Preservatives: Their Function and Safety

Published Monday 16 of March, 2009

By Jane Leon, Doctor of Veterinary Medicine (DVM)

Distinguished Graduate of Cornell University College of Veterinary Medicine

    Preservatives are used in foods to prolong their usable life.  Every food manufacturer uses some type of preservation technique to allow food to be transported, sold, and stored without spoiling.  Although we think of preservatives as a modern advance, mankind has been preserving food throughout recorded history.  Physical methods, such as drying and freezing, were and are still used.  Even food additives have been used for centuries.  The original added preservatives were substances such as salt, sugar, and vinegar.  These products allowed foods to be pickled, cured, and “put up” as jellies and preserves.  Today, we have additional preservatives to choose from, including newer, chemical additives and techniques such as vacuum packaging and pasteurization.

    Every preservation technique has pluses and minuses.  Most alter taste, texture, or nutrient levels of the food.  For example, physical techniques alter the flavor and texture of the food, and only last for limited periods of time.  Additionally, natural preservatives alter taste and texture and can be harmful if overused.  So, some salt helps preserve meat or fish, but too much salt ruins the food and is bad for the consumer.  Even pasteurization, often used for liquids, can rob a product of nutrients and is no longer effective once the product is opened.  Ultimately, there is no perfect preservative.  The key is to find the best possible preservation technique for any given food product.  

    The search for preservatives that efficaciously preserve shelf life without altering the taste and texture of the food led to the development of human-made preservatives.  These agents prevent contamination and spoilage caused by bacteria and fungi, stop decay caused by oxidation, and slow the breakdown of food.  Their use not only prevents spoilage, it maintains levels of certain nutrients, such as amino acids and vitamins.

    After much study, the preservatives sodium benzoate and potassium sorbate were chosen to preserve Dog-Wa.  The manufacturers would have loved to avoid all preservatives, providing dogs with an untouched product, but this could not possibly work, as pressed extracts of herbs must be used immediately or preserved.  Also, heat pasteurization was examined, but discarded, because the heat would destroy the delicate micronutrients and the Dog-Wa would start to break down the moment it was opened. This meant that pasteurized Dog-Wa could only be stored for a short time once opened.  This was not a satisfactory preservation technique.

    So the best possible answer was found in the use of preservatives that keep bottled Dog-Wa stable before and after the bottle is opened.  Thanks to the preservatives, you can keep an opened bottle of Dog-Wa for up to 3 months in the refrigerator.  You can even dilute Dog-Wa in your dog’s water and leave it at room temperature throughout the day, until the dog consumes it.  Dog-Wa will stay stable up to two days in the bowl, so as long as you change the water daily and add the correct amount of Dog-Wa, your dog will get the appropriate level every single day.  All of this is accomplished while preserving the vitamins, antioxidants, and other micronutrients found in the cold-pressed parsley and mint.

     Sodium benzoate and potassium sorbate were chosen because they are FDA-approved for human and animal consumption and have been in use for decades.  Sodium benzoate, naturally present in cranberries, prunes, and apples, is used to preserve salad dressings, beverages, jams, and cough syrup.  Potassium sorbate is used in wine, cheese, baked goods, dried foods, herbal supplements, and personal care products. They are added to concentrated Dog-Wa in small amounts that fully comply with federal guidelines for human consumption.  Once Dog-Wa is diluted out, per the instructions, the preservatives are actually present at levels much below the maximum levels listed by the federal government.  

    Happily, the use of preservatives allows the nutrients found in Dog-Wa to reach your dog safely.  The unopened bottle can be stored in your cupboard for two years from its date of manufacture.  And the micronutrients from the cold-pressed, fresh herbs are still present for three months after you open the bottle and store it in your refrigerator.  You get the best of both worlds – the benefits of fresh herbs with the peace of mind that comes from using a safe product.  Additionally, you have the convenience and cost- effectiveness of a bottled product that can be safely used to the very last drop.  The bottom line is that you can offer Dog-Wa knowing that the product is safe and effective due to its manufacturing and preservation process.

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