Focus on Food Safety: Processes and Ingredients – Part III

Heating — Cooking to an internal temperature of 165°F or 74°C or more for at least four minutes kills most bacteria in and on a food product. Unfortunately, most foods cannot be packaged directly after cooking, and most undergo further processing and packaging after cooling or freezing, exposing them to post-cooking contamination. However, pasteurizing the product by applying intense heat for a short time to the surface of the product just prior to or just after packaging effectively reduces bacterial counts and slows subsequent growth. This can be done with steam, electrical conductive (ohmic) heating, infrared light, emersion water baths and continuous oil-emersion fryers for pasteurizing foods both pre- and post-packaging.

pH — About the same time as our ancestors were learning to preserve foods with salt and sugar, they discovered that foods could also be preserved in sour wine otherwise known as vinegar. Pickling, as this process is called, reduces the pH of food to about 3.5 on a zero to 14 scale, producing an environment most bacteria do not tolerate well. Salt and spices frequently used in pickling processes make bacterial living conditions much harsher. Vinegar, or acetic acid, is also the starting material for other chemicals that help make our foods safer. For instance, it acts as a pH buffer to ensure that the pH does not change quickly. In other words, it has some staying power. This buffering capacity of acetic acid improves significantly in the form of sodium, potassium or calcium salts known as acetates. Chemical names to look for include sodium, potassium and calcium acetate, and sodium diacetate.

Aseptic post-processing and packaging environments — In the not-too-distant future I believe some Canadian food processors may begin to create aseptic environments in which to handle foods. Tetra Pak introduced the world to aseptic processing over 30 years ago, and aseptic technology is embraced by larger food processors in Europe, Asia and South America. This is not so in North America simply because the best way to implement this technology is to build a new facility. Upgrading and retrofitting existing plants is expensive, and given our recessionary times, few companies are prepared to make the investment and take the chance that consumers will reward them for it. Still, I’m confident in predicting that one or more Canadian food processors will adopt aseptic technology in the next five years. Doing so eliminates the need for some, if not all, of the chemical and processing intervention options.