Food poisoning usually disappears within a few days, causing no further problems. When the mother has food poisoning, it rarely poses any danger to the breast-fed baby, as the enzymes in the baby’s stomach usually kill the bacteria.1 However, the mother should increase her fluid intake to prevent dehydration and ensure that she follows good general hygiene practices, particularly washing her hands before handling the baby.
If the mother’s symptoms last for more than 3 days or she becomes increasingly unwell, medical advice should be sought. If an antibiotic is prescribed, it should be one considered safe with breast-feeding.

Reference1. Lawrence RA, Lawrence RM. Medical complications of the mother. In: Lawrence RA, Lawrence RM (eds). Breastfeeding: A Guide for the Medical Profession. (5th edn.)  St Louis, MO, USA: CV Mosby, 1999

From: Journal of Family Health Care Bulletin. Directory of Breast-Feeding Advice. December 2009. Published with JFHC 2009; 19(6). http://www.jfhc.co.uk/images/stories/breastfeeding.pdf