Is It Safe to Use Aluminum Foil in Cooking?

The aim of the work was to estimate the degree of aluminum leakage from aluminum foil roll during baking process of selected food/meals. The experiment included 11 different types of food (Atlantic salmon Salmo salar, mackerel Scomber scombrus, duck breasts, cheese Hermelín, tomato, paprika, Carlsbad dumplings, pork roast, pork neck, chicken breasts, and chicken thighs) baked both marinated and not marinated. The aluminum content was measured by AAS and ICP/MS methods. The highest aluminum increase was observed in the samples of marinated Salmo salar (41.86 ± 0.56 mg/kg), Scomber scombrus (49.34 ± 0.44 mg/kg), and duck breast (117.26 ± 1.37 g/kg). The research was also supported by the survey that consisted of 784 respondents with different sociodemographic characteristics. The study clearly showed the occurrence of aluminum contamination of food when it is prepared by baking in aluminum foil. It cannot be concluded that aluminum leakage will occur with each type of food. The aluminum contents found among investigated samples are not alarming, though the increase was measured up to 40 times. On the other hand, revealed aluminum contents can represent a risk for younger/smaller children and for individuals with diagnosed certain ailments.

If you’re baking fish, roasting vegetables or preparing a piece of meat for dinner tonight, chances are that you’ll wrap your food in aluminium foil. What you may not realise is that some of the foil will leach into your meal – and this could be bad for your health.

Research that I conducted with a group of colleagues has explored the use of aluminium for cooking and preparing food. Aluminium doesn’t just appear in foil: it is the most popular cookware material used by people in developing countries. Pots and pans are lined with it and it is found in some kitchen utensils like large serving spoons. Copper used to fulfil this role, but over time it’s been replaced by aluminium because it is cheaper to mass produce and easier to clean.

But while cooking your food in aluminium pots or pans isn’t a bad thing, placing it in foil and putting it in the oven is problematic. This is especially true with acidic or spicy food that’s prepared at high temperatures.

Aluminium and health

Human bodies can excrete small amounts of aluminium very efficiently. This means that minimal exposure to aluminium is not a problem: the World Health Organisation has established a safe daily intake of 40mg per kilogram of body weight per day. So for a person who weighs 60kg the allowable intake would be 2400 mg.

But most people are exposed to and ingest far more than this suggested safe daily intake. Aluminium is present in corn, yellow cheese, salt, herbs, spices and tea. It’s used in cooking utensils, as described above, as well as in pharmacological agents like antacids and antiperspirants. Aluminium sulfate, which is derived from aluminium, is used as a coagulant during the purification process of drinking water.

Scientists are exploring whether over-exposure to aluminium may be posing threats to human health. For instance, high concentrations of aluminium have been detected in the brain tissue of patients with Alzheimer’s disease. Scientists have examined the community of old people with Alzheimer’s and concluded that it is a modern disease that’s developed from altered living conditions associated with society’s industrialisation. These conditions may include high levels of aluminium in daily life.

Aluminium poses other health risks, too. Studies have suggested that high aluminium intake may be harmful to some patients with bone diseases or renal impairment. It also reduces the growth rate of human brain cells.

Avoid foil when cooking

Given all of these proven risks, it’s important to determine the aluminium concentration when cooking. Pots and other cookware tend to be oxidised, providing an inert layer that prevents the aluminium from leaching into food. The problem is that when you scrub your pots after cooking, that layer is worn away and the aluminium can seep into your food. This is easily avoided: when you get new aluminium pots, boil water in them several times until the base becomes matt. This creates a natural oxidation that prevents leaching. They may look nicer when they’re scrubbed and shiny, but a matt base is better for your food and your health.

But cooking your food in foil is a different story. Aluminium foil is disposable and you will not be able to create that inert layer prior to using it. My research found that the migration of aluminium into food during the cooking process of food wrapped in aluminium foil is above the permissible limit set by the World Health Organisation.

Aluminium is significantly more likely to leach into food, and at higher levels, in acidic and liquid food solutions like lemon and tomato juice than in those containing alcohol or salt. Leaching levels climb even more when spice is added to food that’s cooked in aluminium foil. Anything acidic sparks a particularly aggressive process that dissolves layers of aluminium into food.

This research suggests that aluminium foil should not be used for cooking. Instead, we’d recommend using glassware or porcelain when preparing baked dishes. It’s safe to wrap cold food in foil, though not for long stretches of time because food has a shelf life and because aluminium in the foil will begin to leach into the food depending on ingredients like spices.

Americans have been using non-stick aluminum foil roll for over 100 years, since it was first used to wrap Life Savers, candy bars, and gum. For many years up to today, we’ve mostly used it in our kitchens, to bake fish or roast vegetables on the barbecue, to line baking pans, and to trap steam when cooking.

And experts have expressed concern about just how much of it we’re using, with studies even warning that it could have some seriously harmful health effects. Do those warnings have any merit? For more facts about household aluminum foil, here’s why it has a shiny and a dull side.

