Most of us want to do our bit to reduce our environmental footprint, whether that involves using a bag for life, taking a travel cup to coffee shops or doing our laundry at a lower temperature.
But according to the experts, some of these sustainable practices, while brilliant for the planet, could actually be harming our health.
Water bottle warning
Reusable water bottles save thousands of tons of single-use plastic bottles from landfill. They also carry a risk of infection, says Dr Primrose Freestone, an associate professor in clinical microbiology at Leicester University.
“Research has shown that if you don’t wash your water bottle appropriately and regularly, bacteria and moulds can build up on the bottle surface and interior that, if swallowed, could potentially make you very ill indeed,” she explains.
“In one study, US water filtration company WaterFilterGuru found that the levels of intestinal bacteria such as E. coli in typical water bottles were higher than those found on toilet seats.
“It’s important you regularly clean your bottle, like you would any food-related crockery. Contaminated water can harm your health, causing gut upsets like diarrhoea and vomiting and, if moulds are present, possibly allergies too.”
Dr Freestone advises using washing-up liquid with hot water above 60C as this temperature kills most pathogens. “Swirl the detergent and water around and leave for 10 minutes or so,” she says. “Then rinse well with hot water and allow the bottle to dry – -overnight is best, as thorough drying is also antimicrobial.
“For more heavy contamination (from long usage without washing), add a half vinegar/water mixture and soak for several days. Afterwards, rinse well, then wash out microbial residual debris using detergent and hot water. Swirl, then rinse again and dry. It’s also important to clean lids, or any attachments such as straws as these can also harbour microbes. The type of liquid you put into your water bottle has a major effect on what then grows inside,” adds Dr Freestone. “Fluids to particularly avoid include protein shakes, energy drinks, fruit juices or anything containing sugar as these nutrients can stimulate growth of any bacteria or mould present.”
Beware ‘bag-teria’
Researchers at the University of Arizona and Loma Linda University found bacteria, including e-coli, in 99 per cent of the reusable grocery bags they tested. It’s no surprise to Dr Freestone, who saw similar results in her own survey. “Raw meat, fish and fruit and vegetables are covered in bacteria and fungi, and so is the packaging,” she says.
The good news? In Dr Freestone’s research it took just three to four spays of an antibacterial surface spray to thoroughly disinfect the plastic bags. “For fabric bags, a hot wash at least once a week and thorough drying will help keep bacteria at bay,” she adds. “However, if raw meat or poultry blood leaks into any bag you should consider disposing of it to avoid stomach bugs, even if the bag looks clean after rinsing. The UK Food Standards Agency advises specific bags for raw meat and fish and separate bags for perishable food that will not be cooked to avoid cross-contamination.”
You could colour code your bags to show what you use them for. And be aware too that storing your reusable bags in the boot of a hot car can help bacteria grow faster.
Keeping it low
According to the Energy Saving Trust, washing clothes at 30C rather than higher temperatures will save around 40 per cent of the energy used each year. But, says Dr Freestone, though laundry detergents might get rid of food and other stains at low temperatures, some microbes might remain.
“A wash at 30C or 40C will not kill bacteria, as most food poisoning pathogens are killed at temperatures above 65C,” she explains. “Using a laundry disinfectant is a good idea as they do kill bacteria and help avoid it building up in the door seals and detergent trays of the washing machine.”
Bacterial load
Washing a full load in the machine, rather than putting on a couple of half loads, saves water and energy. But if you’re running out of socks and end up mixing them with other clothes, bedlinen and tea towels to make up a full load, you risk cross-contamination, transferring bacteria between items.
“If the detergent is antibacterial, and the temperature of the wash is hot – say, 60C – mixing the wash shouldn’t be a problem as the temperature, detergent and disinfectant should kill most microbes, including those in high numbers on tea towels, bath towels and underwear,” says Dr Freestone. “If washing at lower temperatures, more bacteria may remain.”
Using reusables in the kitchen
Many of us have opted to replace single-use kitchen towels and wipes with reusable cloths, but we should be choosy how we use them. “Tea towels and dishcloths are prone to pick up many of the bacteria and fungi they come into contact with,” says Dr Freestone.
“In a scientific study, tea towels were used to wipe down chopping boards used to prepare chicken, which was naturally contaminated with Salmonella – 90 per cent were found to have become contaminated.”
Dr Freestone advises cleaning kitchen cloths and drying them thoroughly after use to avoid spreading germs around your kitchen. And she has a special word of warning about our kitchen sponges. “In another study, I looked at the microbes that were present in kitchen sponges and found they had hundreds of thousands of bacteria and fungal cells in them after a single day of use, which still persisted even after disinfection. I now dispose of my kitchen sponge after a single day’s use.”
Cutting out cling film
Beeswax wraps are a greener -alternative to single-use cling film for things like wrapping sandwiches and covering leftovers. But manufacturer instructions advise they should only be washed in cold water. “Any uncooked food – meat, fish, dairy foods, fruit and vegetables – can contain bacterial and fungal -pathogens, and even cooked foods like chicken can leave behind traces that will become hazardous if not washed off properly” says Dr Freestone.
“Cold water rinsing will remove surface debris, but the water -temperature will not kill bacteria. And the water shear force may not remove all the microorganisms present, as the water resistant nature of the wax surface may even help bacteria to attach better. Store uncooked foods in plastic or glass reusable tub containers with lids on instead. It is easier to sanitise these.”
Second-hand clothes
Buying vintage or second-hand helps support the circular economy. But a study published in the Iranian Journal of Public Health found that, as well as picking up a bargain, you could also risk picking up a microbial infection or fungal skin disease from wearing unwashed items. The same study found that second-hand clothes that had been washed contained no contamination.
Be sure to pop any vintage, used clothing buys in the washing machine before you wear them.
Compost carefully
Composting keeps food peelings and other organic waste, such as coffee grounds, from landfill, helping reduce methane gas emissions and building healthy soil for your garden, too. Unfortunately rats love the warmth of a compost bin to cuddle up in. They can carry the bacteria that can cause Weil’s disease and spread it via their urine. Though the chances of catching the infection are low, it’s best to err on the side of caution and do all you can to keep them out of your compost.
Choose a bin with a solid base and well-fitting lid, or rat-proof an existing bin without a base by placing it on a concrete slab, pebbles or paving stones, so rats can’t dig underneath to get in. Or line it with layers of thick wire mesh with small holes – not chicken wire as they can chew through it. Don’t add cooked food, meat, fish or dairy products and clean out egg shells before adding to the bin as rats are attracted to these leftovers. Keep your composting bin in an area you pass by often, so there’s regular noise and movement around it to put off vermin.
Make-up wake-up
A single reusable cloth make-up remover pad or muslin cloth has the potential to replace hundreds of disposable cotton wool pads or wipes, reducing waste and helping the environment. But ideally, they should be used only once, then washed in the machine on a cycle of at least 40°C.
A quick rinse in the sink isn’t enough to remove the oil, dirt and make-up collected on the wipe. Reusing it without thorough washing can result in bacteria from the wipe being transferred on to your skin, potentially causing breakouts.