102: Atmospheric Cold Plasma as a Non-Thermal Alternative to Inactivate Escherichia Coliin Black Soldier Fly Larvae (Hermetia Ilucens) Flour

Introduction

The rising global demand for sustainable protein alternatives has brought BSFL flour into focus due to its nutritional value and low environmental impact. However, microbial pathogens present a significant food safety risk, and traditional thermal processes often compromise product quality. Atmospheric Cold Plasma (ACP), a non-thermal process, has shown microbial safety potential but requires further validation for BSFL flour treatment.

Methods

BSFL from a local company was harvested once they exceeded 150 mg in weight. The substrate was dried to a moisture content of 6%, ground coarsely, freeze dried for 13h, and defatted. 5g of BSFL flour were inoculated with Escherichia coli MG1665, placed in open Petri dishes and sealed in a plastic bag filled with 65% oxygen, 30% carbon dioxide, and 5% nitrogen. Samples were subjected to ACP treatment of 70 Kv and 80 Kv for 5 to 8 minutes. After treatment, samples were incubated overnight to allow gases to permeate the bags. Microbial colonies were enumerated by hand. Untreated samples served as controls. Hausner Ratio (HR), Carr’s Index (CI), moisture content, water activity, pH, and color values were recorded to assess the effect of ACP on flour quality and flowability.

Results

ACP treatment reduced (p < 0.05) microbial loads from an initial count of 5×105 CFU/g. At 70 kV, a 3-log reduction was achieved within 5 minutes, with a maximum reduction of 3.33 log units at 8 minutes. At 80 kV, a 3.13-log reduction was achieved at 5 minutes and 3.3 log reductions were maintained between 6 and 8 minutes. ACP did not affect (p < 0.05) the pH, water activity, and moisture content of the BSFL ground materials. Average moisture content was 9.54 +/- 0.05 % wet basis for both sample groups. ACP-treated samples were darker (p<0.05) in color. In contrast, ACP treatment affected (p > 0.05) the handling properties of the flours with HR values between 1.30 compared to 1.00 for the control.

Significance

This study highlights the potential of ACP as an effective, non-thermal method for inactivating Escherichia coli in BSFL flour, offering a promising solution to produce safe, high-quality BSFL flour for use in human foods.

Authors: Pearl Pinto, Rosana G. Moreira, M.E. Castell-Perez