Review Papers Claim by Claim

Figure A — Relative study depth across flour types (synthesis of review statements)

Note: heights are a conservative synthesis index derived from the review's repeated emphasis: wheat & rye = best-studied; spelt moderate; many alternative flours (teff, quinoa, amaranth, chia, legumes) have sparse data — see review text Holubchyk et al. — flour coverage

Figure B — Dominant LAB and yeast taxa (presence across tables)

These indices reflect the paper's compiled tables and frequency statements (S. cerevisiae and Lpb. plantarum are repeatedly listed across many sourdoughs). For primary data and extensive species lists see the review Holubchyk et al. — taxa tables

1) Strengths

• Comprehensive species-level compilation across many published culture-dependent and -independent studies; practical tables are useful for starter/strain selection (Holubchyk et al. tables).
• Balanced emphasis on strain-specific probiotic phenotypes (resistance to pH/bile, aggregation, antimicrobial/antifungal activity) and on safety considerations (antibiotic resistance in Enterococcus), reflecting current best-practice criteria for probiotic qualification (Probiotic qualification criteria).

2) Limitations & blindspots

• Heterogeneous source studies: the review necessarily aggregates work using diverse methods (culture-based, 16S/ITS amplicon, metagenomics) without formally weighting methodological biases; this reduces ability to compare frequencies quantitatively (authors note this) Holubchyk et al. — limitation note.
• Evidence-level: much of the probiotic evidence cited is in vitro (acid/bile survival, agar antagonism); in vitro probiotic traits are necessary but insufficient to claim health benefit — clinical validation is lacking (D).
• Antibiotic resistance & safety: authors flag Enterococcus faecium concerns but the review could have more systematically presented ARG screening data and horizontal transfer risk for candidate strains (genomic data are increasingly available; e.g., BSH and ARG screens in recent sourdough strains) — a formal safety table would strengthen practical use.
• Origin and ecology unresolved: the review records conflicting studies on source attribution (grain/water/bakers/environment) but does not attempt meta-analytic reconciliation; Landis et al. also showed processing/flour > geography, reinforcing the need for controlled sampling and metadata standards (Landis et al. — driver analysis).

3) Reproducibility & transparency

As a narrative review, reproducibility depends on cited primary studies. The authors provide many references and tables but do not supply a machine-readable dataset or PRISMA-style flow for literature selection; adding a supplement with the raw citation list, criteria, and an Excel/CSV table (strain, source, methods, assays, outcome) would materially improve reproducibility and re-use.

4) Recommendations to strengthen future versions

1. Provide a PRISMA-like search flow and an open CSV of the extracted strain-level data (source, method, in vitro tests, genomic/ARG screens, phenotypes).
2. Include a safety table summarising known ARGs/virulence markers for candidate probiotic strains (Enterococcus and non-Enterococcus separate), and note whether ARGs are plasmid-associated.
3. Quantify confidence per entry (e.g., culture-only = low confidence; 16S-only = ambiguous species-level; WGS = high confidence).
4. Propose standardized in vitro pipelines (survival assays, adhesion models, co-culture antagonism panels) and minimal genomic screens for probiotic candidacy (WGS + ARG screen + plasmid detection + virulence factors).