Formula Feeding

Formula Feeding: A Professional Guide to Choosing, Preparing, and Feeding Safely

When breastfeeding is not possible or supplemented, infant formula provides complete nutrition for your baby’s growth and development. Proper selection, preparation, and feeding techniques are essential for your baby’s health and safety. This guide provides evidence-based information on choosing formula, safe preparation, transitioning between formulas, and selecting appropriate bottles and teats.

*Disclaimer: This information is for educational purposes only and does not replace professional medical advice. Always consult your health visitor, GP, or paediatrician for concerns about your baby.*

Part 1: Choosing and Storing Infant Formula

How to Choose a Formula for Your Baby

For healthy term infants, standard cow’s milk-based infant formula (often labelled “Stage 1”) is appropriate from birth to 12 months .

Key considerations when choosing:

Factor	What to Know
Stage	Infant formula (Stage 1) is suitable throughout the first year. Follow-on formula (Stage 2) after 6 months is unnecessary and confers no health advantages .
Brand	All infant formulas must comply with strict nutritional standards, so ingredients are generally similar across brands . Price differences do not reflect nutritional superiority.
Iron content	Most standard formulas are iron-fortified, which is important for preventing iron deficiency .
Special formulas	Only use formulas for premature babies, anti-reflux, lactose-free, or hydrolysed proteins on medical advice .

Note: A 2022 study found that nearly half (46.3%) of parents incorrectly prepared formula, highlighting the importance of following instructions carefully regardless of brand choice .

Cow Milk Formula vs Goat Milk Formula: Which Is Better?

Recent research provides interesting insights into the differences:

– Digestibility: A 2025 in vitro study found that goat milk-based infant formula (GMF) exhibited significantly higher protein and lipid digestion rates than cow milk-based formula (CMF) under simulated infant conditions .
– Protein digestion: After 120 minutes of intestinal digestion, protein digestibility reached 28.3% for GMF, compared to 16.2% for CMF .
– Lipid profile: GMF contains higher proportions of short- and medium-chain fatty acids and sn-2 palmitic acid, which may contribute to better fat absorption .
– Similarity to breast milk: The similarity score of lipid digestion products between GMF and human milk reached 85.5, significantly surpassing that of CMF (67.12) .

Bottom line: Both cow and goat milk formulas are safe and nutritionally complete options. Goat milk formula may offer easier digestion for some infants, but individual tolerance varies. Choose based on your baby’s acceptance and any medical considerations.

How to Store Infant Formula Properly

Unopened formula:
– Store in a cool, dry place (kitchen cupboard, not refrigerator)
– Avoid extreme temperatures

Opened powder formula:
– Keep lid tightly closed
– Store in cool, dry place (not refrigerator)
– Use within **1 month** of opening

Prepared formula:
– Use immediately if possible
– If refrigerated immediately after preparation: use within **24 hours**
– If left at room temperature: use within **2 hours** of preparation
– Once feeding begins: use within **1 hour**, then discard unfinished formula

Part 2: Preparing Formula Safely

Why Add Water First, Then Powder

Critical safety rule: Always put water in the bottle first, then add powder .

Reasons:
1. Accuracy: Adding powder first can result in incorrect concentration because powder displaces water volume .
2. Safety: Too much or too little water can cause diarrhea, constipation, dehydration, or other problems for your baby .
3. Dissolving: Water-first helps powder dissolve properly.

What Water to Use for Formula

Water Type	Recommendation
Tap water	Usually acceptable if safe. Boil and cool to at least 70°C before mixing .
Bottled water	Choose water labeled for infants and sterile. Still (not sparkling) only. Must still be boiled to 70°C .
Boiled water	Boil fresh tap water in a kettle. If you boil 1 litre, it stays above 70°C for up to 30 minutes .
Mineral water	Not recommended due to high mineral content that may strain baby’s kidneys .
Previously boiled water	Do not re-use old boiled water—always use freshly boiled water .

Temperature is crucial: Water must be **at least 70°C** when mixed with powder to kill harmful bacteria like Cronobacter and Salmonella that may be present in powdered formula .

Step-by-Step: How to Prepare Formula Correctly

1. Wash hands thoroughly with soap and warm water .
2. Clean surfaces where you’ll prepare the feed .
3. Use sterilised bottles and teats .
4. Boil fresh tap water in a kettle. If using 1 litre, use within 30 minutes to ensure it stays above 70°C .
5. Pour correct amount of hot water into the sterilised bottle .
6. Add exact number of level scoops using only the scoop provided with that formula. Level off with a clean knife—do not pack or heap .
7. Cap bottle and shake well until powder is fully dissolved .
8. Cool to feeding temperature by holding bottle under cold running water or placing in a container of cold water. Do not submerge teat .
9. Test temperature by shaking a few drops onto the inside of your wrist—it should feel lukewarm, not hot .

