Then, the burgers were placed on 137 × 187 × 50 mm trays made from polyethylene terephthalate (PET) with an absorbent pad (absorbency 1700 mL/m2). The trays were then sealed with 35 µm thick PSF films (PSF35ZAC, PolTechPack, Olstzn, Poland). Burgers were packed in modified ...