Tip of the Week: Stopping Hidden Danger In Its Tracks: Prevention Series

We're wrapping up our Hidden Dangers: Prevention series this week by turning our attention to flour mills. Each product segment in the food industry faces unique risks and hazards related to the processes and equipment they use. We're highlighting some segment-specific hidden dangers and recommending prevention measures to stop them in their tracks. 

Hidden Danger: There are several areas in the flour milling process where moisture can generate mold growth and provide an area for insect development. Higher moisture areas may also provide an environment for Salmonella and pathogenic E. coli. Areas where this may occur are in elevator bins and flour bins where temperature differentials between the bin itself and the outside air temperature allows water to condense in the headspace of the bin. This combined with the grain or flour dust provides an environment for mold growth and insect development, such as flat grain beetles or psocids. 

Water that is added to wheat at the Technovator/mixer and fed into the tempering bins also provides an environment for mold development. The milling process itself creates conditions, such as at first break, where the release of moisture from the tempered wheat going through the first grinding process allows moisture from the product to be released, providing an opportunity for mold growth and development.  

Mold can also be an issue in milling equipment located by a window where the temper differential caused by the equipment’s location next to the window, allows condensate to form creating an environment for mold development. Condensate issues due to temperature variations are often a result of large temperature changes that occur due to a change in seasons. 

Solution: There are several approaches used to identify, reduce, and control moisture within the milling environment. Where temperature differentials exist between a vessel, such as a flour bin, and ambient air temperature, air dryers may be installed to help reduce moisture in the air that is used to convey product. Air balance in the mill is not only key to the quality of the flour produced, but also assists in moisture reduction in the process to help eliminate condensation within equipment or product streams.

Examination of bin bottom samples in the elevator and tailings in the mill for evidence and identification of insect species may also help identify mold issues within bins or other vessels. Flat grain beetles, hairy fungus beetles, and foreign grain beetles favor higher moisture conditions. After insect identification, tracing the origin of the flour or grain to the storage vessel may aid in identification of a mold or moisture issue with the product or within the equipment. 

Chlorination of the water added to the wheat as part of the tempering process may also help in reducing potential for mold development as part of the tempering process. Periodic dismantling, cleaning, and sanitizing of the mixers/technovators and associated equipment will assist in elimination of wet product residues that could allow mold development. Vented or screen handholds that allow moisture to escape the spouting at the knees of the sifters and purifier discharges allow moisture to escape and help reduce mold development.

Hidden Danger: Stored product insect development is a hazard where either flour or grain has a place to stagnate. Look for insects in dead ends, dead boxes, the base (boot) of elevator legs, or equipment that has been taken out of service but not removed from elevators, the cleaning house or the mill.

Solution: There are two different approaches to identifying how to prevent stored product insects infestations in mills. Eliminating stagnated grain or flour buildup in equipment is one approach. First, the flour or grain must be removed on a frequency to break the insect reproductive life cycle. The second, is that easy access to the areas where product stagnation occurs must be provided to allow this to happen. Slide gates are provided as access to the boot of the elevator to allow easy access for removal of any grain or flour residues to ensure that infestations do not develop. Cleaning frequencies of no more than 30 days help ensure that these residues are removed often enough to break the insect life cycle. Design of self-purging dead boxes or appropriately designed access to the bottom of the dead box coupled with an appropriate cleaning schedule will also help prevent insect development. As always, when equipment is no longer needed, the best solution is to remove it so that it does not provide an area for product collection and subsequently insect development or harborage. Where it is not practical or possible to remove the equipment due to size or location, then dismantle it as much as possible to allow easy access. Maintain it on the master cleaning schedule, and examine it as part of the self-inspection program to help identify and prevent stored product insect development. 

Hidden Danger: Control of containers and utensils when dealing with a process that takes a raw agricultural commodity and transforms it into a finished product that becomes a food ingredient. A common pitfall identified during inspections is using the same brush that is used to clean the floor or equipment exterior to then clean inside the product zone, or using a container identified for edible use for non-edible purposes. 

Solution:  An identification system (e.g., labeling or a color-code system) is the first step in ensuring that there is separation between tools, utensils, or containers that are to be used for food contact\edible or non-food contact\non-edible purposes. Establishing this system and providing training aids, posters, or signs in strategically placed areas will help reinforce the training against the defined system and will assist employees in using the right tool or container for its intended purpose. 

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