mhyche

Hi, I just wanted to add a little clarity to the definitions here. I actually manufacture food for a living and am amazed by the misperception of the particulars of common food processing and packaging techniques by consumers (no offense intended). 1. Aseptic packaging refers to both a processing and packaging approach that have to go hand in hand to yield the intended results. The food product, be it juice, yogurt, baby food puree, etc., is heated to whatever temperature is required to sterilize, cooled, and then filled into a package that has been sterilized (typically with peroxide) within the confines of a packaging machine that is assumed to be sterile or "aseptic" before the package is hermetically sealed. Aseptic presumes the combination of a highly sophisticated packaging system that can maintain sterile conditions and a controlled process that can heat the product to the appropriate temperature. Aseptic products are always liquid as the heating is done in pipes that transport the product to the packaging machine. There are few if any aseptic processes that are approved by the FDA that have any particles in the product as the heat transfer is very difficult to validate in the heat exchange system. 2. Canned or Retort processing refers to the sterilization of the food product after it has been sealed in the package. This process was invented many years ago and for most foods that are in cans (so called "low acid foods") the temperature required to sterilize the food is around 250F. If the food is somewhat acidic, the sterilization temperatures can be lower. 250F is a magic number in that it is the temperature required to kill bacteria from Genus Clostridium (Clostridium Botulinum is the most famous). These bugs don't ever pose a problem in fresh foods because they cannot grow in the presence of oxygen (or high acid for that matter). When you put food in a can, however, the food product hasn't necessarily been heated to sterilization temp, the package is not sterile, and most importantly when you seal the package, oxygenation of the food is impossible allowing Clostridium to grow if not subsequently sterilized. Here's the important part, everyone is familiar with metal cans, but this is the same sterilization process that is used with the plastic pouches and trays that are more prevalent in the market today i.e. pouch tuna, Uncle Ben's ready rice, dinty moore in the white tub, fresh mixers in the tub, etc, etc. These are not "aseptic" products. Preservatives are NOT required in either of these methods of processing/packaging - another common misconception. Preservatives are widely used though in sauces, condiments, and a lot of other products on the shelf. Most of these products have a high enough salt concentration or low enough pH (high acid) to prevent the growth of Clostridium, but not necessarily high enough to prevent the growth of other organisms. Many condiments are not heat treated at all and are filled in to their packages "cold" - so called "cold fill" packaging. Aseptic and canning are highly regulated processes by the FDA and USDA as the results of improper processing can be deadly. Each of the methods to preserve food - moisture level, salt, acid, heat, irradiation, temperature, are a "hurdle" for microorganisms to overcome in order to grow. Depending on the nature of the product vis a vis these properties, producers have to develop processes and packages to enable the highest quality food (least adulterated) with control of organism growth. Hope this helps clarify this thread a little (or maybe complicates more)