Action of plasma-activated lactic acid on the inactivation of inoculated Salmonella Enteritidis and quality of beef

Authors: QIAN, JING - Nanjing Agricultural University; Zhuang, Hong; NASIRU, MUSTAPHA M. - Nanjing Agricultural University; MUHAMMAD, UMAIR - Nanjing Agricultural University; ZHANG, JIANHAO - Nanjing Agricultural University; YAN, WENJING - Nanjing Agricultural University

Submitted to: Innovative Food Science and Emerging Technologies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2019
Publication Date: 7/20/2019
Citation: Qian, J., Zhuang, H., Nasiru, M., Muhammad, U., Zhang, J., Yan, W. 2019. Action of plasma-activated lactic acid on the inactivation of inoculated Salmonella Enteritidis and quality of beef. Innovative Food Science and Emerging Technologies. https://doi.org/10.1016/j.ifset.2019.102196.
DOI: https://doi.org/10.1016/j.ifset.2019.102196

Interpretive Summary: Salmonella is one of the common foodborne pathogens. According to the Centers for Disease Control and Prevention, it is estimated that Salmonella causes 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths every year in the U.S. Beef is regarded as a commonly reported Salmonella carrier. Thus, Salmonella not only affects human health, but also results in a great economic loss in the meat industry due to product recalls and human illness resulting from consumption of contaminated beef and beef products. Lactic acid is a common additive in food and has been commonly applied as an antibacterial agent in meat processing. However, a high concentration of lactic acid ( > 1 %) could affect the quality of treated meat. The objective of the present study was to evaluate the antimicrobial effectiveness of plasma-activated lactic acid (PALA) solution against Salmonella on beef. The effect of PALA on the color, pH, lipid oxidation, and odor of treated beef was also investigated. Our results show that the immersion of beef inoculated with Salmonella bacteria in PALA (= 0.20%) for 20 sec resulted in reduction in bacterial counts by 1.24 to 3.52 log CFU/g with no negative effect on beef quality parameters, color, pH, lipid oxidation, and odor. This study demonstrates that PALA could be an effective alternative for treating beef to improve its safety.

Technical Abstract: This study aimed to investigate the effects of plasma-activated lactic acid (PALA) on Salmonella Enteritidis and beef quality. To improve the antibacterial efficiency of plasma-activated water (PAW), plasma-activated lactic acid (PALA) was prepared by treating lactic acid (0.05--0.20%) with a plasma jet for 40 to 100 s with subsequent application to the surfaces of beef slices (50 x 50 mm, approximately 10 g). Slices were analyzed for changes in surface color, pH, lipid oxidation and odor. ln addition, secondary structure (ß-sheet and random coil) of the beef protein was determined using Fourier transform infrared spectrometer. We showed that the antibacterial activity of PALA was closely related to the reaction of NO2- with H2O2 as well as the decomposition of NO2- under acidic conditions. UV-treated fresh beef slices were spot-inoculated with Salmonella Enteritidis (5.67 log CFU/g) and then immersed in PALA solutions for 20 s; leading to a reduction ranging from 1.24 to 3.52 log CFU/ g. Data indicated that there was no negative effect of PALA on beef quality parameters. This study not only provided a theoretical basis for developing a novel decontaminant but also enabled PALA to find a way for practical application.