Final answer:
Parents should prevent infant botulism by not giving honey to children under one year old and by following proper sterilization and canning procedures when preserving food.
Step-by-step explanation:
For parents with children at risk for botulism, the most important instruction is to avoid giving honey to children less than 12 months old. The Clostridium botulinum bacteria, which causes botulism, can be present in honey. Because infant immune systems are not fully developed, they are particularly vulnerable to the bacteria. Additionally, when canning food at home, ensure that proper sterilization and canning procedures are followed to prevent creating an anaerobic environment in which Clostridium botulinum can thrive.