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Preservative Technical Help
The most common question we get asked is on how to extend the shelf life of baked goods. Shelf life has two aspects, first is staling. Staling is typically controlled by the use of emulsifiers, enzymes and packaging. The second aspect is mold and other bacterial control. Many feel that the simple addition of a preservative will solve all of their mold problems. This usually will not work. If you are experiencing mold problems with your baked goods, then you must first look at your processing plant. Adding preservatives will help, but unless the source problem at the plant is eliminated, your problem will resurface.
 Bakeries should closely examine the physical plant for sources of mold contamination. Typical problem areas are equipment wash down areas, coolers, packaging equipment and any area that is hard to clean and can hold product debris. Visible mold growth is a definite sign of a problem, however a problem can exist even without visible growth as these are microscopic organisms. If problems are severe and mold inhibitors are not working it will be necessary to aggressively clean and sanitize the entire area. Mold spore can easily be blown across the plant from plant ventilation equipment so the entire area will need to be cleaned. After cleaning a light spray of quaternary ammonia or chlorine bleach should be applied to all exposed surfaces. This includes: floors, walls, ceilings, equipment. The sanitizer should not be rinsed off. This will give a slight residual effect. This will need to be repeated every week during the problem spell. Do not spray sanitizer on dirty areas. It is impossible to sanitize a dirty piece of equipment. Over several weeks you should see an improvement. If not the source is outside, or in some area that you have not cleaned and sanitized.
Please remember, preservatives only slow down spoilage they do not stop it or eliminate it.. If the pH of the baked good is not in the ideal range for the preservative used (most baked goods are not), then the preservative action is very limited. The first goal should always be to minimize the amount of contamination. Once this is done the preservatives will work correctly.
Calcium Propionate and Sodium Propionate
Calcium propionate and sodium propionate are two of the most common used preservatives used in baking. Their anti microbial action is directed to molds and rope bacteria with very little effect on yeast. However, high levels of propionates will inhibit yeast and thus slow down fermentation.
Like most other preservatives, propionates are more effective with slightly lower pH levels of less than 5.5 pH. This is an important issue when dealing with chemically leaven items such as cakes, muffins and donuts as these normally have a neutral pH. Chocolate cake items typically have a pH that is even higher. It is important to acidify your cake items slightly in order to optimize the effectiveness of propionates.
Typical usage levels of calcium propionate and sodium propionate are 0.1% to 0.4% base d on flour. Levels above 0.25% based on flour are needed in most commercial applications.
Calcium Propionate is used in yeast raised items and Sodium Propionate is used in chemically leavened items due to Calcium Propionate interfering with the leavening process.
Neither Calcium Propionate nor Sodium Propionate is 'cidal' at the levels used in baking. High levels of contamination or mold spores or contamination by resistant mold spores will not not benefit from the addition of propionates. The most important first step in reducing mold growth is proper sanitation of the plant and equipment.
Sodium Benzoate and Benzoic Acid
These two are basically the same as sodium benzoate produces benzoic acid once dissolved in water. Sodium benzoate is usually used since sodium benzoate is 180 times more soluble in water than benzoic acid.
Benzoates are typically used acidic items such as jams, jellies, beverages, dressings, fruit fillings and sauerkraut. It is effective against yeast, some molds and some bacteria. It is effective against most pathogens. The maximum usage is 0.1%. Lower levels are needed at lower pH's.
Sodium benzoate and benzoic acid are very pH sensitive and will only be effective with a pH less than 4.5. The lower the pH the more effective the preservation. Optimum function is at a pH of 2.5 to a pH of 4.0.
Neither Sodium Benzoate or Benzoic Acid is 'cidal' at the levels used in baking. High levels of contamination or mold spores or contamination by resistant mold spores will not not benefit from the addition of propionates. The most important first step in reducing mold growth is proper sanitation of the plant and equipment.
Potassium Sorbate and Sorbic Acid
Sorbic acid is the compound with anti microbial properties. Potassium sorbate is more soluble in water than sorbic acid. Potassium sorbate is one of the most common preservatives used.
It is effective up to a pH of 6.5, but it is more effective at lower pH levels.
Potassium Sorbates are effective against yeast, molds and some bacteria. It is typically used in cheeses, cakes, pies, icings, beverages, dressings, candies,vegetables and other items. Usage is typically less than 0.1%. Sorbates should not be used in yeast raised items such as bread and rolls due to its action on the yeast.
Sorbates will raise the pH of the food slightly and the foods pH may need to be adjusted. Neither potassium sorbate or sorbic acid is 'cidal' at the levels used in baking. High levels of contamination or mold spores or contamination by resistant mold spores will not not benefit from the addition of propionates. The most important first step in reducing mold growth is proper sanitation of the plant and equipment.
Methyl and Propyl Parabens
Methyl paraben and propyl parabens are effective against yeast and molds at higher pH levels. They are not very soluble in water at room temperature and need to be heated to get them into solution. Methyl paraben is more soluble but is less effective at preservation than propyl paraben. They are typically used as a blend of 2 parts methyl paraben and 1 part propyl paraben. Typical usage levels of parabens are less than 0.1%.
Methyl paraben and propyl parabens are effective from a pH of 3 up to a pH of 8 and are stable to high temperatures. Methyl paraben and propyl paraben blends are the preservative of choice for pH's above 5.0.
Parabens can be used in cake items, beverages, flavors, fruit fillings, meat, syrups, dressings, jams, jellies, and wines. Do not use parabens in yeast raised items such as bread and rolls.
Methyl paraben and propyl parabens are not common due to their high costs and stronger flavors .Neither methyl paraben nor propyl paraben is 'cidal' at the levels used in baking. High levels of contamination or mold spores or contamination by resistant mold spores will not not benefit from the addition of propionates. The most important first step in reducing mold growth is proper sanitation of the plant and equipment.
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