Investigation into the antibacterial and freshness preservation efficacy of dry porous bags of biomass ash from agricultural residues

Biomass ash from agricultural residues, which is typically discarded and causing waste and pollution, was evaluated in tea-bag form as a natural food preservative in this study, addressing research gaps on its effects and safety. In vitro tests on six biomass ash extracts demonstrated significant antibacterial activity. Specifically, the golden leaf fine branch camellia extract exhibited the highest efficacy against Staphylococcus aureus and Alternaria brassicicola, with an inhibition zone of 21 mm and an antibacterial efficiency of 70.2%. Fruit storage tests confirmed its preservative ability. Golden leaf fine branch camellia twig and leaves ash exhibited the most effective weight loss reduction for potatoes, corn stalks ash was found to be optimal for green peppers, rice straw ash offered the most effective preservation for sugar oranges, and soybean straw ash yielded favorable outcomes for mangoes. Safety evaluations revealed no genotoxicity, with lead content below the 0.2 mg/kg safety threshold and the micronucleus tests within safe limits. Elemental analysis detected high potassium content (103.127 g/kg), while SEM and FTIR revealed a porous structure and functional groups that may contribute to its antibacterial and preservative properties. In conclusion, biomass ash has strong antimicrobial and preservative properties, is non-genotoxic, and shows great potential as a natural food preservative, providing a new avenue for biomass ash resource utilization.