Bagged Ingredient Storage
November 01, 1996
by Teresa Acklin
Guidelines help feed manufacturers assure proper design of ingredient storage and handling facilities.
By Joseph P. Harner III and Fred Fairchild
Feed manufacturers often handle microingredients in bagged form. Ingredients such as dicalcium phosphate or calcium may be handled in bagged or bulk form depending on the quantity of feed produced per year, and feed manufacturers who use mobile grinders-mixers generally purchase their microingredients as base or premix in bagged form.
Ingredients are purchased proportional to bags of ingredients per tonne of feed per ration, so different bag sizes generally are involved. In some rations, the bags may need to be 20 kilograms, whereas another ration may require bag ingredients to be in 25-kg bags.
Good Manufacturing Practices (GMPs) in many countries specify that adequate procedures be followed for storage and handling of bagged ingredients. Under GMPs, procedures are needed for identification; storage; and inventory control, including receipt and use of medicated articles and medicated feeds. GMPs also require that bagged ingredients are stored in their original, closed containers and that storage practices assure the identity, strength, quality and purity of these drug sources.
Bags are often stored in older buildings or machinery sheds. Occasionally, even discarded trucks or vans are used for storing bagged ingredients. These types of storage facilities also often are used for storing nonfeed items, and they seldom are rodent- or bird-proof.
GMPs require bagged ingredients to be stored in buildings that are rodent- and bird-proof, with no storage of petroleum-based products or other products, such as batteries, within the bagged storage area. Multipurpose buildings also do not lend themselves to maintaining feed production records or provide an environment for maintaining scale accuracy.
Figure 1 shows a single purpose building for storing bagged ingredients. The building width is limited to 6 meters, which provides access to all ingredients; the building length can be adjusted depending on the storage required for the bagged ingredients.
Most standard pallets require a storage space of 1.2 meters by 1.2 meters. In this design, ingredients can be stored along the exterior walls while maintaining a 2.5-meter walkway between the bags.
Ingredients are unloaded into the building at the unloading dock at the end of the building. A 60-centimeter walkway is allowed between pallets and walls for access and rodent control.
A fence is used to prevent incoming trucks from carrying diseases into the production area. The building should be located near the feed center where grain and meals are stored, but also such that delivery trucks do not have to drive through the production area.
A small office and restroom are included in the plan shown in Figure 1. The office is for maintaining records of ingredient usage, in particular medicated feeds. The restroom provides an immediate area for worker protection and washing after cleaning a mixer. An area, preferably inside the building, should be designated for containing empty bags awaiting proper disposal.
The exterior concrete slab in Figure 1 has two main purposes. The first is for loading the mixer and cleaning up any spills created while filling. The second purpose is for cleaning the mixer and removing residues. The mixer's trap doors can be opened to allow any residues to spill onto the concrete slab, which can be easily cleaned.
The building should have a concrete floor. Windows must be covered with 0.33-cm wire mesh screens, and doors should seal such that perimeter openings are less than 0.33 cm.
It is important to construct the building to provide for expansion yet not so large that additional space is consumed by nonfeed items. The exterior around the building should be void of vegetation (grass, trees, shrubs) for a minimum of 60 cm out from the walls.
The building can be insulated and heated, with insulation installed below the roof to minimize moisture condensation problems. Because insulation often provides a place for rodents to live, precautions should be taken during construction to prevent rodent entry into insulated walls.
Standard pallets often require manual labor during handling and utilize more space than available. Some feed producers instead use mini pallets, which measure 30 by 60 cm or 38 by 60 cm.
These wooden or plastic pallets can hold about 270 kg of material by stacking ten to twelve 23-kg bags. These pallets offer the advantage of less storage space required for bagged ingredients, maintenance of a fresher supply of ingredients or more frequent stock rotation. Plastic mini pallets can be recycled, and labor required to handle bags is reduced.
But mini pallets cannot be stacked on top of each other and are limited to "one" high stacking. Fork lifts are not as efficient when handling mini pallets as standard pallets.
Figure 2 on page 33 shows a floor plan of an existing workshop or machine building that has been remodeled to include a feed storage room for storage of mini pallets and weighing of base ingredients. For storage inside an existing machinery building, mini pallets are recommended because the 60-cm space around the perimeter of the walls for rodent control can be maintained.
A counter along one end of the wall can be used for record maintenance. The area beneath the counter should be open to provide space for clearly marked containers that are used to store open bags or medicated feeds from a mixer.
Larger feed processing centers also need adequate facilities for storing bagged microingredients. More floor space generally is needed for storing bags because each individual ingredient, such as the different vitamins, is handled in bagged form.
The same storage principles apply to large feed manufacturers as previously discussed. Bags should be stored near the weighing or proportioning center to minimize handling. A larger unloading dock for semitrailers may be required for mills handling bags.
For feed manufacturers of any size, there are four common problems with bag storage areas: rotation of stocks, excessive moisture, torn bags and rodent control.
Often, bags placed near an exterior wall are not used unless a shipment is delayed or supplies are running low. When a new shipment of bagged ingredients is scheduled to arrive, the on-site ingredients need to remain separated and used first. This may require two separate storage areas, or moving existing ingredients and placing the new ingredients to the rear.
Excessive moisture causes the product to set up or cake in the bags. Bags that are not used within a week should be placed in clearly marked containers, such as a plastic trash can, which limit moisture access.
Problems with torn bags often occur during unloading and handling. This can best be prevented through proper bag handling and good management techniques.
Rodents can be controlled through proper housekeeping and sanitation practices. Leaving a 60-cm walkway between the bags or pallets and the wall helps by allowing accessibility to the area for rodent control practices. Cleanliness outside the room and inside and outside the building also is an important step in rodent control.
This article is based on a paper by Joseph P. Harner III, biological and agricultural engineering, Kansas State University, Manhattan, Kansas, U.S.; and Fred Fairchild, feed manufacturing, Kansas State.