Kirkland Signature · Microwave Popcorn
Kirkland Signature Microwave Popcorn 44 Pack Box
Skip until Kirkland discloses microwave bag coating composition.
Microwave popcorn bags typically have grease-resistant coatings that commonly contain PFAS. Kirkland provides no public disclosure of coating chemistry or PFAS status.
The better-graded swap
Quaker
Quaker Butter Popcorn Rice Cakes
70/100 safety
Same rubric that flunked this product. The swap earned Good.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
paper microwave bag with grease-resistant coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What Kirkland Signature Microwave Pack Box is made of, ingredients and materials
Kirkland Signature microwave popcorn bags are paper-based with a grease-resistant coating applied to the interior surface. This coating prevents oil and butter from soaking through during cooking and storage. The composition of that coating is not publicly disclosed by Kirkland; PFAS (PFAS "forever chemicals") are a common choice for grease resistance in food packaging, and Kirkland has not confirmed or ruled out their use in this product. Paper itself poses no chemical hazard, but the coating's identity and migration behavior are unknown to consumers.
What’s concerning
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Grease-resistant coating composition (likely fluorinated)
Kirkland has not disclosed the chemistry of the interior bag coating. PFAS are standard in this application industry-wide; independent testing or brand disclosure is needed to rule out PFAS migration at typical microwave temperatures.
Coating degradation and inhalation risk
If the coating contains Teflon-type coating or other Teflon-family coating, heating may release volatile compounds or particles, especially if the bag is overheated or punctured. No specific testing on Kirkland bags is on record, but this is a recognized hazard class for fluorinated food-contact coatings.
Microplastics
If the coating is a synthetic polymer (including Teflon-family coating), mechanical wear, tearing, or thermal stress during microwaving could release micro- or nanoscale particles into food. No specific evidence for Kirkland bags; this is a category-level concern for unspecified food-contact coatings.
Source, EPA ↗What’s reassuring
Mineral oil or petroleum distillates in ink or adhesive
The external printing and bag sealing may use mineral-based inks or adhesives; no specific contamination or migration hazards have been reported for this product or brand, but food-contact surfaces should be minimized to the interior coating.
BPA & bisphenols
Some paper coatings historically used bisphenol A as a resin component, though this has become less common. Kirkland has not disclosed additives in the paper or coating; no specific BPA recall or report exists for this product.
Source, FDA ↗How is this PFAS grade calculated?
The brand's record and disclosure
Kirkland Signature (Costco's house brand) has not published transparency statements about PFAS use in food-contact packaging as of available records. The brand does not appear on public commitments to phase out PFAS or adopt alternatives. Costco has faced consumer pressure on chemical transparency in recent years, but specific commitments to microwave popcorn bags have not been announced. This silence is the primary red flag; absence of disclosure does not confirm PFAS presence, but it prevents informed choice.
How it compares in its category
Most microwave popcorn bags in the US market use fluorinated grease-barrier coatings, making PFAS presence industry-standard. Some brands (e.g., Orville Redenbacher, Pop Secret, ACT II) also do not publicly disclose coating composition. A small number of manufacturers have committed to PFAS-free alternatives, but these remain niche. Kirkland's lack of differentiation or transparency places it in the mainstream, undisclosed-coating segment of the category.
If you buy it
Follow popcorn bag instructions precisely, do not overheat, and avoid opening the bag immediately after cooking to prevent inhalation of steam (which may carry coating particles or volatilized residues if present). Store unopened boxes in a cool, dry place away from direct heat. Use within the printed expiration date; older bags may have degraded coatings. If you are concerned about PFAS exposure, this product is not a good fit; consider stovetop popcorn in uncoated pots or bulk kernels in paper sacks without internal coatings.
What is not known about PFAS in this product?
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Kirkland Signature has made none
Formulations change between production runs, so check the current label. How we grade.
What are the PFAS-free alternatives to Kirkland Signature Microwave Popcorn 44 Pack Box?
- puffed rice cakes in paperboard packaging
- We found no PFAS statement from the brand
- Mold or bacterial growth in packaging
- paperboard popcorn bag, grease-resistant interior lining
- We found no PFAS statement from the brand
- Moisture and mold risk if bag is compromised
- paper-based food packaging with standard coating
- We found no PFAS statement from the brand
- Ink migration (printing on exterior or interior)
3 hazards checked on this product, all on its full breakdown.
More microwave popcorn grades
How we score, every product runs through the same public 0-100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.