Stainless steel is actually a low carbon, iron based steel which has other metals mixed in to increase its corrosion resistance and strength. It always contains at least 10% chromuim. Other metals can include nickel, manganese, aluminum, silicon, and sulphur. The combination of metals determines the grade of the stainless steel.
Stainless steel does not conduct heat well, so cookware is usually made with an aluminum or copper core. A sheet of aluminum or copper sandwiched between the stainless steel improves the pot’s heating ability.
The aluminum or copper core only becomes an issue if the pot is scratched, grooved, or worn to expose it. If your pot is rusting or if there are signs that the core is wearing through, it is time to replace the pot because it’s probably leaching those metals into your food. Those numbers you see on the bottom of your pot are actually a clue to the grade of stainless steel. These numbers specifically refer to the amount of chromium and nickel blended into the stainless steel. For example, the numbers 18/10 show that the pot is comprised of 18% chromium, and 10% nickel.
The grade of stainless steel identifies how corrosive it is. 18/8 and 18/10 indicate that the pot is part of the 300 series of stainless steel. With a higher amount of nickel, the 300 series is more resistant to corrosion and rust. A pot stamped 18/0 is part of the 400 series. With less nickel, these pots are more vulnerable to corrosion; they are also magnetic. 200 series stainless steel is considered low quality and made with manganese instead of nickel.
When shopping for stainless steel cookware, try to avoid the 200 series. It corrodes easily, is not durable, and contains manganese which can be extremely toxic. The 300 series is the most common and the considered the most durable. It is also highest in nickel.
Good quality stainless steel cookware, for example, All Clad, is a very safe choice for your cooking needs. There is little to no negative research on the affects of stainless steel and unsafe cooking.
Teflon® is a brand name for a man-made chemical know as polyetrafluoroethylene (PTFE), a highly useful plastic material in a class know as pluoropolymers. It has been around since the 1940s. PTFE has a wide variety of uses because it is extremely stable and can provide an almost frictionless surface.It has been used to infuse stain resistance to fabrics, carpets, weather-proofing outdoor signs, wall coverings and what is is most popular for is the non-stick coating surface for pans and other cookware.
Perfluorooctanic acid (PFOA), also know as C8, is another man-made chemical used in the process of making Teflon® and similar chemicals (known as flourotelomers). PFOA has been classified by the US EPA as a persistent organic pollutant and it is classed as a “likely carcinogen”. PFOA has the potential to be a real health concern because it can stay in the human body and the environment for long periods of time. Studies have found that PFOA is present in up to 98% of Americans.
Higher levels have been found in the blood of community residents where local water supplies have been contaminated by PFOA. People exposed in the workplace can have levels many thousand times higher than your average American. Presence of this toxic substance has been reported in conditions that include impaired thyroid hormone function, liver enlargement, endocrine disorders, cardiovascular disorders, hypo-lipidemia and immune system disorders.
According to tests commissioned by the Environmental Working Group (EWG) Teflon® surfaces for cookware and non-stick surfaces can exceed temperatures at which the coating breaks apart and emits toxic particles and fumes. These fumes can cause flu-like symptoms in humans (a condition known as polymer fume fever) and can be fatal to birds.
For the past fifty years DuPont has claimed that their Teflon® coatings do not emit hazardous chemicals through normal use. In a recent press release, DuPont wrote that “significant decomposition of the coating will occur only when temperatures exceed about 660 degrees F (340 degrees C). These temperatures alone are well above the normal cooking range.” On the contrary, tests show that Teflon® cookware exceeds these temperatures and turns toxic through the common act of preheating a pan, on a burner set on high.
In tests conducted in May 2003 by a University Food Safety professor, a generic non-stick frying pan preheated on a conventional, electric stovetop burner reached 736°F in three minutes and 20 seconds, with temperatures still rising when the tests were terminated. A Teflon® pan reached 721°F in just five minutes under the same test conditions, as measured by a commercially available infrared thermometer. DuPont studies show that the Teflon® offgases toxic particulates at 464°F. At 680°F Teflon® pans release at least six toxic gases, including two carcinogens, two global pollutants, and MFA, a chemical lethal to humans at low doses.
In view of results from various animal and human studies, traditional non-stick coating manufactures have been prompted under an EPA stewardship program to phase out PFOA from their products by the year 2015 and reduce emissions to zero.
The good news is there are safe alternatives to out there, cast iron, stainless steel, and new ceramic coatings that are PTFE and PFOA free.
