A slice from each product was placed in an airtight bag, in a ventilated cupboard, in an air conditioned office and monitored over a two-week period.
By day four, the Danny's pita pocket, the Baker's Delight bread, Pam's English muffin and the Giannis natural wrap showed signs of mould growth and were deemed inedible.
By day seven, mould was widespread, apart from on the Baker's Delight bread which was only spotted with mould.
The Freya's wrap and slice of Budget brand bread still showed no signs of mould or hardening.
After 20 days, the Budget bread showed no signs of mould but the bread had an unpleasant smell and broke apart easily.
But the Freya's wrap was still perfectly soft and pliable and had another month of freshness promised by a use by-date of April 7 - almost two months after the purchase date.
The Freya's wrap and the Pam's English muffin contain the mould-inhibiting preservative 282 (calcium propionate).
Auckland paediatrician Dr Leila Masson said 282 is linked to irritability and behavioural issues in some children. She said it was of no use to the consumer and was used to speed up production by preventing mould caused when hot bread was put into plastic bags.
"It is unnecessary and I would advise parents to read the ingredients," Masson said. "There are plenty of alternatives."
Masson said she had treated a 3-year-old boy with behavioural issues that she linked to 282 used in bread at his kindergarten.
"As soon as that was eliminated from his diet his behaviour improved," she said.
The Freya's wrap also included three other preservatives that Masson said were best to avoid if food sensitivities were an issue.
Pam's English muffin split was still affected by mould by day four despite using the preservative.
A spokesperson for the company that produces Freya's wraps, Goodman Fielder, said the preservative was safe according to New Zealand food-safety guidelines.
"All our products comply with the food ingredients regulations, which are governed by Food Standards Australia New Zealand (FSanz). We strictly abide by the rules, which are extensive and extremely tight."
Tony Pearce from Danny's said the quick deterioration of its product was expected. He said Danny's prided itself on preservative-free produce that was best used within days or frozen.
"We don't use preservatives so our products are best used fresh or popped in the freezer and used when needed," Pearce said.
Colin Prebble from Giannis said its wraps were preservative-free and were based on an old family recipe from Cyprus rather than from "work by scientists in white coats".
"We have to balance shelf-life against putting unnecessary additives and preservatives into our products," Prebble said.
"We would rather have fewer ingredients and provide a healthy product than have something you can keep for months."
Auckland nutritionist Nikki Hart said strict food regulations meant bread was safe. "As consumers, we don't want bread to go mouldy. We have asked for a longer shelf life and companies have provided that.
"As long as we feed our children a balanced diet we should be okay. We have to trust science."
Leila Masson's healthy lunch box options
• Wholegrain bread with a burger or vege patty and salad
• Hummus with carrot sticks or brown rice crackers
• Seaweed snacks
• Fresh fruit and vegetables
• Fritters made with buckwheat flour, egg, corn and any other chopped vegetables
• Homemade sushi made with avocado, carrot and cucumber
• Homemade muffins baked with wholegrains and grated carrots, courgette and other vegetables
• Leftovers from a healthy dinner
