One woman i know had a temporary bout of poisoning from using a teflon coated baking pan roasting a chicken, i assume that the pan got overheated by the oven elements radiating onto it. grilling on teflon coated pans would also have this problem. baking cakes etc may be ok because the cake covers all the teflon area giving even heat distribution. also in this case the teflon was old and starting to flake, if the teflon gets crumbly or starts to flake the pan should be replaced.
the toxicity problems are with PFOA or perfluorooctanoic acid which is used to make teflon, however the teflon itself is inert unless heated above 450F/230C when it gases PFOA
personally i am wary of the temperature getting above 320F/160C, a reasonable temperature for shallow pan frying is 266F/130C
the usa non-stick manufacturers including dupont have committed to reduce PFOA emissions by 95% by 2010
my sister struggled for years with a stainless steel frying pan, couldn't believe the difference when i brought her a heavy gauge aluminium one with a teflon coating.
HEAVY GAUGE aluminium frypans last a lot longer as the heat distributes more evenly avoiding hot spots degrading the teflon.
small scratches in the teflon don't really matter because the amount of aluminium absorbed that way is low compared to whats in food anyway.
howver if you are cooking or heating something acid then bare aluminium becomes more of an issue
18/10 which is the high lustre stainless steel is 18%chromium, 10% nickel, nickel absorbtion from stainless steel cookware can apparently be a problem for children with poor metals elimination, doesn't pay to scrub stainless steel too much, put up with a certain level of staining so to speak. freshly abraded stainless steel may well leach more. the stainless forms an oxide coating, best left as undisturbed as possible.
i think there are big quality differences between stainless steel manufacturer's. like my tefal stainless steel pressure cookers use inox which is a european standard and seems ok but some pots that have a non descript 18/10 seems to have leaching or some sort of reactivity issues that degrade the food being cooked. teflon in good condition is the least reactive and most superior cooking surface imo.
stainless steel is, like all metals, reactive and can have a degrading effect on food quality in cooking and storage
its also a very poor conductor of heat which is why they put aluminium or copper heat spreaders in stainless steel pots and pressure cookers
from a yahoo autismandenzymes post "metallic taste with water warmed in a stainless steel pot"
"as i have gone microwaveless (not even happy to use the microwave for warming water as it is a very high magnetic field generator from the transformer)
needed to sort out warming drinking water (is mid winter, had to lag some outside water pipes to stop stop them freezing in the frosts.........but beautiful clear days and lovely sky colours on dawn and sunset......)
so bought a cheap chinese stainless steel small pot to warm the water in on gas......
now a bright shinly pot, not at all dulled like my stainless pressure cooker, but when i warmed water the water in it, the water had a metallic taste, which may have been some combination of nickel, chromium and iron, the nickel i would worrry about as i saw an a-m post where a child had high nickel levels from food cooked in stainless steel cookware.
now knowing a bit about metals surfaces and oxides i surmised that stainless steel needs an oxide surface to seal it so what i did was boil some water in the pot for a while and then warm some drinking water again and presto! no metallic taste.
now the relevance of this is, if you have stainless steel cookware you need to not break that surface oxide when cleaning which means don't scour and just use a plastic bristle brush if that. LEAVE stains in and don't try to clean them out, that is just some pigmentation in the oxide layer and a good sign.
you will get the hang of what to remove and what not after a while, any raised food particles i remove, but if it is colour going into the oxide layer i leave it. that oxide layer is what seals the reactive metals surface with concomittant leaching away from the cooking food.
the manufacturers also say something like this, but don't tell you why. naughty manufacturers.
i would surmise that the mother with the child with high nickel levels was too vigorous a cleaner with her stainless steel cookware. its the same with cast iron pots, they get a sealing patina important to keeping the reactive iron out of the food.
there's a good theoretical reason for there being a problem with microwave cooking, at the photon level where photons inject energy into the food, conduction cooking is very broad, chaotic and random, but microwave cooking is very narrow ranging and potentially chemically resonant with some of the food molecules and altering them
they could design microwaves to cook much more like conduction cooking, 50 years away? (2058, if i make it that far ;o)
for making a feral broth , i use a blackish romanian (not chinese!) made enameled stock pot, hopefully there's no leaching toxic metals from the enamel, don't go for fancy colours, they are far more likely to have toxic metals in.
i just use the oven and put some aluminium foil over the hot air vent of the oven to keep the heat in so that its economic and very gently simmer the broth for about 19? hours
i emailed (june 2006) ardena gifts about the stockpots they sell (which i use - australia) :
“i have one of your self basting roasters which i am very pleased with as it offers several advantages over stainless steel.
Do you know if there is any lead in the vitrious enamel coating/glaze?
There appears to be an issue with lead in glazes of chinese manufature in dinner tableware, wether there is a similar issue in the vitreous enamel coatings of cookware I do not know
“We understand your concern as lead is used in porcelain enamel colourants, particularly red/orange. Our products, unlike the Chinese, are subjected to strict lead cadmium tests and are divided into two groups - exterior colours and interior colours. Interior colours are free of lead cadmium and safe for any cooking use. Exterior colours may contain lead but these surfaces do not come into contact with food.
All the internal/cooking surfaces of our products are lead-free.”
digital temperature thermometer's are not expensive and good value, i use one all the time for pasturization temperatures and checking cooling in the bacterial growth danger zones
one of the traps of low temperature cooking is if you say want to cook at a temperature of 78C/172F, that it doesn't swing down below about 65C/149F, some bacteria can be active at a suprisingly high temperture
basically i just steam, pan fry, pressure cook or casserole
food being cooked has a temperature gradient through it, like say a roast, so provided you think in terms of that gradient you can get much the same effect as low temperature cooking, even with veges if you not boiling but steaming or pressure cooking
the temperature is held down internally by the conversion of the food molecules to other forms and as it gets converted the temperature rises
i think i use 250F/121C as a slow roasting temperature