Improving microbiological safety and quality of apple juice through lactic acid sanitization and <i>Lacticaseibacillus casei</i> biopreservation

This study investigates lactic acid as a sustainable alternative to sodium hypochlorite for apple sanitization in juice production, along with the addition of <i>Lacticaseibacillus casei</i> as a biopreservative. Lactic acid showed superior effectiveness in reducing microbial contamination, achieving reductions of 2.64 log CFU/mL for mesophilic aerobes, 2.41 log CFU/mL for molds and yeasts, and 2.41 log CFU/mL for Enterobacteriaceae. Notably, lactic acid-treated juice remained coliform-free for 11 days, with a significant delay in spoilage compared to sodium hypochlorite treatment. Combined with <i>L. casei</i>, the absence of coliforms was maintained over a 20-day refrigerated storage, suggesting a synergistic effect that enhances safety. Additionally, <i>L. casei</i> retained high viability in the lactic acid-treated juice, with counts of 6.48 log CFU/mL, confirming its potential as a biopreservative. The treatment lowered the juice pH, further inhibiting microbial growth and contributing to enhanced microbiological stability. This approach emphasizes the effectiveness of natural biopreservatives in fruit juice preservation, a focus often limited to animal-based products.