It has just occurred to me that I know a lot about plastics and food storage, since I began researching the topic when my now 15 yo daughter did a science fair project back when she was in the 5th grade.
There is a lot of mis-information out there regarding what is safe vs. unsafe and why.
So I'll start at the beginning
"Food safe" plastics are made in molds with different release chemicals than plastics made for other storage purposes. Never store food in buckets not labeled "food safe", in Rubbermaid/Sterilite type bins or in plastic garbage bin without a barrier (such as a foil-Mylar bag) between the actual food and the plastic container. Never store food in any type of bag intended/manufactured for disposal of garbage or plastic wrap such as the type used to hold things together for shipping--these bags/films are not food safe for many reasons, including the addition of deodorizing and uv stabilization ingredients. Ensure that your plastic wrap, zip-top bags, and other food-storage bags (such as bread bags and fold-top sandwich bags) are made by a reputable manufacturer so that you can be sure they are made of polypropylene and don't contain additives such as lead.
Most plastics produced today are labelled with a number:
In short terms, look for plastic labelled with numbers 1, 2, 4, and 5 for safety. My family sticks with 2, 4, and 5 for any plastic items we do buy, and we generally only store our food in glass or Pyrex, or stainless steel containers (except for a few Tupperware freezer containers). We invested in stainless steel water bottles 5 years ago, and despite a couple of dents from being dropped they are still in great condition.
Tupperware and Rubbermaid brand food storage containers, as well as the more "disposable" Gladware and Ziploc plastic containers are generally made of #5 PP Polypropylene so are considered pretty safe.
Microwaveable containers and re-fillable 5 gallon water-cooler bottles are often made of a Lexan-type #7 PC Polycarbonate plastic and are NOT considered safe in Canada by our government because PC Polycarbonate contains Bisphenol-A BPA (along with PC Polycarbonate baby bottles and PC Polycarbonate water bottles such as those that were made by Nalgene until recently). BPA is dangerous because it is an "endocrine-disruptor" and acts like synthetic estrogen in the human body and has also been found to be carcinogenic.
Some cheaper types of plastic wrap (some of the really BIG rolls) are made of #3 PVC Polyvinyl Chloride and are dangerous to human health (along with many cheap "rubber ducky" type plastic toys and baby blocks) because they contain pthalates which are "endocrine-disruptors" which act like synthetic estrogen in the human body and have also been found to be carcinogenic.
BPA and pthalates are two of the more dangerous components of the "unsafe" plastics, but as you can see from the information quoted above there are other plastics constituents that are questionable. Watch labeling, because often these days plastics that have never contained BPA are labeled "BPA free" because it's a buzz-word phrase these days. If you avoid the unsafe plastics, you never need to worry about BPA.
As an aside, if you are into scrapbooking or caring for photographs and other memorabilia you will often find that photo albums are labeled as "acid free" but that the labeling with ignore the fact that this term only refers to paper products and adhesives (paper and adhesives that contain, often natural, acids cause paper/photos to yellow prematurely). If you want to keep your photos and memorabilia safe from degradation, ensure that the plastics used for storing important photos and memorabilia are polypropylene, mylar (not the metalized stuff obviously) and polyester. PVC plastic damages photos and paper memorabilia by leaching plasticizers/oily substances.
There is a lot of mis-information out there regarding what is safe vs. unsafe and why.
So I'll start at the beginning
"Food safe" plastics are made in molds with different release chemicals than plastics made for other storage purposes. Never store food in buckets not labeled "food safe", in Rubbermaid/Sterilite type bins or in plastic garbage bin without a barrier (such as a foil-Mylar bag) between the actual food and the plastic container. Never store food in any type of bag intended/manufactured for disposal of garbage or plastic wrap such as the type used to hold things together for shipping--these bags/films are not food safe for many reasons, including the addition of deodorizing and uv stabilization ingredients. Ensure that your plastic wrap, zip-top bags, and other food-storage bags (such as bread bags and fold-top sandwich bags) are made by a reputable manufacturer so that you can be sure they are made of polypropylene and don't contain additives such as lead.
Most plastics produced today are labelled with a number:
That's a long read, but it's very important information to be aware of.from http://lifewithoutplastic.com/index.php?option=com_content&view=article&id=67&Itemid=73&lang=en
The seven plastic resin codes are each briefly described below to provide a quick snapshot detailing the name of the resin (i.e., the base material of the plastic), typical products it is found in, dangerous chemicals it leaches, and why they are dangerous.
#1 Polyethylene terephthalate (PET or PETE) Used in soft drink, juice, water, beer, mouthwash, peanut butter, salad dressing, detergent and cleaner containers. May leach antimony trioxide. Workers exposed to antimony trioxide for long periods of time have exhibited respiratory and skin irritation; among female workers, increased incidence of menstrual problems and miscarriage; their children exhibited slower development in the first twelve months of life. The longer a liquid is left in such a container the greater the potential for release of antimony into the liquid. Considered a relatively safe plastic. Our research on risks associated with this type of plastic is ongoing.
#2 High density polyethylene (HDPE) Used in opaque milk, water, and juice containers, bleach, detergent and shampoo bottles, garbage bags, yogurt and margarine tubs, cereal box liners. Considered a 'safer' plastic. Our research on risks associated with this type of plastic is ongoing.
