FDA 3300 refusal charge

According to the FDA, a food rejected under reason 3300: "The label fails to declare all major food allergens present in the product, as required by section 403(w)(1)." 403(w) 801(a)(3)

Is a misbranded food. Consumption of a food containing an allergen by a consumer sensitive to that allergen can be very dangerous.

Sometimes the presence of allergens goes unnoticed by the FBO due to cross-contamination or their presence in raw materials, making it difficult to identify their presence on the final product label.

Should a food whose label does not list the presence of a particular allergen be considered a misbranded or adulterated food?

If the product is formulated as such, then yes it is misbranded. If it is a food previously denied admission by the FDA as "reoffer" without correction, then it is adulterated.