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Tobacco flakes on cigarette filters grow bacteria: a potential health risk to the smoker?
  1. J L Pauly,
  2. J D Waight,
  3. G M Paszkiewicz
  1. Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
  1. Dr John L Pauly, Department of Immunology, Cancer Cell Center, Room CCC-307, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA; john.pauly{at}


Bacterial growth from a single flake of tobacco was documented for cigarettes that had been purchased recently from local vendors and from cigarettes that had been stored for more than six years in a warehouse. In a novel tobacco flake assay, a pack of cigarettes was opened within the sterile environment of a laminar flow hood. A single flake of tobacco was collected randomly and aseptically from the middle of the cigarette column and placed onto the surface of a blood agar plate. The test cigarettes included eight different popular US brands, and these were from three different tobacco companies. After 24 hours of incubation at 37°C, the plates showed bacterial growth for tobacco from all brands of cigarettes. Further, more than 90% of the individual tobacco flakes of a given brand grew bacteria. Likewise, bacteria grew from microparticulate tobacco that had been sieved from cigarettes. Tobacco flakes were observed lying loosely on the cut surface of the filter of cigarettes in newly opened packs, and bacteria grew from cigarette filters that had been touched to the surface of a blood agar plate. In conclusion, the results of these studies predict that diverse microbes and microbial toxins are carried by tobacco microparticulates that are released from the cigarette during smoking, and carried into mainstream smoke that is sucked deep into the lung.

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  • Funding: This work was supported by NIH CCSG Sub Award 5P30CA01605631 and a Clinical Innovator Award of the Flight Attendant Medical Research Institute.

  • Competing interests: JLP has served as an expert witness in court cases against the tobacco industry for which he received monetary compensation. JDW and GMP have no competing interests to declare.