Red blood cell (rbc)

For microbiological enumeration, a representative sample (10 g) was transferred to a sterile stomacher bag with 90 mL sterilized Ringer solution (Merck, Darmstadt, Germany) and was homogenized for 60 s with a Stomacher (Bag Mixer, Interscience, Saint Nom la Bretêche, France). Samples (0.1 mL) of 10-fold serial dilutions of homogenates were spread on the surface of Rose Bengal Chloramhenicol (RBC, Merck, Darmstadt, Germany) for enumeration of yeasts and molds after incubation at 25 °C for 120 h. Total aerobic viable count (TVC) was enumerated on plate count agar (PCA, Merck, Darmstadt, Germany) after incubation at 25 °C for 72 h. Two replicates of at least three appropriate dilutions were enumerated. The microbial growth was then described using the Baranyi growth model. For curve fitting, the program DMFit was used (available at http://www.combase.cc/index.php/en/ (accessed on 24 July 2023)). The kinetic parameters, microbial growth rate (k in d⁻¹), and lag phase (λ in d) were estimated.

Calcium acetate monohydrate [(CH₃COO)₂Ca·H₂O], diammonium hydrogen phosphate [(NH₄)₂HPO₄], and phosphate buffered saline (PBS)(−) were obtained from FUJIFILM Wako Pure Chemical Co. (Osaka, Japan). αPLys [molecular weight (Mw) = 15,000–30,000 g/mol], αpArg (MW = 15,000–70,000 g/mol). FITC–BSA, BSA, RBC, and a LIVE/DEAD double staining kit were purchased from Merck KGaA (Darmstadt, Germany). ε-PLys with a Mw of 4000 g/mol was gifted by JNC Co., (Tokyo, Japan). A calcium colorimetric assay kit was obtained from Metallogenics Co. (Chiba, Japan). Minimum essential alpha medium (α-MEM), fetal bovine serum (FBS), penicillin–streptomycin solution (×100), trypsin/ethylenediaminetetraacetic acid (EDTA) solution, and rhodamine–phalloidin were obtained from Thermo Fisher Scientific Inc. (Waltham, MA, USA). All reagents were of analytical grade and were used without further purification.