Never:
– Add extra scoops or less powder than directed
– Add cereal or other substances to the bottle
– Heat formula in a microwave (creates hot spots that can burn baby’s mouth)
– Use formula preparation machines—the NHS advises against them as they may not effectively kill bacteria

Common Preparation Mistakes to Avoid

A 2022 study found that nearly half of parents incorrectly prepared formula . Common errors include:

– Incorrect water-to-powder ratio
– Using water that’s not hot enough
– Not sterilising equipment
– Storing prepared formula incorrectly
– Using outdated formula

Part 3: When Baby Refuses Formula

Why Some Babies Refuse Formula

Several factors can cause formula refusal:

Cause	Explanation
Taste preference	Formula tastes different from breast milk. Some babies need time to adjust.
Nipple confusion	Different teat shapes and flow rates can affect acceptance.
Temperature preference	Some babies prefer warm milk; others accept room temperature.
Illness or discomfort	Teething, ear infections, or stuffy nose can make feeding uncomfortable .
Physiological anorexia	Common around 3-6 months when growth slows and babies become more distracted by surroundings .
Taste changes	Different formula brands have slightly different flavours .

Signs of Physiological Milk Refusal (厌奶)

Babies aged 3-6 months commonly experience a “nursing strike” or milk refusal period due to developmental changes :

– Good energy and activity but no interest in feeding
– Turns head away during feeding or cries
– Pushes teat out with tongue
– Easily distracted during feeds
– Allows milk to dribble out without swallowing

Red flags requiring medical attention :
– Refusal lasting >2 months
– Weight not increasing appropriately
– Weight percentile dropping across two growth curves
– Accompanying symptoms: abdominal distension, vomiting, fever, rapid breathing, decreased activity

What to Do When Baby Refuses Formula

1. Don’t force feed – This can create negative associations with feeding .
2. Feed on demand – Follow baby’s cues rather than rigid schedules .
3. Create calm environment – Feed in a quiet, dimly lit room without distractions .
4. Try different positions – Experiment with feeding positions .
5. Check teat flow – Formula should drip about one drop per second when bottle is inverted .
6. Feed when drowsy – Some babies feed better when half-asleep .
7. Increase hunger – Engage baby in play and activity between feeds .
8. Consider cup feeding – For babies over 4-6 months, introducing a cup may provide novelty .
9. Rule out illness – Check for signs of teething, ear infection, or congestion.

Part 4: Switching Formulas (转奶)

When to Consider Switching Formulas

Healthcare professionals generally do not encourage switching brands for minor issues . However, switching may be needed when:

– Medical necessity: Confirmed cow’s milk protein allergy requiring hypoallergenic formula (under medical supervision)
– Persistent intolerance: Ongoing digestive issues (severe reflux, constipation, diarrhea) not improving with current formula
– Specialised needs: Preterm infants transitioning to standard formula
– Genuine acceptance issues: Baby consistently refuses current formula despite trying all strategies

Note: If baby is under 6 months and currently on cow’s milk-based infant formula (Stage 1), you can switch directly to another brand of cow’s milk-based formula . Babies under 6 months should not receive follow-on formula .

How to Switch Formulas Safely

There is no specific procedure for switching . Two approaches:

Approach	Method
Direct switch	If baby accepts the new taste, simply replace the old formula with new formula completely .
Gradual transition	Introduce 1-2 feeds of new formula daily, gradually increasing until fully replaced .

Critical safety rule: Never mix two different brands of formula powder when preparing feeds, as they have different water-to-powder ratios .

What to Expect When Switching

– Stool changes: Different formulas contain varying levels of iron, probiotics, and other ingredients, which may affect stool frequency, texture, and colour .
– Temporary adjustment: Some babies need a few days to adjust to new taste.
– Monitor for tolerance: Watch for signs of intolerance (excessive gas, vomiting, rash).

When to Pause or Stop Switching

Temporarily pause or revert to previous formula if baby shows:

– Persistent vomiting
– Diarrhea
– Blood in stool
– Rash or signs of allergic reaction
– Significant feeding refusal
– Poor weight gain

Seek medical advice if these symptoms occur.

