Spore germination and lactic acid combined treatment: A new strategy for the shelf-life extension of instant wet noodles

Abstract

Bacillus amyloliquefaciens (BAM) was the primary spoilage bacteria in instant wet noodles (IWNs), so reducing BAM spores was crucial to extending shelf-life. This study proposed a strategy combining spore germination (SG) and lactic acid (LA) treatment for the shelf-life extension of IWNs. In liquid culture medium, L-histidine was an efficient germinant and increased the SG rate 1.05 times. The acid mortality of spores was increased to 83.57% at pH 3.0 while increasing the membrane permeability of the spores. In IWNs, compound germinants (1% L-histidine, 0.5% D-glucose, and 1% sodium chloride) increased the SG rate by 3.61 times. The strategy further increased spore heat death by 34.41%-41.68%, and led to a spore acid-heat death rate of 76.52%-94.03%. This strategy was significantly effective in IWNs processing, extending shelf-life by 3.00-5.50 times, and the pH to 5.5-6.6 for IWNs. Meanwhile, the comprehensive quality of IWNs improved. The strategy has potential applications in the development of IWNs with high quality and a long shelf-life.