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Feasibility of Milling Gluten-Free Flours . Jane DeMarchi North American Millers’ Association August 19, 2005. North American Millers’ Association. 96% of the US milling capacity for the wheat, corn and oat milling industry More than 160 million pounds daily 48 corporate members
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Feasibility of Milling Gluten-Free Flours Jane DeMarchi North American Millers’ Association August 19, 2005
North American Millers’ Association • 96% of the US milling capacity for the wheat, corn and oat milling industry • More than 160 million pounds daily • 48 corporate members • Supply products to bakers, cereal makers, packaged food companies, brewers, and directly to retail
Cross Contact Begins at the Farm • Producers often rotate wheat, barley, rye and oats on same land - volunteer plants in subsequent years • Several crops may be grown in close proximity on one farm • Great variability from year to year due to weather, etc. • Farms use the same harvesting, transport, and storage equipment without significant clean out • Some corn and oats are purchased on a contract basis for greater control but mixture is not eliminated in these cases
Grain Storage & Transportation • Trucks and rail cars used to transport grain are another source of cross contact • Grain elevators do not thoroughly clean out silos or equipment when switching grains - in part to minimize dust for health and safety • Elevators have basic equipment to clean grain but not specifically to separate mixed grain
Grain Specifications Allow Other Grains • Grain specifications are based on the US Grain Standards • Oats • Typically contain 0.5-1.0% cereal grain admix • Maximum of 2-3% allowed depending on the grade • Corn • 2-4% broken corn and “foreign” material depending on the grade • Milling quality specifications may be more restrictive
The Milling Process • Grain “cleaned” prior to milling • Width grading - sieves • Length grading - rotating drums • Density separation - gravity tables • Grains that are very different in size and shape (such as wheat and corn) are easier to separate than like-sized grains
Deficiencies of Cleaning Technology • Length, width and weight of kernels of different grain can be similar in many circumstances Barley Oats Rye Wheat
New Technology • Color or optical sorting machines • Expensive • Low capacity • Not reliable - if color differences are small
Internal Cleaning Procedures • Good Manufacturing Practices • Mill equipment is regularly cleaned and inspected. It is critically important to a mill that product dust not be allowed to gather. • Internal cleaning is dry cleaning, vacuum and wipe out • Special procedures are used for changing grains. • HACCP includes analysis of allergen risk.
Testing • Corn and wheat mills generally do not conduct tests for cross contamination on finished product. • ELISA tests are not used for cross contact of grains in mills. Granulation and small test samples cause results to vary dramatically • In an oat mill, representative samples are hand sorted and visually inspected
Economics of Grain Milling • Many mills are dedicated to a single grain or have dedicated lines • Mills operate as close to 24/7 as possible • Shut down time is minimized • Cross contact grains can not be cleaned out 100%. Mills can not lose too much of the desired grain in the separation process • Testing every bag of product is not feasible • Emphasis on prevention
Concentrations of Gluten Bearing Cereal Admix • Research has not been done to quantify the levels of cereal admix in oats or corn on an industry wide basis. • Individual customers may establish standards but so far it is not common • Variability from year to year is large
Trace Grains In Finished Products • Varies depending on product and portion size. Concentrations of wheat protein in oat flour will be higher than those in oat flakes due to the milling process. • Example: 28 gram serving of instant oatmeal • 7.5 milligrams of wheat and barley protein - approximately 40% (3 milligrams) of which would be gluten. (Assumes a .03% contamination of wheat at 15% protein and barley contamination of .16% at 14% protein content)