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This question is born more out of sheer laziness than curiosity, but preparing two marinaded meat dishes the other day (Char Su pork and pork vindaloo), it struck me that I could have saved myself a lot of washing up if I marinaded the meat in the plastic packaging they came in.

Would there be any danger of chemicals leaching from the plastic if either a yoghurt or acidic marinade was used? The meat would be stored in the refrigerator for a maximum of 24 hours.

2 Answers 2

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Low and high density polyethylene (PE) and polypropylene (PP) are the two common plastics used in food packaging and food storage containers. Your Ziploc/Rubbermaid etc. containers and bags are chemically identical to most flexible packaging materials used for meat. Polystyrene (PS) in the both the extruded foam and rigid forms is common as well for meat trays.

All are considered chemically compatible and inert to most aqueous food acids:

CP Lab Safety LDPE Chemical Compatibility Chart - https://www.calpaclab.com/ldpe-chemical-compatibility-chart/

CP Lab Safety Polypropylene Chemical Compatibility Chart - https://www.calpaclab.com/polypropylene-chemical-compatibility-chart/

Dutcher PE, PP, PS Compatibility Chart (PDF) - https://www.dutscher.com/data/pdf_guides/en/CCTPPA.pdf

Note that the LDPE table lists 'severe effect' with citric acid, but does not specify concentrations like for acetic acid and shows excellent to good compatibility with fruit juices, cider, and malic acid. The Dutcher chart has fewer entries regarding food and food acids at specific concentrations. All were tested at ambient temperature, so you can expect even less reactivity under refrigeration.

Additives may be used in these plastics (UV protection, antioxidants for stability, plasticizers for flexibility) and should all be rated for food contact. They're typically oil-soluble organic molecules, and generally won't leach into aqueous solutions; however, they may leach into oil-based, high fat, or alcohol-containing marinades.

Pthalates in polyethylene terepthalate (PET) are a plasticizer of concern, though in my experience PET is rarely seen in North America in my region PET is rare other than in specialty beverage bottles and imported Japanese beverages.


References and Further Reading:

Characterization of plastic packaging additives: Food contact, stability and toxicity. Meriem Cherif Lahimer, Naceur Ayed, Jalel Horriche, Sayda Belgaied. https://doi.org/10.1016/j.arabjc.2013.07.022

Food Safety Focus (60th Issue, July 2011) – Incident in Focus: Plasticisers and Food Safety. Melva Chen. https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_60_01.html

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  • Superb answer, thank you @borkymcfood. It is good to know that refrigeration will reduce the miniscule food-safety risk. I am in the UK, and as I understand it any plastics containing PET would be labelled: maxpack.co.uk/2022/01/28/…
    – Greybeard
    Sep 2, 2022 at 10:47
  • Does this also imply that for the kinds of meats vacuum packed like this static01.eu/1prospekte.de/images/uploads/280720/… (just the first example I found; i.e., shrink-wrapped against a carton backing, with a thin plastic sheet on top of the cartonage to make it watertight) could be directly used in lieu of vacuum satchels for sous vide (ignoring the issue of whether it's a good idea to SV without seasoning...)? Or is temperature (i.e. 54°C or whatever) a different matter in this regard?
    – AnoE
    Sep 2, 2022 at 11:36
  • In my evidently different experience, PET (recycle symbol "1") is very common indeed in North American distribution, representing nearly all plastic soda/pop bottles and a wide range of other things, but not usually meat packaging.
    – Ecnerwal
    Sep 2, 2022 at 13:06
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    @AnoE that may not be a good idea - there may be added plasticizers to prevent brittleness under refrigeration, and those may migrate into the meat fat at sous vide temperatures. The thickness and strength won't be the same as FoodSaver bags - they claim they're multiple PE layers laminated with a nylon exterior, and no added plasticizers. Sep 3, 2022 at 0:59
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    @Ecnerwal I stand corrected - it's a regional thing, and in my area both the major soda brands' bottlers have used exclusively blown LDPE. All the beverages brought in from further east are PET. Sep 3, 2022 at 1:06
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I'm not quite clear about what you mean, but food packaging is generally deemed safe. If you are suggesting cutting the bag open, adding a marinade, and refrigerating in the bag within the typical food safety window before cooking, there should not be a problem.

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    Thanks @moscafj, that is exactly what I was asking.
    – Greybeard
    Sep 2, 2022 at 10:38

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