Somebody told me if sugar has an expiration date. In this post I wanna talk about the importance of some parameters in food safety and particularly about water activity. In food safety the main parameters we use to project any food and to see if they are shelf stable are: water activity, temperature, pH. Water activity is defined as the vapor pressure of water above a system divided by that of pure water at the same temperature. Distilled water has a water activity value of 1 and a pure fat system of zero. Simply speaking the water activity is a measure of "free" or "available" water in a system, since the presence of dissolved species makes an interaction between them and the water through hydrogen bonding, dipole-dipole attraction or ionic bonds. A measure of water activity will help us in predicting if the growth of mold or a microbiological contamination can happen. Therefore, taking into consideration that the water amount in the sugar we can have at home is less than 0,3 % and that chemically speaking sugar has a cristalline structure, it is hard can be contaminated if it is well stored. In fact it is used in food industry as preservative in several food formulations. If you keep it in a closed can, at room temperature, the sugar can be kept indefinitely. Dont worry about it...sugar sugar...honey...honey!!
Monday, July 20, 2009
Sugar...sugar...honey...honey!
Somebody told me if sugar has an expiration date. In this post I wanna talk about the importance of some parameters in food safety and particularly about water activity. In food safety the main parameters we use to project any food and to see if they are shelf stable are: water activity, temperature, pH. Water activity is defined as the vapor pressure of water above a system divided by that of pure water at the same temperature. Distilled water has a water activity value of 1 and a pure fat system of zero. Simply speaking the water activity is a measure of "free" or "available" water in a system, since the presence of dissolved species makes an interaction between them and the water through hydrogen bonding, dipole-dipole attraction or ionic bonds. A measure of water activity will help us in predicting if the growth of mold or a microbiological contamination can happen. Therefore, taking into consideration that the water amount in the sugar we can have at home is less than 0,3 % and that chemically speaking sugar has a cristalline structure, it is hard can be contaminated if it is well stored. In fact it is used in food industry as preservative in several food formulations. If you keep it in a closed can, at room temperature, the sugar can be kept indefinitely. Dont worry about it...sugar sugar...honey...honey!!
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