There has now been a period of time since the flurry of sensationalized news reports about wood pallets and their relationship with pharma recalls over the last few years, and a recently released PDA technical report has been published to provide guidance on how to detect and mitigate TBA and TCA odors and taints. Bottom line, in the increasingly global supply chain, the oft overlooked pallet can no longer be taken for granted.
As many readers will recall, some South American wood pallet material used to build pallets in Puerto Rico had been applied with a treatment (TCB) to prevent the growth of mold on pallets. The “warm, humid environment in Puerto Rico increases the probability that xerophilic fungi will grow on wood pallets converting TBP to TBA through biomethylation,” the Task Force members observed in a paper posted at pharmtech.com. While this chemical is registered for use in certain parts of the world, it is not registered in the U.S.
The Report, PDA Technical Report No. 55 (TR 55) Detection and Mitigation of 2,4,6-Tribromoanisole and 2,4,6-Trichloroanisole Taints and Odors in the Pharmaceutical and Consumer Healthcare Industries provides background on issues with TBA and TCA taints, highlighting:
- Uses of 2,4,6-tribromophenol (TBP) and 2,4,6-trichlorophenol (TCP) in industry
- Role of fungal halophenol methylation that generates TBA and TCA haloanisole taints
- Sensory and physiochemical properties of TBP, TCP, TBA and TCA
- Case examples from food and beverage industries with root causes and remedial actions
- Recent examples of TBA taint recalls from the pharmaceutical and consumer healthcare industries
Additionally, this report offers guidance on signal detection from adverse event and/or product quality complaints and resulting recalls, toxicology and safety, analytical method development and use, supply chain controls, risk analysis and mitigation. Definitions of technical terms used in this report can be found in the glossary. The principles and tools used to manage these taints are also defined in this report.
The report offers a variety of conclusions with respect to risk mitigation steps. These include:
- Not using pallets constructed from TBP treated lumber
- Controlling the moisture content of wood to levels not conducive to fungal growth
- Improving supply chain awareness of haloanisole taints
- Eliminating other sources of halophenols
- Providing adequate environmental control and ventilation in warehouses and during transportation.
It also stresses that this is not a toxicity issue, but if the smell has an adverse affect, for example, of patients taking their medication, then it is a matter of concern.
“Finally,” the Task Force paper concludes, “it is up to the pharmaceutical and consumer product manufacturer to understand their pallet supplier(s), classify them appropriately, and work with the supplier’s controls on pallet manufacturing. Companies should implement internal pallet controls to minimize risks from TBA (TCA) tainting accordingly as noted in the PDA Technical Report.”