#3 Polyvinyl chloride (V or Vinyl or PVC) Used in toys, clear food and non-food packaging (e.g., cling wrap), some squeeze bottles, shampoo bottles, cooking oil and peanut butter jars, detergent and window cleaner bottles, shower curtains, medical tubing, and numerous construction products (e.g., pipes, siding). PVC has been described as one of the most hazardous consumer products ever created. Leaches di(2-ethylhexyl) phthalate (DEHP) or butyl benzyl phthalate (BBzP), depending on which is used as the plasticizer or softener (usually DEHP). DEHP and BBzP are endocrine disruptors mimicking the female hormone estrogen; have been strongly linked to asthma and allergic symptoms in children; may cause certain types of cancer; linked to negative effects on the liver, kidney, spleen, bone formation and body weight. In Europe, DEHP and BBzP and other dangerous pthalates have been banned from use in plastic toys for children under three since 1999. Not so elsewhere, including Canada and the United States.
#4 Low density polyethylene (LDPE) Used in grocery store, dry cleaning, bread and frozen food bags, most plastic wraps, squeezable bottles (honey, mustard). Considered a 'safer' plastic. Our research on risks associated with this type of plastic is ongoing.
#5 Polypropylene (PP) Used in ketchup bottles, yogurt and margarine tubs, medecine and syrup bottles, straws, Rubbermaid and other opaque plastic containers, including baby bottles. Considered a 'safer' plastic. Our research on risks associated with this type of plastic is ongoing.
#6 Polystyrene (PS) Used in Styrofoam containers, egg cartons, disposable cups and bowls, take-out food containers, plastic cutlery, compact disc cases. Leaches styrene, which is an endocrine disruptor mimicking the female hormone estrogen, and thus has the potential to cause reproductive and developmental problems; long-term exposure by workers has shown brain and nervous system effects; adverse effects on red blood cells, liver, kidneys and stomach in animal studies. Also present in secondhand cigarette smoke, off-gassing of building materials, car exhaust and possibly drinking water. Styrene migrates significantly from polystyrene containers into the container's contents when oily foods are heated in such containers.
#7 Other This is a catch-all category that includes anything that does not come within the other six categories. As such, one must be careful in interpreting this category because it includes polycarbonate - a dangerous plastic - but it also includes the new, safer, biodegradable bio-based plastics made from renewable resources such as corn and potato starch, and sugar cane. Polycarbonate is used in many plastic baby bottles, clear plastic sippy cups, sports water bottles, three and five gallon large water storage containers, metal food can liners, some juice and ketchup containers, compact discs, cell phones, computers. Polycarbonate leaches Bisphenol A (some effects described above), and numerous studies have indicated a wide array of possible adverse effects from low-level exposure to Bisphenol A: chromosome damage in female ovaries, decreased sperm production in males, early onset of puberty, various behavioural changes, altered immune function, and sex reversal in frogs.
Important Note: Two other types of plastic that fall under code 7 are acrylonitrile styrene (AS) or styrene acrylonitrile (SAN), and acrylonitrile butadiene styrene (ABS). Both AS/SAN and ABS are higher quality plastics with increased strength, rigidity, toughness and temperature and chemical resistance. AS/SAN is used in mixing bowls, thermos casing, dishes, cutlery, coffee filters, toothbrushes, outer covers (printers, calculators, lamps), battery housing. The incorporation of butadiene during the manufacture of AS/SAN, produces ABS, which is an even tougher plastic. ABS is used in LEGO toys, pipes, golf club heads, automotive parts, protective head gear. Our research on risks associated with AS/SAN and ABS is ongoing.
In short terms, look for plastic labelled with numbers 1, 2, 4, and 5 for safety. My family sticks with 2, 4, and 5 for any plastic items we do buy, and we generally only store our food in glass or Pyrex, or stainless steel containers (except for a few Tupperware freezer containers). We invested in stainless steel water bottles 5 years ago, and despite a couple of dents from being dropped they are still in great condition.
Tupperware and Rubbermaid brand food storage containers, as well as the more "disposable" Gladware and Ziploc plastic containers are generally made of #5 PP Polypropylene so are considered pretty safe.
Microwaveable containers and re-fillable 5 gallon water-cooler bottles are often made of a Lexan-type #7 PC Polycarbonate plastic and are NOT considered safe in Canada by our government because PC Polycarbonate contains Bisphenol-A BPA (along with PC Polycarbonate baby bottles and PC Polycarbonate water bottles such as those that were made by Nalgene until recently). BPA is dangerous because it is an "endocrine-disruptor" and acts like synthetic estrogen in the human body and has also been found to be carcinogenic.
Some cheaper types of plastic wrap (some of the really BIG rolls) are made of #3 PVC Polyvinyl Chloride and are dangerous to human health (along with many cheap "rubber ducky" type plastic toys and baby blocks) because they contain pthalates which are "endocrine-disruptors" which act like synthetic estrogen in the human body and have also been found to be carcinogenic.
BPA and pthalates are two of the more dangerous components of the "unsafe" plastics, but as you can see from the information quoted above there are other plastics constituents that are questionable. Watch labeling, because often these days plastics that have never contained BPA are labeled "BPA free" because it's a buzz-word phrase these days. If you avoid the unsafe plastics, you never need to worry about BPA.
As an aside, if you are into scrapbooking or caring for photographs and other memorabilia you will often find that photo albums are labeled as "acid free" but that the labeling with ignore the fact that this term only refers to paper products and adhesives (paper and adhesives that contain, often natural, acids cause paper/photos to yellow prematurely). If you want to keep your photos and memorabilia safe from degradation, ensure that the plastics used for storing important photos and memorabilia are polypropylene, mylar (not the metalized stuff obviously) and polyester. PVC plastic damages photos and paper memorabilia by leaching plasticizers/oily substances.