Vegetable juice aids the recovery of heated spores of non-proteolytic Clostridium botulinum

Heating spores of non-proteolytic Clostridium botulinum at 85C for 2 min followed by plating on a standard laboratory medium reduced the count of viable spores by a factor of greater than 10⁴. A similar result was obtained when the plating medium was supplemented with juice from courgette, carrot or mung bean sprout. When plating was on media supplemented with hen egg white lysozyme or juice from turnip, swede, flat bean, cabbage or potato, heating at 85C for 10 min did not reduce the viable count by a factor of 10⁴. Thus these vegetable juices increased the measured heat resistance of spores of non-proteolytic Cl. botulinum . These findings are relevant to the safety of minimally processed (e.g. sous-vide ) foods.