Agronomic foods often are naturally contaminated with harmless and pathogenic microorganisms. In most cases, agronomic goods are fresh-processed, or appropriately processed to preserve and increase shelf stability. Common preservation techniques include heat pasteurization or sterilization, irradiation, desinfestation with gaseous substances etc. In particular, the two latter techniques are rarely used nowadays due to legal restrictions as well as safety and nutritional concerns.
In 2001 and 2004, incidents of salmonella infections caused by raw almond consumption were reported in the US and in Canada. In order to secure and improve the safety of almond consumption, the USDA has enacted a rule that all almonds used in domestic markets have to be treated with a process realizing a 4 log reduction of the corresponding salmonella species (USDA, 2007). This rule is set active from September 1, 2007 and affects the complete Californian almond harvest dedicated to the markets in the US, Mexico and Canada.
Because almonds as well as tree nuts and other seeds are susceptible to quality changes during processing, the safe inactivation of salmonella requires new pasteurization techniques able to preserve the original quality. In particular, the moisture content of raw almonds must not increase relevantly during or after the treatment reducing shelf stability and impairing appearance. In addition, almonds tend to lose their brown skins if treated in humid atmosphere impairing quality massively. In case of treatment with moist heat, the modification of flavors, such as the generation of cooked flavor notes and typically generate a “cooked” or “boiled” note in the almond – this has to be avoided as well.
The “Controlled Pasteurization Process” pasteurization system (CPP) is is a nut pasteurizer for (in-shell, raw & salted/roasted) tree nuts, peanuts, as well as seeds, herbs and spices. The system can be installed in line with existing (continuous belt) roasters.
The revolutionary NR-IPP roaster incorporates Integrated Pasteurization Processing (IPP) technology – raw nuts enter the roaster and are discharged roasted and pasteurized. Important to note is that the pasteurization is completely independent from the roasting degree; even with very light, low temperature, short roasts, a minimal 5 log reduction is guaranteed.