Potential dangers of aluminum foil

According to research, some of the foil used in cooking, baking, and grilling leaches into your food, which can pose health problems over time. Scientists have been looking at the potential threat that overexposure to aluminum may have on human health for years. For example, researchers have found high concentrations of aluminum in the brain tissue of patients with Alzheimer’s disease. Studies have also found that high aluminum intake may be linked to a reduction in the growth rate of human cells, and may be potentially harmful for patients with bone diseases or renal impairment.

It depends on the food and the temperature

Research has generally found that a couple of factors make aluminum more likely to leach into your food. One of these is the temperature: The higher the temperature you’re cooking at, the more conducive the environment is for aluminum to enter your food, an Electrochem. Sci. study found.

Aluminum foil is a thin-rolled sheet of alloyed aluminum varying in thickness from about 4–150 μm. It was first produced commercially in the US in 1913 where it was used for wrapping Life Savers™, candy bars and chewing gum. In 1921, it was laminated on paperboard to produce coated folding cartons. Household foil was marketed in the late 1920s, and the first heat-sealable foil was developed in 1938. Formed or semirigid containers appeared on the market in 1949. Today foil has been replaced in many applications by metalized films.

Aluminium foil is widely used to seal yoghurt containers (e.g. plastic cups) and owing to the acidic nature of yoghurt and the necessity of heat sealing, the aluminium foil is normally coated with a layer of plastic. If the preformed type of plastic cup is used, the aluminium foil lids are usually precut and around 2500–3000 lids are packed into a special magazine to minimise mechanical damage. The diameter of these lids is 100 mm, and they usually have a pull-tab for easy opening.

The gauge of the foil is around 40 μm, and each lid is normally embossed. The embossing pattern can be varied to suit the customer's requirements and the impression can be up to 100 μm in depth. The embossing is essential to facilitate easy pickup of single lids from the magazine assembly prior to placing over the filled cup and heat sealing.

For yoghurt packaged using the form-fill-seal technique, the aluminium foil is delivered to the dairy as a reel, with the width of the reel being varied in relation to the number of filling heads (abreast) on the packaging machine. The aluminium foil (gauge around 40 μm) is similar to that of the precut type, but the embossing process is omitted since it would serve no function.

Shielding is achieved by incorporating restaurant aluminum foil (typically 0.02–0.03 mm thick), as part of the container. For example, for a frozen meal in a multicompartment tray, it is possible to place ice cream in a totally shielded compartment of the tray—surrounded by aluminum foil—and keep it frozen while the rest of the frozen meal is heated by microwaves. It is also possible to place aluminum foil around portions of the tray to prevent overheating of the corners, sides, or edges of the food.

While the use of shields was originally accomplished by adhering aluminum patches to the surface of trays, a company in the Netherlands, Shieltronics, B.V., has developed a patented procedure that embeds the aluminum within the polyethylene or other plastic tray. In this way, the amount of microwave energy applied to a food component or components will be optimized to provide the optimal temperature for that component. For example, it would be possible to heat a protein, such as fish, with a vegetable, such as potato, and a salad at the same time, with the salad surrounded by the aluminum so it remains cold, while the microwaves are heating the other components.

Overlaying the packages means use of aluminium foil to plastic film or paper to enhance obstruction properties. The application is encouraged by thin checks. Even if plastic covers empower warm sealability, it does not mean that the seal will totally bar dampness and air. Because aluminum packages are more expensive, they are frequently used to package high esteem foods, like: dried soups, herbs, or flavors. A less expensive option to overlaid packaging is metallized film. Metallized films are made of plastic, covered with a thin layer of aluminum metal (Fellows and Axtell, 2002). These films have improved hindrance properties to dampness, oils, scents, and air, the intelligent surface of the aluminum being appreciated by customers. More adaptable than overlaid films, metallized films are basically used to package snacks. Taking into account that the individual components of covers and metallized films are recyclable, from the financial point of view, the worry lies in arranging and isolating the material blocks for reuse.

Meat can be wrapped tightly in professional foil to retain steam as effectively as a covered pan. Bramblett et al., (1959) compared two oven temperatures, 63 and 68°C, for heating of foil-wrapped muscles from beef round. The lower temperature produced the more tender, juicy meat. Beef roasts cooked in foil may have a steamed flavor (Blaker et al., 1959). Baity et al., (1969) reported that at a low oven temperature (93°C), beef loaves cooked more rapidly when foil was tightly sealed than when the loaves were not wrapped or loosely wrapped. At a higher temperature (232°C), cooking times increased with foil wraps. Quality attributes of the loaves were not discussed.

Polyester cooking films and bags are also available for use in the heating of meat. Results of studies of the quality of meat prepared in these films and bags suggest that the quality is comparable to that of meat heated in foil. Beef top round roasts heated in bags to 80°C in ovens at 177 and 205°C took less time but had greater cooking losses than the roasts heated similarly but without bags (Shaffer et al., 1973).