Overview
This source page is a mechanical bulk-ingest record for a PDF in the methylmercury infant-formula research pull. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.
Key numbers
The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:
- Alqalam Journal of Medical and Applied Sciences. 2026;9(7):1932-1945
- https://doi.org/10.54361/ajmas.269714
- Marwa Attayeb1 , Aziza Abdelgawad1 , Fauzia Abuhtna1 , Mansor Wafi1 , Awatif Almaqrahi2 , Budour Elmihub1 ,
- Tripoli, Libya. A total of 240 food-contact surface samples were collected from meat, dairy, vegetable, and ready-
- to-eat food facilities. Overall, 151 samples (62.9%) were culture-positive, with the highest positivity observed in
- meat-processing facilities (74.3%) and raw-material handling areas (75.0%). A total of 166 bacterial isolates were
- recovered; Listeria monocytogenes was the most frequent species (19.3%), followed by Staphylococcus aureus
- (18.1%) and Salmonella enterica (16.9%). Strong biofilm formation was detected in 81 isolates (48.8%), particularly
- among Pseudomonas aeruginosa (68.0%) and L. monocytogenes (65.6%). Biofilm-associated isolates showed the
- highest tolerance to QAC-based disinfectants (41.0%), followed by sodium hypochlorite (20.5%), hydrogen
- least one disinfectant (aOR = 4.87), whereas cleaning surfaces at least three times daily reduced this likelihood
- (aOR = 0.42). Enhanced residue removal, biofilm-focused sanitation, and targeted monitoring of high-risk surfaces
- nutrient availability, and the accumulation of organic residues (4–7). Food-contact surfaces manufactured from stainless
- surfaces and forming biofilms under processing-related conditions (4,5). In addition, biofilm-competent environmental
- sanitation when sessile cells are established (8).
- Copyright Author (s) 2026. Distributed under Creative Commons CC-BY 4.0
- Alqalam Journal of Medical and Applied Sciences. 2026;9(7):1932-1945
- https://doi.org/10.54361/ajmas.269714
- temperature, pH, organic load, surface material, and the physiological state of microorganisms (2,9). Studies evaluating
- limiting contact between the active compound and biofilm-associated cells (6,10). An important distinction should be
- efflux mechanisms, and the presence of persister-like subpopulations (5,11).
- with adaptive responses that enhance biofilm formation and survival in L. monocytogenes (12). The complexity of microbial
- programs, equipment design, cleaning frequency, and disinfectant rotation strategies (14,15). Therefore, this study aimed
- A cross-sectional, laboratory-based environmental study was conducted from February to August 2025 in food-processing
- A total of 240 food-contact surface samples were included. The sample size was selected to estimate an anticipated
- as follows: meat-processing facilities (n = 70), dairy-processing facilities (n = 55), vegetable-processing facilities (n = 45),
- and ready-to-eat food-processing facilities (n = 70). A stratified purposive sampling approach was used to ensure
- handling areas (n = 60), cutting or preparation areas (n = 55), washing areas (n = 45), packaging areas (n = 50), and cold-
- storage areas (n = 30). Eligible sites included surfaces directly involved in food preparation, processing, washing, cutting,
- Copyright Author (s) 2026. Distributed under Creative Commons CC-BY 4.0
- Alqalam Journal of Medical and Applied Sciences. 2026;9(7):1932-1945
- https://doi.org/10.54361/ajmas.269714
- conducted according to the principles of ISO 18593:2018 for microbiological sampling of food-chain surfaces (16). On flat
- surfaces, a sterile 10 × 10 cm template was used to delimit a 100 cm² sampling area. The designated area was sampled
- the general requirements of ISO 7218:2024 (17).
- contamination was quantified using the Plate Count Agar method at 30°C, in accordance with ISO 4833-2:2013 (18). Plates
- bacilli, and staphylococci was performed using Analytical Profile Index systems (bioMérieux, France), including API 20E,
- was accepted when the percent identification was ≥90%, and the T index was ≥0.75. Isolates not meeting these criteria
- an approved Salmonella confirmation procedure (19). Presumptive Listeria isolates were identified from colonies recovered
- Stepanović et al. and O’Toole (21,22). Fresh standardized bacterial suspensions were inoculated into sterile flat-bottomed
- 96-well polystyrene microplates containing tryptic soy broth supplemented with 1% glucose. After static incubation for 24
- h, non-adherent cells were removed by gentle washing. Adherent biofilm biomass was fixed, stained with 0.1% crystal
Methods (brief)
- Tripoli, Libya. A total of 240 food-contact surface samples were collected from meat, dairy, vegetable, and ready-
- to-eat food facilities. Overall, 151 samples (62.9%) were culture-positive, with the highest positivity observed in
- processing, and ready-to-eat food facilities. All laboratory procedures, including sample processing, bacterial
- environmental surface samples only; no human participants, patient specimens, animal specimens, or identifiable
- personal data were collected.
- Sample size and sampling strategy
- A total of 240 food-contact surface samples were included. The sample size was selected to estimate an anticipated
- percentage points, while allowing for clustering of samples within facilities. Samples were distributed across facility types
- representation of routine food-contact sites across major processing stages. The sampled sites included raw-material
- Before microbiological sampling, a structured observation form was completed for each sampled surface. Recorded
- surfaces, a sterile 10 × 10 cm template was used to delimit a 100 cm² sampling area. The designated area was sampled
- Each sampling device was transferred into a sterile tube containing neutralizing diluent. Samples were transported in
- insulated containers at 2–8°C and processed within 4 h of collection. Sample handling and laboratory practices followed
- square centimeter (CFU/cm²) and converted to log₁₀ CFU/cm² for statistical analysis. A sample was considered culture-
- applicable institutional laboratory safety procedures. All surface samples and recovered isolates were handled as
- processing facilities. Samples were transported in closed primary containers within leak-resistant secondary containment
- Whitney U test, Kruskal–Wallis test, or Friedman test, with Bonferroni-adjusted post-hoc comparisons where applicable.
- Of the 240 food-contact surface samples collected, 151 (62.9%) were culture-positive. As presented in Table 3, bacterial
Implications
This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.
Wiki pages this source may touch
- Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
- Mixed Meals / Prepared Foods
- Aluminum
Verification notes
- Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing
wiki/sources/pages before creation. - Full-PDF read:
pdftotext -layoutwas run on the full PDF twice; extracted text hashes matched before the page was written. - Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
- Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
- HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.