They are obligate anaerobes capable of producing endospores. "Clostridium botulinum" is a large anaerobic Gram-positive bacillus that forms subterminal endospores. Infants can develop botulism after consuming honey contaminated with "Clostridium botulinum" endospores. Nitrite inhibits the germination of endospores of "C. botulinum". The bacteria are acidophilic, thermophilic, and produce endospores. Many Firmicutes produce endospores, which are resistant to desiccation and can survive extreme conditions. Disinfection is less effective than sterilization because it does not kill bacterial endospores. This problem is compounded when food is then improperly refrigerated, allowing the endospores to germinate. "Brucella" species are small, Gram-negative, facultative coccobacilli, most lacking a capsule, endospores, or native plasmids. The powder found in contaminated postal letters was composed of extracellular anthrax endospores. Introduction of the bacteria may also occur via endospores in a wound. Perhaps the best known bacterial adaptation to stress is the formation of endospores. As a surface disinfectant MMPP exhibits a broad spectrum biocidal effect including inactivation of endospores. Small acid-soluble proteins (SASPs) are found in endospores. The main types within the cell are terminal, subterminal, and centrally placed endospores.