What preventive measure is important for infants to avoid botulism?

Avoiding raw honey is a crucial preventive measure for infants to avoid botulism because honey can contain spores of the bacterium Clostridium botulinum. Infants, particularly those under one year of age, have immature digestive systems that are not fully capable of handling these spores. If ingested, the spores can germinate in the gut and produce a potent toxin that leads to infant botulism, a serious condition that can cause muscle weakness and respiratory problems.

In contrast, the other options listed do not directly address the risk of botulism in infants. The MMR vaccine is important for preventing measles, mumps, and rubella but does not impact botulism risk. Wearing masks in crowded places is a general public health measure that can help prevent respiratory infections, but it is not relevant to botulism prevention. Breastfeeding exclusively is beneficial for overall infant nutrition and immune support, but it does not specifically prevent botulism related to honey consumption.