Bento booster /Heat ingredients to prevent food poisoning

The Yomiuri Shimbun

The Yomiuri ShimbunThis series introduces everyday techniques to make bento lunches.

When making bento lunch boxes during hot and humid weather, it’s crucial to take precautions to prevent food poisoning. According to Reiko Tsunabuchi, a cooking instructor at the Ecole de Cuisine Egami in Tokyo, it’s important to heat ingredients until they are cooked through and sufficiently cool them before arranging them in the box. She also recommends strong seasonings.

The simplest way to prevent food poisoning is to stop harmful bacteria from contaminating your food. We need to be especially careful when preparing ingredients for a bento, as a certain amount of time will have elapsed between preparation and consumption.

What kind of dishes are most suitable for bento lunches? “I recommend dishes that can be cooked through,” Tsunabuchi said.

For example, kinpira stir-fried sliced vegetables seasoned with sugar and soy sauce and thin ginger-flavored slices of meat are suitable choices. While tamagoyaki is typically a common dish in bento lunches, it should be avoided in summer, as sometimes the center remains raw after cooking. Instead, Tsunabuchi suggests preparing a thinly cooked omelet and rolling it.

One tip to keep in mind is that the use of spices such as ginger, wasabi and red chili pepper or vinegar will help prevent food from spoiling. This installment introduces ginger-flavored pork, egg rolls using wasabi, and kinpira using red chili pepper for a bento lunch box. Broccoli is also soaked in vinegar for about one hour to make pickled broccoli.

After cooking these dishes, cool them sufficiently and drain excess liquids. Use small separators to arrange the cooked dishes in a bento box so that liquids from one dish will not affect the others. Stopping cross contamination helps to prevent the other dishes from spoiling. It’s also important not to directly touch dishes with your hands when arranging them in the box.

Before putting cooked rice in the box, it should also be sufficiently cooled.

When making onigiri rice balls, particular care must be taken at the preparation stage. Make sure to use enough salt and use plastic wrap to make the rice balls so that any bacteria on your hands is not transferred to the rice balls.

“If you want to wrap onigiri for transport, first cool the rice balls and employ a new piece of plastic wrap. If you want to wrap them in nori dried seaweed, do this right before you intend to eat them,” Tsunabuchi says. As ingredients, her recommendations are ginger pickled in sweetened vinegar, umeboshi salt-preserved plums and green shiso leaves, as these have an antiseptic effect. Finely chop and mix these into the rice.

“When transporting the lunch box, you should use cold packs and a cool bag,” she said.

Sterilize your lunch box

According to Tsunabuchi, it’s important to make an extra effort when storing a lunch box and using it. Depending on the types of materials, a lunch box should be washed with detergent and then sterilized with boiling water or antibacterial kitchen cleaner. Wipe the box with a clean dishcloth and dry well. Before using the box again, wipe the inside with kitchen paper soaked in a small amount of vinegar.


■ Heat ingredients until cooked through

■ Cool the cooked ingredients sufficiently, drain excess liquids before arranging them in the lunch box

■ Use spices such as ginger and red chili pepper or vinegar

Ingredients and directions

Rolled omelet with wasabi

1 egg / 1 tsp sugar / pinch of salt / pinch of wasabi paste

1. Beat egg and add sugar, salt and wasabi to beaten egg. Mix, and divide resulting mixture in half.

2. Make two paper-thin omelets. After they have cooled, roll these using plastic wrap without directly touching them with your hands. Cut the omelet into bite-size portions.

Pickled broccoli

1 head broccoli / 1 clove garlic

1 red chili pepper / black pepper

ready-made sushi vinegar

1. Divide broccoli into bite-size portions, boil in salted hot water and drain in a colander.

2. Put broccoli, peeled garlic clove cut in half lengthwise, red chili pepper and black pepper in a container. Pour vinegar over the ingredients and leave for about one hour. Drain excess liquid.


*Ingredients are listed in amounts suitable for easily cooking each dish.

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