Influence of transition metals added during sporulation on heat resistance of Clostridium botulinum 113B spores

Abstract

Sporulation of Clostridium botulinum 113B in a complex medium supplemented with certain transition metals (Fe, Mn, Cu, or Zn) at 0.01 to 1.0 mM gave spores that were increased two to sevenfold in their contents of the added metals. The contents of calcium, magnesium, and other metals in the purified spores were relatively unchanged. Inclusion of sodium citrate (3 g/liter) in the medium enhanced metal accumulation and gave consistency in the transition metal contents of independent spore crops. In citrate-supplemented media, C. botulinum formed spores with very high contents of Zn (-1% of the dry weight). Spores containing an increased content of Fe (0.1 to 0.2%) were more susceptible to thermal killing than were native spores or spores containing increased Zn or Mn. The spores formed with added Fe or Cu also appeared less able to repair heat-induced injuries than the spores with added Mn or Zn. Fe-increased spores appeared to germinate and outgrow at a higher frequency than did native and Mn-increased spores. This study shows that C. botulinum spores can be sensitized to increased thermal destruction by incorporation of Fe in the spores.

Sensitivities to Hydrogen Peroxide Vapor of Intact and Decoated Spores of Bacillus subtilis As Influenced by Divalent Cations Supplemented in Sporulation Medium.

“…The Fe" content was relatively low even in Fe-supplemented spores themselves and, instead, Ca" was a major constituent. These findings concur with previous results of other researchers (Kihm et al, 1990 ;Marquis and Shin, 1994) . As compared with that in the spores of strain 168, the Mn" content in Mn-supplemented spores of strain ATCC9372 was relatively low.…”

“…It remains unclear why and how the mineralization affects the spore resistance in the solution phase and in the vapor phase differently. One possible factor may be a specifi scavenging action of intrasporal Mn2+ against hydroxyl radicals generated from hydrogen peroxide (Kihm et al, 1990). This action of Mn2+ might be marked in dehydrated spores rather than hydrated spores.…”

Incidence of Clostridium botulinum Spores in Honey and Infant Food Samples Collected from Vietnam and Germany

“…The detailed effect of SSS on sporulation and toxigenicity of C. botulinum spores was not reported in previous studies. Kihm et al (1990) found that C. botulinum 113B sporulated well in media containing 0.01 to 1.0 mM Fe, Cu, Mn, or Zn.…”