## 4 Discussion
### Microbiological Analysis  
Some of the reviewed studies refer to a negligible presence of yeast and molds in fresh seaweeds [93; 94; 95]. Similarly, labophilic lactic acid bacteria present in seaweeds do not seem to grow in culture media [96]. Additionally, the microbial load in Marine Agar (heterotrophic marine bacteria) consistently exceeds that of Plate Count Agar, which assesses the total or viable bacterial growth in a sample [32; 33]. Consequently, the focus is placed on evaluating the primary pathogenic agents, at the beginning and end of the test, and determining whether the total microbial load of marine microorganisms throughout the storage time complied with the regulatory parameters outlined by local guidelines in the European Union (EU) (see Supplementary Material, Table S3). For PU, there was a decline in heterotrophic marine bacteria (HMB) over time in the MAP- and VAC-treated seaweeds, whereas in CTRL, the CFUs continued to increase until they surpassed the quantification limit. The treatments appeared to have affected aerobic bacteria, as they continued to grow in the control group, which had approximately 20% oxygen [97]. It is noteworthy that many of the bacteria that inhabit the surface of red marine macroalgae are obligate or facultative aerobe, such as the common _Bacillus_ spp. and _Virgibacillus_ spp. [98; 99]. Numerous seaweeds release secondary metabolites with antimicrobial and antifouling activities--i.e., able to regulate bacterial growth and prevent or inhibit the attachment of unwanted organisms on their surface [93; 100; 101]. This is particularly valid for red seaweeds that, under certain circumstances, can release a variety of compounds with antibiotic activity against Gram-positive and -negative bacteria [102]. Therefore, the treatments must have reduced the total aerobic bacterial load and possibly triggered some metabolic activity in PU with the release of secondary metabolites that affected the microbial population. [PERSON] et al. [76] in their study emphasized the importance of low-temperature storage in minimizing microbial growth. Notably, the authors utilized sterilized Plate Count Agar instead of Marine Agar to assess the Total Aerobic Count (TAC). Their results showed that the initial TAC for fresh _Pyropia yezoensis_ samples was 3.28 log CFU\(\cdot\)g\({}^{-1}\). After 6 days of storage, the TAC for refrigated samples rose to 4.25 log CFU\(\cdot\)g\({}^{-1}\), which was significantly higher compared to samples stored under other conditions such as freezing and supercooling. This study also showed significant growth for the control of _P. yezoensis_ during the storage period, whereas the other treatments exhibited a consistent microbial load, with a slight decrease observed from day 6 onwards. These results are consistent with our findings. For UL, the microbial load remained relatively stable in all treatments throughout the storage days, and neither the MAP nor VAC treatment seemed to have had any significant effect on lowering microbial counts. [PERSON] et al. (2014) studied the microbiology of _Ulva lactuca_ and _Palmaria palmata_ submitted to different washing procedures and stored at 4 \({}^{\circ}\)C for 14 days. The authors noticed that mesophilic aerobes maintained relatively stable levels throughout the storage days, particularly in non-washed and seawater-washed samples of _U. rigida_ and _P. palmata_, for which the initial microbial population ranged from \(10^{3}\) to \(10^{5}\) CFU\(\cdot\)g\({}^{-1}\), in a similar way to what happened in our study to UL. [PERSON] et al. (2010) in a study on the microbial diversity of the seaweeds, observed a decrease in bacterial diversity at the genus and species level for all the seaweeds at the end of the storage period ([PERSON] et al., 2010). In another study from [PERSON] et al. (2010), on the bacterial diversity in dried seaweeds (including _U. lactuca_ and _P. umbilicalis_), a lower bacterial diversity was observed compared to fresh marine macroalgae (specifically, for the case of _U.