.
Packaging protects foods from the actions of microorganisms and pests. It also protects them against the environmental enemies oxygen, light, and moisture. Numerous methods of packaging have been devised, in part to protect foods from spoilage. Packaging ranges from the familiar cans and bottles to much more elaborate containers and materials. Specific types and combinations of plastics and paper provide barriers against the infiltration of gases, moisture, and light. Packaging made of such material provides the protection of bottles and cans without all the weight. Vacuum and inert gas packaging are recent innovations that combine barrier plastics with the technology of environmental control. Here, foods are packed under a vacuum or the package is flushed with a specific mixture of gases, prior to sealing.
The acts of salting, pickling, and drying foods result in conditions that are unfavorable to the growth and often the survival of microorganisms. Acidity, high salt concentrations, and low moisture concentrations are lethal to all but a few specialized microbes. For example, dried, salted meat such as jerky doesn't contain enough water to support the growth of bacteria. However, certain molds that exist in the environment will eventually attack it unless it is protected by packaging.
Fermentation is another way in which foods are preserved. The combination of acidity and alcohol in fermented foods makes them inhospitable to most bacteria. As usual, there are a few exceptions. If wine, beer, or ciders are exposed to oxygen and environmental contaminants, certain bacteria will eventually turn them into vinegar. Some fermented foods, such as yogurt, don't contain alcohol, but do contain other protective factors. Yogurt is highly acidic and it contains a high concentration of live bacteria that guard against infection. The friendly bacteria in yogurt are not harmful to the consumer. They do however, aid in its preservation and are actually beneficial to the consumer. Bacteria in yogurt help to protect against the invasion of harmful bacteria in the gut.
Despite all the other means of preservation available today, it is often necessary to add chemical preservatives to certain foods. An example of a chemical preservative is BHT. This chemical protects fatty foods from oxidation which causes rancidity. Another example is sodium benzoate, which is added to soda and fruit juices to inhibit microorganisms. Since consumers are becoming increasingly concerned about the presence of chemical preservatives in food, manufacturers are working to develop alternate means of preservation. Many manufacturers proudly proclaim that their foods contain no artificial preservatives.
Because there are many types of food with differing characteristics and many causes of food spoilage, multiple means of preservation have been developed. Often, it is necessary to combine several preservation methods to keep a particular food from going bad. The method used for preservation must be tailored to the specific food and its associated spoilage problems. Recent advances in food preservation have resulted in more variety and convenience and greater accessibility for the consumer. They have also resulted in safer and better quality food.