Rapid Detection of Pseudomonas in Spoiled Meats by Lateral Flow Immunochromatographic Assay

Abstract

Bacteria propagate during storage of raw meat, leading to spoilage. We developed a lateral flow immunochromatographic assay (LFIA) to rapidly assess the freshness/spoilage of raw meats. Amplicon analysis was performed on raw meats immediately after purchase and after being stored aerobically at 4°C for 10 days. The proportion of Pseudomonas increased 2.2–15.5 times as spoilage progressed. We prepared antibodies against putative Pseudomonas lundensis, Pseudomonas fragi, Pseudomonas bubulae/Pseudomonas kulmbachensi mixture, and putative P. lundensis, Pseudomonas edaphica, Pseudomonas canadensis mixture isolated from spoiled meats, and developed LFIAs (Plfbk-LFIA and Plec-LFIA, respectively). When the specificities were investigated using 70 strains representing 61 species from 32 genera, as selected from culture collection strains and meat isolates, Plfbk-LFIA showed strong positivity only for P. fragi, and Plec-LFIA showed strong positivity only for Pseudomonas sp. isolated from meats. We purchased 36 types of commercially available meat (minced chicken, minced pork, ground beef, and chopped pork) from different stores and found that both LFIAs could distinguish between fresh and spoiled meats, exhibiting accuracies of 91.7% and 94.4%, respectively. Plfbk-LFIA and Plec-LFIA tended to become positive when the target bacterium counts in the samples were around 6 and 7 log CFU/g, respectively. As the assay requires only 1 h, including pre-processing time, our novel method could be used to evaluate freshness at manufacturing and sales sites within the manufacturing date, and may contribute to reducing food loss by providing a rapid and convenient method for quality assessment.