According to a press release issued by a leading multinational producer of vitamins and premixes, residues of chloramphenicol, an antibiotic, were found in a competitor’s premix prepared in Germany from raw materials sourced presumably from Asia.

Chloramphenicol is a broad spectrum antibiotic with intracellular proteolytic activity, which makes it extremely effective against both Gram positive and negative bacteria. For many years the compound has been confined to topical therapy in industrial nations. Chloramphenicol is responsible for bone marrow toxicity resulting in aplastic anemia. The compound can also induce sensitivity in patients, especially those concurrently receiving other antibiotics or drugs.

Chloramphenicol has also been associated with leukemia and adverse effects in neonates. Based on the risks associated with the compound and the fact that activity has been superseded by less toxic and more effective compounds use of the compound is strictly controlled with outright bans on administration to livestock in many nations.

Cross contamination   

Unfortunately chloramphenicol is freely available in Asia and is extensively used and abused for both livestock and in aquaculture. The fact that large quantities of the drug are manufactured and transported creates the possibility of cross contamination with less toxic drugs and nutrients. In the present case it is evident that ingredients incorporated in premixes were contaminated with chloramphenicol at some stage in the chain extending from production through delivery.


Risks of incorporating a toxin, such as a banned antibiotic, PCB or dioxins in a premix are self-evident. In the case cited, 38 tons of contaminated pre-mix were destroyed. If the pre-mix were to be incorporated at the rate of 2 lbs. per ton in layer feed, it would be sufficient to supply 1 million hens with contaminated feed for 12 weeks. The same quantity of 38,000 tons of contaminated feed would supply a 1 million bird per week broiler operation for 7 weeks. The financial impact of traceback, recall and destruction of product subjected to contamination by an illegal additive are immense.

Ensuring purity  

Manufacturers of premixes should therefore apply commensurate care in sourcing ingredients from reputable manufacturers and to maintain acceptable state-of-the-art analytical procedures to ensure purity. It is known that one company in the U.S. manufacturing a range of yeast-based mineral proteinates rejects up to 50% of shipments of copper, manganese, selenium and iron based on contamination with heavy metals. A second U.S. company manufacturing a range of xanthophyll pigmenters assays for dioxins, PCBs and PBBs in imported oleoresin derived from marigold petals. Both these companies have invested heavily in highly sophisticated analytical spectroscopy to ensure the purity of their products.

To ignore the realities of contamination is to invite disaster. Regulatory intervention, recalls and public rejection of products represent the negative side of an equation in which suppliers of premixes consider only expediency and cost of raw materials and neglect quality assurance.