Non-dairy creamer may contain which substance that requires kosher certification?

Non-dairy creamers often contain casein, which is a protein derived from milk. Although they are labeled as "non-dairy," these creamers can still include casein, making them unsuitable for individuals who observe kosher dietary laws, particularly those who avoid dairy products. Kosher certification is important because the presence of casein indicates that the product may not be strictly non-dairy as it contains a dairy-derived ingredient, which can lead to issues with meat and dairy separation in kosher diets.

In contrast, while gluten, soy, and lactose may be relevant to dietary concerns, they do not necessitate kosher certification in the same way casein does. Many soy products are naturally kosher and can be prepared in ways that comply with kosher laws. Lactose, being a sugar found in milk, is not a protein and is typically overlooked in discussions of kosher dairy versus non-dairy designations. Additionally, gluten is primarily a protein found in wheat and is not inherently tied to the dairy classification, thus doesn't trigger the same kosher concerns as casein.