Food Prep & Storage: How to Keep Nutrients Locked In and Freshness Lasting Longer

Author: Chantelle van der Merwe

Registered Dietitian (SA) . PG Dip Diabetes Management (UK). All about Real nutrition for Real, every-day life  

Have you ever wondered whether the way you cook or store your food could be making it less nutritious? As a dietitian, I often see well-intentioned meal prep go sideways—not because of the ingredients, but because of how they’re handled. Here’s the good news: With just a few smart tweaks, you can preserve more nutrients, reduce waste, and get better flavour and value out of every fruit and veggie in your kitchen.

Let’s unpack two key pillars of better health in your kitchen: Preparation and Storage.

How Cooking Methods Impact Nutrition:
Cooking isn't just about flavour—it also changes how our bodies absorb nutrients. While it improves digestibility and enhances some nutrients (like lycopene in tomatoes or protein in eggs), it can also break down fragile vitamins like vitamin C and many B vitamins.

To get the most nutritional bang for your buck:

✅ Do:

• Steam, microwave, or stir-fry veggies where possible. These methods use less water and gentler heat—perfect for preserving water-soluble nutrients.
• Keep cooking time short, especially for leafy greens and cruciferous veg.
• Cut veggies after cooking when possible to reduce exposure to heat and air.
• Use cooking liquids in soups and stews. Nutrients that leach out during boiling can be reclaimed this way.
• Leave the skins on—they’re packed with fiber and antioxidants.

❌ Don’t:

• Boil vegetables for long periods, especially in lots of water.
• Peel produce unnecessarily—this can increase oxidation and vitamin loss.
• Use baking soda when cooking vegetables. Although it may keep the color vibrant, it speeds up vitamin C breakdown.

​Fun fact: Steaming spinach preserves up to 91% of its vitamin C, while boiling it can slash that number in half!

Fresh Produce Storage:
Nutrient-rich produce can lose its power (and appeal) quickly if not stored correctly. Knowing where each fruit or veggie belongs can help it last longer, taste better, and retain more nutrients.

Room Temperature vs. Fridge: Quick Guidelines

• Ripen on the counter, then chill to extend freshness: This works well for avocados, bananas, peaches, and pears.
• Straight to the fridge: Most vegetables (like broccoli, carrots, leafy greens) last longer when chilled.
• Leave at room temperature:
  • Tomatoes – Chilling dulls their flavour.
  • Garlic and onions – Keep them in a dry, airy place (away from potatoes!).
  • Potatoes and sweet potatoes – Store in a cool, dark spot—not in the fridge.
  • Pumpkin and butternut – Happy in a pantry or under-counter shelf.

Fruits that like it cold from the start:

• Berries and grapes – They spoil fast and need the cold. Don’t wash until you’re ready to eat them.

Fridge Smarts: Are You Using Your Crisper Drawers Right?
Your fridge drawers do more than just store salad ingredients—they regulate humidity, which impacts how well your produce lasts.

Here’s how to use those sliding vents like a pro:

• High Humidity (vent closed): Best for leafy greens and vegetables that wilt—spinach, kale, lettuce.
• Low Humidity (vent open): Ideal for fruits that produce ethylene gas, like apples, avocados, and pears.
• Only one drawer or no vent? It defaults to high humidity—stick to veg.
• Two drawers? Use one for high humidity (veg) and the other for low humidity (fruit).

Tip: Keep crisper drawers about two-thirds full. Overpacking reduces airflow and speeds up spoilage.

Containers Matter Too:
Skip the plastic if you can—especially for hot food or regular use.

• Best choices: Glass (non-reactive, odour-resistant), food-grade stainless steel, or BPA-free silicone containers.
• Avoid old or scratched plastic, as it may leach chemicals like BPA over time, especially when reheated.

Extra Storage Tips to Keep in Mind: 

• Don’t pre-wash produce. It speeds up spoilage by adding extra moisture. Wash just before use.
• Keep produce whole until you're ready to eat or cook. Cutting increases surface area, accelerating oxidation and nutrient loss.
• Store herbs smartly:
  • Soft herbs (like parsley, coriander): Treat like flowers—stems in a glass of water, loosely covered.
  • Hard herbs (like rosemary, thyme): Wrap in a damp paper towel and place in a sealed bag in the fridge.

Food is fuel, but it’s also an investment—into your health, your wallet, and the planet. With a few mindful cooking and storage habits, you can protect that investment, waste less, and get more nutrients with every bite.
​
Need help personalising your nutrition game? Get in touch—I’d love to help you make your food work smarter for your health.

I had the pleasure of being interviewed by Woolworths TASTE Magazine on “The Healthiest Ways to Store, Eat and Serve Fruit and Vegetables.” Click here, for the link to read the full article and get even more practical tips on getting the most nutritional bang for your buck!