Microbiological Quality of High-Value Vegetables Grown with Biodegradable Cellulose Hydrogel under Varying Irrigation Regimes

Vegetables are increasingly associated with outbreaks of foodborne pathogens, raising concerns over
the safety of fresh produce and causing substantial economic losses worldwide. Alternative cultivation
systems such as soilless and hydrogel-based agriculture are being explored to improve produce safety
and sustainability. This study assessed the microbiological quality of high-value vegetables (tomato,
chili, cucumber, lettuce, and kale; n = 120 samples) cultivated with biodegradable cellulose hydrogel
of varying formulations. A total of 24 hydrogel–soil–irrigation combinations were evaluated,
incorporating hydrogel concentrations (0–100%) and irrigation intervals (1–6 days). Aerobic
mesophilic bacterial counts ranged from 0.33 ± 0.05 to 4.67 ± 0.12 log CFU g⁻¹, while coliform counts
were highest in lettuce (3.85 ± 0.09 log CFU g⁻¹) and lowest in tomato (1.12 ± 0.04 log CFU g⁻¹).
Neither Salmonella spp. nor Staphylococcus aureus were detected in any sample (n.d.). The 40%
hydrogel + 60% topsoil formulation with a 4-day irrigation interval yielded approximately 30–45%
lower total bacterial counts than the non-hydrogel control. These results suggest that integrating
biodegradable cellulose hydrogel into vegetable cultivation is associated with reduced microbial loads
and more efficient water use, supporting its potential role in sustainable high-value vegetable production.