Does pounch tuna/chicken contain BPA in the lining?

December 10, 2009 1:46 PM

Does pounch tuna/chicken contain BPA in the lining?

I know most canned goods use BPA on the inner lining of the can (which can leach into acidic foods), but what about those pouches that tuna comes in?

posted by phrakture to food & drink (10 answers total)

Where are you getting 'cans are lined with material containing BPA?' From five years spent purchasing canned goods I learned that cans were lined with a form of enamel. De-tining can occur in high acid foods that are not rotated properly (tomato products, pineapple juice). Then I spent five years purchasing MREs, which is where the pouch technology comes from. My understanding is that commercial pouch products use a tri-laminate pouch, which is a foil/nylon resin/foil composite. So foil is touching your tuna.
posted by fixedgear at 1:58 PM on December 10, 2009

Where are you getting 'cans are lined with material containing BPA?'

It's been used as a can lining for years. Don't know about pouches.
posted by rtha at 2:06 PM on December 10, 2009

BPA in can lining is well known (sorry, no references at this time. I'm lazy). I discovered this when creating backpacking pots (some people use large beer cans, like Foster's) - BPA leaches out of the lining upon heating. Acid does similar things. If the food is not heated up or acidic, the BPA shouldn't spill out into the food.
posted by phrakture at 2:09 PM on December 10, 2009

Here
posted by phrakture at 2:10 PM on December 10, 2009

I don't have a direct answer, but my impression is that BPA is commonly used to make plastics rigid. Since the plastics used in pouches are pretty well defined by their flexibility, I'd say they are probably free of BPA.
posted by lekvar at 2:31 PM on December 10, 2009

I believe the answer is yes:

"Migration from multi-layer laminated film pouches intended for retort foods was investigated through HPLC analysis with a fluorescence detector, and measurements of residue on evaporation, consumption of potassium permanganate and total organic carbon. HPLC analysis revealed that the levels of migrants in oil and the water which were heated in the pouches (121 degrees C, 30 min) were ten times of those in the corresponding official simulants under the official conditions; n-heptane (25 degrees C, 60 min), and water (95 degrees C, 30 min). Bisphenol A diglycidyl ether and related compounds were found in the oil and the water heated in the pouches, as well as in the simulants. These compounds were thought to have been present in the adhesive between the laminated films, and migrated through the food-contact film of the package. Consumption of potassium permanganate and residue on evaporation of the heated water were ten times of those of the water simulant, while the total organic carbon level of the heated water was several-hold greater than that of the water simulant. In addition, migrant levels per surface area of the pouch were one-fourth of the concentrations per content volume of the pouch. Since compliance with the legal limits is evaluated based on the concentration per surface area, real migration into foods would be underestimated by a factor of another four."

From: Simulation of migration from a multi-layer laminated film intended for retort foods. Uematsu Y et al. Indexed in PubMed.

My understanding is that retort foods are the ready-to-eats in the pouches you describe. It doesn't address tuna specifically, but odds are!
posted by Knowyournuts at 2:37 PM on December 10, 2009

Thanks for the answer. As I suspected, though, it doesn't cause issues unless heated...
posted by phrakture at 2:43 PM on December 10, 2009

Related: this is why I've always been told to avoid canned tomatoes. BPA-lined cans + acidity = leaching (heat not necessary)
posted by jckll at 2:55 PM on December 10, 2009

It looks like my first answer was incorrect, and for that I apologize. However, the heating that they are referring to is the heating that takes place during the retort process. So anything that contains BPA that is in contact with food and which then gets heated (during the retort process) can leach into the food.
posted by fixedgear at 4:06 PM on December 10, 2009

So the heating has already taken place before you buy it? Bummer!
posted by Knowyournuts at 9:39 AM on December 11, 2009