Antimicrobial and produce-wash data for extracts of Piper guineense, Xylopia aethiopica, Monodora myristica and Tetrapleura tetraptera

Description

This dataset contains the data supporting the manuscript "Antimicrobial activity of hydroethanolic extracts of four Nigerian spices, alone and in blends, and their use as a wash for cucumber and tomato" (R. N. Attaugwu and M. U. Anyaeche, Prince Abubakar Audu University, Anyigba, Nigeria). Plant material and extraction: Dried Uziza (Piper guineense, A), Uda (Xylopia aethiopica, B), Ehuru (Monodora myristica, C) and Aidan fruit (Tetrapleura tetraptera, D) were bought in Anyigba, Kogi State, cleaned, air-dried and ground. Fifty grams of each powder was macerated in 500 mL of 70 % (v/v) ethanol for 72 h at room temperature, filtered (Whatman No. 1), concentrated by rotary evaporation at 40 °C and reconstituted in sterile distilled water to a 100 % (w/v, 1 g/mL) stock; 50 % and 25 % solutions were made in sterile distilled water. Ten equal-volume blends were tested (AB, AC, AD, BC, BD, CD, ABC, ACD, BCD, ABCD); CD was not tested against E. coli. Test organisms: Escherichia coli (from lettuce and cucumber, eosin methylene blue agar), Staphylococcus aureus (from meat pie and vegetable salad, mannitol salt agar) and Aspergillus niger (from groundnuts and dried pepper, Sabouraud dextrose agar), identified by morphology, Gram reaction and biochemical tests (bacteria) and by colony and lactophenol cotton blue microscopy (fungus). Bacteria were standardized to 0.5 McFarland; A. niger conidia were suspended in 0.1 % (v/v) Tween 80, filtered through glass wool, counted with a haemocytometer and adjusted to 1 × 106 spores/mL. Agar well diffusion (Tables 1, 2, 4, 5, 6 and 7): Mueller-Hinton agar (bacteria) and Sabouraud dextrose agar (A. niger); 6 mm wells, 100 µL per well; tetracycline 30 µg and nystatin 100 IU discs as positive controls; sterile distilled water as negative control. Bacteria 37 °C for 24 h; A. niger 28 ± 2 °C for 72 h after 30 min pre-diffusion. Zones (mm) include the well. Triplicate readings, except the S. aureus blend plates (single readings). MIC, MBC and MFC (Table 3): tube broth dilution over concentrations decreasing in steps of 10 mg/mL; MBC or MFC by sub-culture of clear tubes onto the isolation media; single determinations, in mg/mL. Produce trial (Table 8): two lots each of cucumber and tomato (bought 22 May 2025); 500 g per treatment immersed for 3 min in 2 L of extract A (50 %), blend ABCD (50 %), calcium hypochlorite (100 ppm free available chlorine) or potable water, then rinsed with sterile water (no chemical neutralizer). Total viable bacterial count on nutrient agar (37 °C, 24 h), three counts per lot and treatment, with percentage and log10 reduction against the untreated portion of each lot. Statistics: individual replicate readings were not retained, so one-way and two-way ANOVA and Tukey's HSD test (p < 0.05) were computed from the means, SDs and n = 3 of each treatment (exact for a balanced design), in Python 3 (NumPy and SciPy).

Steps to reproduce

Dried seeds of Piper guineense, Xylopia aethiopica, Monodora myristica and Tetrapleura tetraptera were ground. Fifty grams of each powder was macerated in 500 mL of 70 % (v/v) ethanol for 72 h, filtered through Whatman No. 1 paper, concentrated by rotary evaporation at 40 °C and reconstituted in sterile distilled water to 1 g/mL (100 %); 50 % and 25 % solutions were made in sterile distilled water. Blends were prepared by mixing the stock extracts in equal volumes. Test organisms were food isolates of Escherichia coli, Staphylococcus aureus and Aspergillus niger. Bacterial suspensions were standardized to 0.5 McFarland, and A. niger spores were suspended in 0.1 % Tween 80 and adjusted to 1 × 10⁶ spores/mL. For agar well diffusion, plates of Mueller-Hinton agar (bacteria) and Sabouraud dextrose agar (A. niger) were seeded, and 6 mm wells were filled with 100 µL of sample. Tetracycline (30 µg) and nystatin (100 IU) discs were the positive controls and sterile distilled water the negative control. Bacteria were incubated at 37 °C for 24 h and A. niger at 28 ± 2 °C for 72 h, and zones were measured in millimetres including the well. MIC was determined by tube dilution over concentrations decreasing in steps of 10 mg/mL, and MBC or MFC by sub-culture onto the isolation media. For the produce trial, 500 g of cucumber or tomato per treatment was immersed for 3 min in 2 L of extract A (50 %), blend ABCD (50 %), calcium hypochlorite (100 ppm free available chlorine) or potable water, then rinsed with sterile water. Ten grams of each sample was homogenized, serially diluted and plated on nutrient agar at 37 °C for 24 h.

Institutions

• Kogi State University

  Kogi State, Dekina

Categories

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