Asbestos Fibers in Sake

Our plain-English summary of Asbestos Fibers in Sake, by S. Ogino, N. Fukumori, T. Yasuno, et al (Journal of Food Protection, 1988).

The study

• Authors: S. Ogino, N. Fukumori, T. Yasuno, M. Koseki, M. Kazama
• Journal: Journal of Food Protection
• Published: 1988;51(9):737-739
• Read it: PubMed · Publisher

Abstract

Asbestos filters have been widely used to clear beverages in many countries including Japan, and despite warnings from the authorities, some Japanese sake companies have continued using such filters until recently. Forty-seven Japanese sake samples were analyzed using a transmission electron microscope to detect contamination with asbestos fibers. The concentrations of fibers found in sake samples ranged from <7.8 × 103 fibers/L (the detection limit) to 1.96 × 108 fibers/L. Ten sake manufacturers provided information as to whether they had used asbestos in the filtration process and the remaining 37 did not (unknown group). Five out of the 10 manufacturers from which information was available had used asbestos (with asbestos group), and the other 5 had not (without asbestos group). The concentrations of fibers in the samples of the "with asbestos" group were more than 7.7 × 106 fibers/L while those in the "without asbestos" group did not exceed 2.8 × 105 fibers/L. The concentrations of fibers in the samples of the "unknown group" ranged from below the detection limits to 1.46 × 108 fibers/L. Some brands of sake showed extremely high concentrations of asbestos fibers, and therefore it may be necessary to investigate the fate of ingested asbestos in the body and its possible carcinogenicity.

In plain English

This laboratory study looked for asbestos fibers in Japanese sake. The authors bought 47 brands at random between 1983 and 1985, filtered one liter of each, and examined a small prepared portion of what the filter caught under a transmission electron microscope, looking for chrysotile, which they said is mainly used to filter sake. Fiber levels ranged from below the detection limit (7.8 × 10³ fibers per liter) to 1.96 × 10⁸ fibers per liter. Ten makers said whether they had filtered with asbestos. Sake from the five that had ranged from 7.78 × 10⁶ to 1.96 × 10⁸ fibers per liter. In sake from the five that had not, levels did not exceed 2.8 × 10⁵. Among the 37 sakes with no information, five exceeded 1.0 × 10⁶, and the authors concluded these may have been made with asbestos. Fibers were also found in the distilled-water control, which the authors said showed possible contamination during sample preparation. They said the health risk was difficult to estimate and proposed further study of what happens to swallowed asbestos and whether it can cause cancer.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory survey measuring asbestos fibers in commercial sake samples by transmission electron microscopy, with elemental (EDX) analysis to confirm unclear fibers
• Who was studied: 47 brands of Japanese sake bought at random between 1983 and 1985 and analyzed in Tokyo, with filtered distilled water as a control. Ten makers gave information on asbestos use; for the other 37 samples it was unknown.
• Exposure: Chrysotile asbestos fibers from asbestos used as a filter aid in sake filtration, measured as fibers per liter of sake
• Main results:
  • Across all 47 sake samples, fiber concentrations ranged from below the detection limit of 7.8 × 10³ fibers per liter to 1.96 × 10⁸ fibers per liter
  • In the 5 samples from makers who said they used asbestos, concentrations ranged from 7.78 × 10⁶ to 1.96 × 10⁸ fibers per liter
  • In the 5 samples from makers who said they did not use asbestos, concentrations did not exceed 2.8 × 10⁵ fibers per liter
  • In the 37 samples where asbestos use was unknown, concentrations ranged from below the detection limit to 1.46 × 10⁸ fibers per liter
  • In the unknown group, 5 samples exceeded 1.0 × 10⁶ fibers per liter, and the authors concluded these 5 may have been produced with asbestos
  • Asbestos fibers were also found in the distilled-water control sample
  • All fibers found were less than 0.1 micrometer in diameter and most were shorter than 5 micrometers; about 70% of the fibers were shorter than 1 micrometer
• The authors' conclusion: The authors concluded that asbestos levels in some sake brands were so high that further study of what happens to ingested asbestos in the body, and of its possible ability to cause cancer, was proposed
• Limitations the authors state:
  • Clumps of tangled fibers in asbestos-rich samples were excluded from counting, so the reported concentrations may be underestimated
  • Fibers in the distilled-water control showed that contamination may have occurred during sample preparation
  • The authors stated it was difficult to estimate the human health risk from drinking asbestos-contaminated sake

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