Tag Archives: light

Light, Another Enemy of Food Storage

Light is the least understood enemy of food storage.  Exposure to light can cause foods to spoil faster.  Both natural and artificial light can cause photodegradation, according to the Department of Food Science and Human Nutrition at Clemson University.  Exposure to sunlight, fluorescent light or incandescent light can cause photodegradation.

The light sensitivity of a food depends on many factors including the:

  • light source strength and type of light that it emits;
  • distance of the light source from the food;
  • length of exposure;
  • optical properties of the packaging materials;
  • Whether the food is solid or liquid.

Light normally penetrates only the outer layer in a solid food, typically causing discoloration on its surface.  Light can penetrate liquids more deeply and affect more constituents because of mixing and agitation.

When foods and spices like chili powder, which are normally brightly colored, have faded, their flavor and nutrient content have decreased.  Deterioration from light exposure effects  light sensitive constituents, like those listed below.

  • Vitamins — Vitamin A, Vitamin B12, Vitamin D, Folic Acid, Vitamin K, Vitamin E, Pyridoxine, Riboflavin
  • Pigments — Anthocyanins, Carotenoids, Chlorophylls, Myoglobin, Hemoglobin
  • Amino Acids — Tryptophan, Phenylalanine, Tyrosine, Histidin
  • Fats — Unsaturated fatty acids, Phospholipids

According to the University of Minnesota, the riboflavin content in enriched macaroni has been known to drop by 33 percent after exposure to light for one week.  Oils and fats seem to be practically sensitive to the effects of light.

Wet pack foods in metal cans do not need to be protected from light.  Food in glass jars will need protection.  Special care should be taken with home canned food in mason jars.  They should be store in dark rooms, containers or cardboard boxes.  The boxes the jars come in work well.

Dry foods packed in plastic buckets should be kept out of bright lights, unless the contents are packed in Mylar bags.  Personally, we try to keep all our foods in dark cool dry and insect free areas.


Posted in food storage, preserving foods | Tagged , , | Leave a comment

Enemies of Food Storage

Food stored in temperature controlled area.

The first rule of food storage can be summed up in the acronym HALT.  It stands for the four enemies of good food storage.  These are Humidity, Air (oxygen), Light, and Temperature.  This is the basis of all food storage

To get the maximum storage life of your food you need to protect it from these four enemies. This will also preserve the maximum amount of nutrition.

  • Store your food at constant temperature of between 40 – 70 degrees.
  • Protect your foods from exposure to moisture and high humidity.
  • Protect your foods from exposure to oxygen.
  • Store your foods in a dark area or opaque containers.

Today we will discuss temperature. Since storage temperature is one of the most important factors, perhaps a general rule might be appropriate. The lower the temperature the longer the shelf-life. Persons storing foods in a garage at an average temperature of 90°F should expect a shelf-life less than half of what could be obtained at room temperature (60-70°F) which in turn is less than half the storage life in cold storage (40°F)

Now for some of us this is easier said than done.  A good dry basement is always a good choice; anything below ground maintains a relatively even temperature.  But if you don’t have a basement, what is your next choice?  Avoid uninsulated garages and storage sheds, if at all possible.  On this subject, a wise man once said that if we have to use our food storage, we would wish we had stored our furniture in the garage and our food in the house. If you have to store food in the garage, store it low, near the floor, but leave a little air space between it and the concrete.  Plant some fast growing trees to shade your garage.  If possible, move your sheds into the shade.

These sheds need to be insulated and depending on where you live, placed in the shade or air conditioned.

Avoid attic areas; if you store your food in the house in temperature-controlled areas you are in good shape.  If your home gets hot, store your food low in closets and under beds etc.  Remember heat rises.

If you have to use some less desirable storage areas, use them for foods that are less likely to be damaged by heat.  Foods subject to heat damage would include most wet packed canned foods.  Food stored in hot areas should be rotated on a more frequent time schedule.

Over the next three days we will discuss the three other major enemies of food storage. Humidity or moisture, oxygen and light.


Posted in food storage, preserving foods | Tagged , , , , , , | Leave a comment