A Change in Cake Selection? Allergy-Causing "Walnuts" Suddenly Rise to 2nd Place—Unexpected Risks Lurking in Christmas and What You Can Do Now

1) What's Happening Now? — The Background Behind "Walnuts" Becoming a "Major Allergen"

When people hear "causes of food allergies," many think of eggs, milk, and wheat. However, in recent years, the presence of tree nuts has been rapidly increasing, with "walnuts" standing out in particular.

According to meeting materials from the Consumer Affairs Agency (based on a fact-finding survey), the initial cause of food allergies varies with age, but walnuts rank 2nd for ages 1-2, 1st for ages 3-6, and 1st for ages 7-17, placing them high across multiple age groups. Consumer Affairs Agency
Considering that "cake = children also eat," this is a significant change.

So why "walnuts"? There isn't just one factor, but the following points often overlap in our daily food environment.

• Ease of Incorporation into Baked Goods and Western Confections
  Due to their appealing aroma, texture, and nutritional image, walnuts are widely used in cake batter, sponge mixes, crumbles, caramel nuts, pralines, nougat, cookie bases, and as an accent in raw chocolate.
  
  

• Difficult to Judge by Appearance
  While whole nuts can be noticed, when chopped, ground, pasted, or mixed (nut mixes), they become difficult to distinguish by appearance.
  
  

• The Risk of "Even a Small Amount" May Be Increasing
  Analysis by the National Center for Child Health and Development estimates the elicitation threshold (ED) from food oral challenge test data, indicating that since 2020, reactions occur with smaller amounts of walnuts. National Center for Child Health and Development
  This means the feeling that "a little was okay" or "it was fine before" may no longer apply.

2) Why the Risk Increases at Christmas — "Special Sweets" Are Particularly Dangerous

Around Christmas, walnuts are more likely to be mixed in than usual. The reason is simple: the number of products using nuts increases, and production and sales sites enter a busy period.

2-1. Christmas Sweets Tend to Feature Nuts

• Fermented sweets like Stollen and Panettone

• Nut-filled chocolates, pralines, roasted nut toppings

• Wreath-style decorations (nuts, decorative chocolates, cookies)

• Cookie assortments, baked goods sets (prone to mixing)

Not only the "cake" itself, but also "accompanying baked goods" in the same box, the crunch sprinkled on top, and the **base (tart base, cookie base)** supporting the cake can also be the cause.

2-2. During Busy Periods, Managing "Contamination (Unintentional Mixing)" Becomes Difficult

When making nut-containing and nut-free products in parallel in the same workshop, on the same line, or with the same tools, powders and fragments can easily transfer.
Especially, chopped nuts and nut powders tend to scatter and remain on tools and workbenches, which is troublesome.

3) How Has the Labeling System Changed? — "Walnuts" Have Become "Mandatory Labeling"

In Japan, there is an allergen labeling system for packaged processed foods, etc.
"Walnuts" were previously on the recommended (voluntary) side, but due to the increase in cases, the system was revised, and as of March 9, 2023, they transitioned to mandatory labeling (specified ingredients). Consumer Affairs Agency+1
The transitional measure is set until March 31, 2025. Consumer Affairs Agency+1

Additionally, national documents indicate that in dining and takeout (in-store cooking, in-store sales, etc.), there are areas where labeling is "not mandatory," emphasizing the importance of information provision and the potential life-threatening nature of misinformation. Ministry of Health, Labour and Welfare
In other words, while package labeling has been strengthened, not all purchasing scenarios have become safe, which is an important point.

4) Three Pitfalls of "Feeling Safe by Checking Labels"

Pitfall ①: In-store Sales and Cut Sales Lower the Granularity of Labeling

When boxing whole cakes in-store, labels may become simplified, or reliance on verbal guidance may occur.
In cases where "you can't get a paper with the ingredients" or "there's no information on the web," the safest decision is **"unable to confirm = do not eat."**

Pitfall ②: "Nut" Labeling or "Mix" Makes It Hard to Read the Presence of Walnuts

In some products, walnuts may be grouped with other tree nuts, making explanations abstract.
For those with allergies (or their families), it's important to specifically confirm that "there are no walnuts."

Pitfall ③: Even Products with the Same Name Can Have Recipe Changes Year by Year

Christmas products are prone to annual renewals, making it easy for "the cake that was okay last year" to not be okay this year.
It's necessary to judge based on this year's ingredient information, not the "product name."

5) Practical Checklist for Buying Christmas Cakes (For Families and Buyers)

5-1. What to Check Before Buying (Common for Online and In-store)

• Check if "walnuts" are listed in the ingredients section.

• Check for elements that pair well with nuts, such as "nuts," "tree nuts," "praline," "nougat," "croquant," "dacquoise," "financier," etc.

• Note any warnings about "same factory" or "same line" (if present)

• If there are uncertainties, inquire with the store in advance (phone or web).

  • National guidelines also state that providing information in advance via the web, etc., is desirable for dining out, and that the danger of answering based on independent judgment when unsure is emphasized. Ministry of Health, Labour and Welfare

5-2. Question Templates When Asking in Stores (Short and Specific)

• "Does this product contain walnuts?"

• "Are there **processes that handle walnuts (same tools, same base)**?"

• "Can I check the **list of ingredients (images are acceptable)**?"

※In cases of ambiguous responses ("probably okay," "I don't think it's in there"), it's prudent to avoid. National documents also emphasize that providing incorrect information can lead to accidents. Ministry of Health, Labour and Welfare

5-3. Precautions When Eating at Home

• Do not share knives or tongs for serving

• If nut-containing sweets are on the same table, ensure thorough cleaning of plates, hand wipes, and children's handwashing

• For those with severe allergies, follow the instructions of your primary care physician and prepare necessary medications (e.g., EpiPen)

6) For Businesses and Event Organizers — Prepare with the Assumption that "Accidents Happen During Busy Periods"

Christmas marks the peak of busyness for workshops, stores, and event sites. Therefore, the key is to implement "practices that can be maintained on-site."

6-1. Minimum Management (Realistic Even for Small Stores)

• Separate workbenches, bowls, and whisks for walnut recipes as much as possible

• Schedule chopped nut work for "last" (as scattering is likely to spread)

• Create an "allergen table (list)" for staff to view the same information

• Standardize verbal responses: "Check with the person in charge when unsure"

  • National documents also state not to answer based on independent judgment when unsure, and that the accuracy of information is of utmost importance. Ministry of Health, Labour and Welfare

6-2. Innovations in Labeling and Guidance (Balancing Safety and Sales)

• Clearly state allergens (specified ingredients, etc.) on reservation forms and product cards

• Create an "allergen information" page on the web menu

• Only claim "complete removal" when the system (separate cooking, cleaning, ingredient management) is in place

7) In Case of Emergency: Signs of Symptoms and Emergency Thinking (For the General Public)

Symptoms of food allergies vary by person and range from mild to severe. Generally, they include skin hives, oral discomfort, coughing, difficulty breathing, abdominal pain