[AIB Food Safety] Strengthening the Food Transport Chain

The scene is common. An inquisitive child reaches for a shiny object lying in the sand at the park, but before he can grab it his mom says, “Don’t touch that! You don’t know where it’s been!” It’s impossible to know where everything has been throughout its existence, which is why caution and proper sanitation are so important in the food industry.

One of the most overlooked and neglected areas in food processing is the transport that carries ingredients and finished products to and from the facility. Is it because receiving personnel are too trusting or have they not been educated about the issues related to transportation and trained to inspect the carriers for potential concerns? Can we ever really know what’s been in that transport?

There are two basic types of transport in the food industry: bulk transports (including hopper bottom cars) and tractor-trailers/railcars. Both transport types are used for rail and over-the-road loads.

Hopper bottom cars are used primarily to deliver raw agricultural commodities to mills, where the materials are discharged into an unloading pit and conveyed to storage elevators for cleaning and processing into edible food ingredients, such as flour. They may also be used to transport flour and other bulk commodities, which are unloaded in a sanitary manner using an unloading sled to transfer into a storage vessel, such as a silo. Hopper bottom transport used for this type of delivery is primarily via rail.

Bulk transports are used to transport dry or liquid bulk commodities, such as sugars, oils and flour. Materials are removed via pump or conveyed pneumatically into a silo or storage tank for use in the facility.

Tractor-trailers are used to ship bags, boxes and drums of ingredients and finished products over the road. Railcars also may be used for these deliveries, but are not as common as trucks.

HOPPER BOTTOM TRANSPORTS. Hopper bottom cars, particularly those used for raw agricultural commodities are not typically dedicated to a specific crop. The car may be used to transport soybeans and then haul wheat. A farmer delivering his crop to the mill will use the same car for multiple crops. The mill should expect that the transport be cleaned between commodity shipments (usually defined by when the crop is harvested) to prevent as much cross contamination as possible. No field is totally barren of volunteer crops from previous planting, so part of the milling process is to remove non-like materials, such as soybeans that are delivered with the dirty wheat.

Food defense is an additional consideration regarding transported agricultural commodities. A tarp or solid cover should be provided to protect and secure the crop and to prevent tampering with the empty transport vehicle. This cover should be intact and locked or sealed. Upon receipt, the seal numbers should be checked and verified against the shipping documentation. Also, it is important to make sure empty cars are inspected before they are filled.

There is a story passed around the peanut industry of a forklift that was found on a mill’s unloading magnet. Apparently, a hopper bottom car was being used to transport a forklift from one facility to another. When lines of communication crossed, the car was filled with raw in-shell peanuts before the forklift was unloaded. The mill found the forklift on its unloading magnet when the machine fell through the bottom of the car when it was opened to unload what was supposed to be raw peanuts.

Whether or not this story is true, it illustrates the fact that a simple pre-loading inspection of the transport would have prevented the mistake. Inspecting the interior of the vehicle before loading and after unloading also will allow personnel to identify issues such as peeling coatings, foreign material or structural damage that could allow static product accumulations and possible insect or mold development. These inspections also ensure that all of the product was removed to guarantee accuracy in the case of a recall.

Finished product commodities are more commonly transported via railcars with hopper bottoms rather than over-the-road carriers. The railcars usually are owned or leased by the company shipping the finished product commodity, and are dedicated to shipping the specific commodity provided.

The transports used to ship finished product commodities usually are sealed with a lining between the top hatches on the cars. These hatches are provided with numbered seals, which should be checked against the bill of lading upon receipt to ensure that they have not been tampered with during transport. A program that addresses missing or damaged seals should be implemented at the facility to ensure that materials at risk of being tampered with are not accepted.

Seals should be in numerical order on the hatches. The site should determine if there is a large gap between the seal numbers. If so, it could indicate that the hatch with the lowest series of numbers has not been opened and cleaned for a significant period of time. If the transport contains flour, the liner could have become damaged, which can lead to static flour accumulation and eventually mold or insect development. The hatch should be opened and examined to ensure that this type of contamination has not occurred.

Since there is not a set number of areas on transport that require a seal, the number of seals will vary by the type of car. Slides on the hopper bottoms and any other areas that provide access to the product should have seals in place.
Documentation of cleaning the hopper car should be provided as part of the shipping and receiving requirements. Documentation should include the date and type (i.e., dry vs. wet) of cleaning, as well as the company that cleaned the car (i.e., a supplier or cleaning service).

In addition, many sites also require the last three products shipped in the railcar be documented to ensure there is no potential for cross contamination from non-like materials.

BULK TRANSPORTS. Bulk transports are primarily shipped via over-the-road tanker cars. However, bulk oil and liquid sugar products most commonly are shipped by rail.

Bulk rail and over-the-road transports have similar issues. Hatches and other areas that provide access to the product should be sealed. Depending on whether a dry or liquid commodity is being transported, unloading hoses, pumps, pneumatic systems for dry unloading and strainers may be included on over-the-road transports. As with hopper bottom cars, the number of seals and areas to be sealed depends on the carrier. In addition to sealing areas that provide access to the product, unloading hoses, pumps, pneumatic unloading equipment, and strainers should be sealed to prevent tampering from occurring. These seals should also be included on the shipping documentation and verified upon receipt. Procedures that identify what should occur if a seal is missing or incorrect should be in place.

Similar to hopper bottom transports, the receiving procedures for bulk transports should include verification of seal numbers, inspection of the car before and after loading, and cleaning documentation. Documentation of the last three loads of product may also be required if cleaning does not occur between each delivery of different products.

