Sources and Further Reading

Core food-safety principles and storage guidance were checked against official sources. Local rules should take priority.

• World Health Organization — Five Keys to Safer Food
• USDA FSIS — Keeping Bag Lunches Safe
• USDA FSIS — Food Safety Basics
• Health Canada — Safe Food Handling at the Grocery Store
• UK Food Standards Agency — Food Poisoning and Safe Chilling

Regional sandwich pages avoid claiming a single uncontested origin where local histories and terminology differ.