A total of 635 specimens of foods on the market, including raw meat, processed meat and fish products and raw oysters, were examined for the presence of
C. perfringens. The heat-sensitivity and serological relationships to Hobbs' 1-17 types of the isolates were investigated.
1.
C. perfringens was isolated from 180 (47.5%) out of 379 unheated raw meat specimens, and heatresistant strains were isolated from 3 (0.8%) of these specimens.
2. After heating for 15 minutes a 80°C,
C. perfringens was isolated from 63 (16.6%) out of 379 raw meat specimens, and heat-resistant strains were isolated from 18 (4.7%) specimens.
3. Heat-resistant
C. perfringens was isolated from 36 (59.0%) out of 61 raw meat specimens of 30 gram each after heating for 30 minutes at 100°C. The heat-resistant and serotypable strains were isolated from 14 (23.0%) specimens.
4.
C. perfringens was isolated from 9.3 per cent of processed meat and fish products (20/215) by cultures of unheated specimens, and from 6.1 per cent of those (5/82) by cultures of heat-treated specimens (80°C, 15 min.). Heat-resistant strains were isolated from 5/215 (2.3%) unheated specimens, and from 4/82 (4.9%) heat-treated specimens.
5. Raw oysters were shown to be markedly contaminated by
C. perfringens, being demonstrable in 100.0 per cent (31/31) of specimens. Heat-resistant
C. perfringens was not isolated from non heat-treated specimens, but from 14/31 (45.2%) heat-treated specimens.
6. The results obtained indicate that the most of
C. perfringens which occur as contaminants of raw meat and other various foods are heat-sensitive strains. However, the isolation rates observed in cultures of heat-treated specimens (80°C or 100°C) suggest a considerably high incidence of contamination of raw meat, oyster, etc. by heat-resistant spores of this organism.
抄録全体を表示