Carriers with self-contained systems to pump material into customer silos or storage tanks will have additional inspection points to consider. For dry material transports, a pneumatic system typically is used to fluidize flour or other bulk dry commodity for off loading into the system. To prevent a vacuum from occurring during unloading, a hatch on top of the carrier is opened to allow air replacement and prevent the tanker from collapsing. A filter or means of protecting the product from contamination must be provided on hatches opened for unloading purposes. The air used to fluidize the flour or bulk material must be filtered to prevent product contamination. The unloading lines, gaskets and couplings for these systems must be inspected and must be clean and in good condition prior to unloading.

Over-the-road carriers are used to transport a wide range of products that can be more microbiologically sensitive than materials shipped in bulk rail cars. If microbiologically sensitive materials, such as milk, ice cream mix or liquid eggs are transported, dedication of the carrier, temperatures and cleaning of the car become a paramount importance. A calibrated thermometer should be used to document the temperature of these materials upon receipt. The receiving company should verify the dedicated use of the carrier and require a wash certificate for the transport vehicle.

Transports containing liquid pumps and strainers also may be inspected as part of the receiving process. Before unloading the vehicle, verify that strainers are in place, clean and intact. After material has been unloaded, the strainer should be inspected again to ensure that it is intact and that there is no foreign material. Pumps should be inspected to ensure that they are clean and that impellors are in good condition. Cracked or damaged impellors can provide a source of foreign material contamination. Gaps and cracks in pump impellors are not readily cleanable and can provide an area for microbiological development. Unloading lines, gaskets and coupling also must be inspected, and be clean and in good condition prior to unloading.

When sensitive materials are received, the wash company or site that cleaned the transports should be verified as part of the approval process. Large CIP systems are used to clean the inside of each bulk transport after delivery. If these sites are not within your control, then documented verification of the site’s cleaning system should be provided. Verification of wash systems should include temperature, flow rates and pressure of the CIP system as applicable to the process. These systems should be routinely serviced and calibrated and should include functionality of conductivity meters if they are used.

Maintenance of these systems typically is documented as part of a preventative maintenance program or as a service contract with the detergent/equipment supplier. The supplier should provide documented calibration of automatic detergent delivery systems, in addition to physical testing and verification of sanitizer concentrations and, if applicable, the pH of the rinse water to ensure that all sanitizer was adequately removed. Documentation proving that detergents and sanitizers are approved for food contact surfaces and that potable water is used for cleaning and rinsing also should be available. Calibration of charts used to record such things as temperatures and conductivity should not be overlooked as part of these programs. The condition and cleanliness of pumps and impellors cannot be ignored.

TRACTOR-TRAILERS. Tractor-trailers are widely recognized by food companies and consumers. Tractor-trailers or railcars are sometimes described as “warehouses on wheels” by corporate sanitarians. They come in three basic types: refrigerated, frozen and dry. There are very few food companies that maintain their own dedicated fleets of carriers. Most of the industry uses common carriers or contracts carrier companies to transport their goods. Agreements with common carriers or lease companies that transport food must stipulate that these trailers are never used for transport of non-food items such as chemicals, plants, medical waste, garbage or any other material that could contaminate the food product transported in them. Inspection of the vehicle before loading and during off-loading should identify any unusual findings. If contamination or a potential contamination issue is identified the material should be rejected. With less-than-load (LTL) carriers, personnel should also examine the other materials that are contained on the carrier during off loading to ensure that food materials are not shipped with chemicals or other materials that could lead to product contamination. 

Temperatures of materials must be defined and verified when refrigerated and frozen transports are received. It is a common practice to use a calibrated thermometer to verify temperatures from the front, middle and back of each load received. Haulers that transport temperature-sensitive materials may use a reusable recording device that has a certificate of calibration to take the temperature and then download the information to verify the products’ temperature history throughout transport. To ensure that the cold chain for refrigerated and frozen products is maintained, trailers should be pre-cooled before loading and this activity should be documented. Unanticipated problems occur every day. Procedures should be developed and implemented in case a transportation problem occurs (i.e. a reefer fails or delivery is delayed due to an accident) in order to ensure that the product is handled safely and properly.

An inspection of the trailer’s condition should be required. Floors, walls and ceilings should be clean and in good condition to prevent contamination of the transported materials. Holes in the floor or roof should be repaired before materials are loaded to prevent product contamination from roof leaks, road debris, or insects and pests that could enter the carrier. Doors and door gaskets should be intact and sealed properly.

As with bulk transports, trailers should be sealed to prevent product tampering. It is a common practice to require full-load trailers to be sealed and verified and included in the shipping documentation. LTLs pose a unique challenge and may be managed differently. In some cases, the driver is provided with seals that can be cut and replaced for each delivery stop. In other cases, a padlock is provided and the driver is able to unlock and relock the trailer after each delivery. In other cases, shrouds tamper-evident tape or other tamper-evident seals are provided on the product to indicate if the material has been tampered with. The risk to product and the type of product transported should be considered when evaluating how LTL transports are handled. It is impossible for drivers to remain with the load at all times throughout transport. They must sleep, eat and take restroom breaks, so the load will be unattended at times.

CONCLUSION. No matter what type of transport is used to ship your raw materials or finished products, maintaining product safety, quality, and food defense is the goal. Knowledge, procedures, training and proper handling of these transports and the issues that may arise will ensure a safe and wholesome food product is delivered to consumers and their families.

The author is Field Operations Director at AIB International.