Nutritionists Warn: Top Food Poisoning Risk in Meal Prepping is 'Re-storing Leftovers'
A survey of 100 registered dietitians by Emiish's 'Nutritionist Lab®' identifies 're-storing leftovers' (37%) and 'leaving food at room temperature' (32%) as the top risks for food poisoning. Experts recommend cooling food to below 20°C within 30 minutes and consuming it within 2-3 days.
📋 Article Processing Timeline
- 📰 Published: May 19, 2026 at 22:10
- 🔍 Collected: May 19, 2026 at 13:31
- 🤖 AI Analyzed: May 28, 2026 at 16:12 (218h 40m after Collected)
Emiish Co., Ltd. (Meguro-ku, Tokyo; CEO Maki Shibata) conducted a survey on 'meal prepping' among 100 nutritionists and registered dietitians belonging to the professional community 'Nutritionist Lab®.'
As the rainy season begins, increasing humidity raises the risk of food poisoning in households. The survey revealed significant risks in common daily habits.
### Top Behaviors Increasing Food Poisoning Risk
1. **Re-storing leftovers to eat the next day or later (37%)**
2. **Leaving food at room temperature until it cools down completely after cooking (32%)**
3. **Insufficient reheating (15%)**
### Most Effective Countermeasures
* **Thoroughly heating to the core (70 votes)**
* **Quickly cooling food within 30 minutes of cooking and storing in the fridge/freezer (62 votes)**
Saori Tomita, a registered dietitian and chef, emphasizes the importance of 'rapid cooling.' Citing standards for mass catering—cooling food to below 20°C within 30 minutes—she suggests using ice packs, transferring food to stainless steel trays, or storing in smaller portions to speed up cooling at home. While 82% of experts use vinegar or pickled plums (umeboshi) for their preservative effects, she notes these only make food 'less perishable,' not 'spoiling-proof.' The safe guideline remains to consume prepped meals within 2 to 3 days.
As the rainy season begins, increasing humidity raises the risk of food poisoning in households. The survey revealed significant risks in common daily habits.
### Top Behaviors Increasing Food Poisoning Risk
1. **Re-storing leftovers to eat the next day or later (37%)**
2. **Leaving food at room temperature until it cools down completely after cooking (32%)**
3. **Insufficient reheating (15%)**
### Most Effective Countermeasures
* **Thoroughly heating to the core (70 votes)**
* **Quickly cooling food within 30 minutes of cooking and storing in the fridge/freezer (62 votes)**
Saori Tomita, a registered dietitian and chef, emphasizes the importance of 'rapid cooling.' Citing standards for mass catering—cooling food to below 20°C within 30 minutes—she suggests using ice packs, transferring food to stainless steel trays, or storing in smaller portions to speed up cooling at home. While 82% of experts use vinegar or pickled plums (umeboshi) for their preservative effects, she notes these only make food 'less perishable,' not 'spoiling-proof.' The safe guideline remains to consume prepped meals within 2 to 3 days.
FAQ
作り置きおかずで最も食中毒リスクが高い行動は何ですか？
アンケート調査の結果、「食べ残しを再び保存し、翌日以降に食べる」ことが37％で第1位となり、最もリスクが高いとされています。
調理後の冷却について、専門家はどのような基準を推奨していますか？
大量調理施設衛生管理マニュアルに基づき、調理後30分以内に中心温度を20℃以下まで冷却することを推奨しています。
家庭で素早くおかずを冷ますための具体的な方法は？
保冷剤を敷く、熱伝導率の良いステンレスバットへ移す、小分けにして保存するといった工夫が有効です。
食中毒対策として有効な食材はありますか？
栄養士の82％が、防腐・静菌効果のあるお酢や梅干しを活用したメニュー（マリネや南蛮漬けなど）を推奨しています。
作り置きおかずは何日以内に食べるべきですか？
無理に長持ちさせようとせず、衛生管理を徹底した上で2〜3日を目安に食べ切ることが安心につながります。