Part 5: Bottles and Teats – Selection, Cleaning, and Lifespan

How to Choose Bottles

Feature	Considerations
Material	Glass (durable, heavy) or BPA-free plastic (lightweight, unbreakable)
Shape	Standard, angled, or wide-neck (easier filling and cleaning)
Size	Small bottles (120-150ml) for newborns; larger (250-300ml) for older babies
Ventilation system	Anti-colic features may reduce air swallowing
Compatibility	Ensure teats fit the bottle brand

How to Choose Teats

Feature	Options	Considerations
Material	Silicone (clear, firm, longer-lasting) or Latex (brown, softer, shorter lifespan)	Latex may cause allergies in sensitive babies
Shape	Standard, orthodontic, wide-base	Mimics breast shape for easier transition
Flow rate	Slow (newborn), Medium (3-6 months), Fast (6+ months), Variable flow	Flow too fast = choking; too slow = frustration
Size	Age-marked on packaging	Replace as baby grows

Testing flow rate: When bottle is inverted, formula should drip at about **one drop per second** .

Do Bottles Have a Shelf Life?

**Yes, bottles have a limited lifespan.**

Material	Lifespan	Replacement Signs
Plastic bottles	4-6 months with daily use	Cracks, scratches, cloudy appearance, warping
Glass bottles	Indefinite with care	Chips, cracks
Silicone bottles	6-12 months	Sticky texture, tears

How Long Do Teats Last?

**Teats should be replaced every 4-8 weeks**, or immediately if you notice:

– Cracks, tears, or holes
– Sticky or swollen appearance (latex)
– Discolouration
– Changes in flow (too fast or too slow)
– Weak suction or collapse during feeding

How to Clean and Sterilise Bottles and Teats

Before first use: All new bottles and teats must be sterilised.

After every use: Clean and sterilise all feeding items .

Step 1: Cleaning

Hand washing method :
1. Wash hands with soap and water
2. Disassemble all parts (bottles, teats, caps, rings)
3. Rinse under running water
4. Fill a clean basin (used only for infant feeding items) with hot water and add soap
5. Scrub with a clean brush (used only for infant feeding items)—squeeze water through teat holes
6. Rinse all items again under running water
7. Air-dry on a clean dish towel or paper towel (do not pat-dry, which can transfer germs)
8. Once completely dry, reassemble and store in clean area
9. Wash basin and brush after each use and air-dry

Dishwasher method (if dishwasher-safe) :
1. Disassemble and rinse under running water
2. Place in dishwasher
3. Use hot water setting and heated drying (sanitising) cycle if available
4. Wash hands before removing items
5. If not completely dry, air-dry on clean towel

Note: The scoop for powdered formula only needs washing if it becomes wet or dirty (e.g., dropped on floor). Dry completely before returning to container .

Step 2: Sterilising

After cleaning, sterilise using one of these methods:

Method	Instructions
Boiling	Boil items in water for 5-10 minutes. Ensure fully submerged.
Electric steam steriliser	Follow manufacturer’s instructions
Microwave steriliser	Follow manufacturer’s instructions
Cold water sterilising	Use sterilising solution according to instructions
Dishwasher	If dishwasher has sanitising cycle

Can You Use Boiling Water to Sterilise?

**Yes, boiling is an effective sterilisation method:**

1. Ensure bottles, teats, and other items are thoroughly cleaned first
2. Submerge completely in boiling water
3. Boil for at least 5 minutes
4. Remove with sterilised tongs
5. Air-dry on clean paper towel or dish towel

However, simply rinsing with boiled water is NOT sufficient for sterilisation—items must be fully immersed in boiling water for the required time or processed through another sterilisation method.

Summary Table: Key Points at a Glance

Topic	Key Messages
Formula choice	Stage 1 formula suitable 0-12 months; all brands meet nutritional standards
Goat vs cow	Goat formula may offer easier digestion, but both are safe options
Storage	Opened powder: use within 1 month. Prepared formula: 24 hours in fridge, 2 hours at room temp, 1 hour after feeding starts
Preparation	Water first, then powder. Use freshly boiled water at ≥70°C. Follow instructions exactly .
Water	Freshly boiled tap water cooled to 70°C is ideal. Not mineral water .
Formula refusal	Common 3-6 months. Don’t force feed; create calm environment; check teat flow .
Switching formulas	Direct replacement is fine. Never mix two brands in one bottle .
Bottle lifespan	Plastic: 4-6 months; Glass: indefinite if undamaged
Teat lifespan	Replace every 4-8 weeks or at signs of damage
Sterilisation	Clean then sterilise every use until 12 months. Boiling for 5-10 minutes works .

**Key Resources:**
– NHS Start for Life: www.nhs.uk/start-for-life
– First Steps Nutrition Trust: www.firststepsnutrition.org
– Family Health Service (Hong Kong): www.fhs.gov.hk

*References available upon request. Key sources: PubMed 2022 , HealthyWA , Northwestern Medicine , ScienceDirect 2025 , Hong Kong FHS , Just One Norfolk , China Medical University Hospital .*