Wheat Flour Pasteurization

Wednesday, February 11th, 2015

Problem: Ready-to-Eat (RTE) food products, such as cookie dough and raw or frozen pizzas, do not go through a factory cooking step resulting in potential microbial contamination in the flour supply chain. A growing number of consumers are eating these products without cooking them. Manufacturers needed to implement a pasteurization process prior to recipe formulation in order to minimize the risk of illness resulting from raw product consumption.

One example of this commercial requirement was:

  • Product Rates: > 20,000 kg/hr
  • APC: 14000 cfu/g Coliform: 1,850 cfu/g Mold: 645 cfu/g

Additional considerations included:

  • Maintaining raw moisture content
  • Functionality in doughs and flavor profiles
  • Systems needed to be easily integrated into a flour mill, or upstream of the manufacturer’s food pasteurization process.

Solution: The Solidaire® paddle dryer system from Bepex International was used as the heart of a complete heat treatment system to raise the flour to a temperature that allows for the pasteurization of food. The Whole Grain Bepex Stabilization system was specifically designed to process pasteurized flour while preserving most of the original flour characteristics such as moisture and functionality in the dough.

At Bepex’s Process Development Center, non-pasteurized flour was fed at a rate of 330 kg/hr and heated to above 75°C into the treatment system. The highly-efficient Solidaire Indirect Dryer provides very close contact between the material and the heating surface. This efficiency allowed for a strong, uniform kill-step with a residence time at less than 60 seconds. This pasteurization process allowed the material to be heated above the kill temperature with minimal impact on the overall characteristics.

Benefits and Results:

Final ValuesLog Reduction
APC570cfu/g1.6
Coliform< 103.2
Mold< 102.8
  • Reduced micro flour was economically produced in a simple single step process
  • This food pasteurization process can be integrated easily in most flour mills, with no added operator supervision.
  • This pasteurization method is flexible with regard to grain type and degree of milling (whole grain to extracted flour).
  • Enhanced capacity and function can be achieved by including direct steam injection.