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Abstract：
The food industry is still searching for novel solutions to effectively ensure the microbiological safety of food, especially fresh and minimally processed food products. Nowadays, the use of bacteriophages as potential biological control agents in microbiological food safety and preservation is a promising strategy. The aim of the study was the isolation and comprehensive characterization of novel bacteriophages with lytic activity against saprophytic bacterial microflora of minimally processed plant-based food products, such as mixed leaf salads. From 43 phages isolated from municipal sewage, four phages, namely Enterobacter phage KKP 3263, Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 have lytic activity against Enterobacter ludwigii KKP 3083, Citrobacter freundii KKP 3655, Enterobacter cloacae KKP 3082, and Serratia fonticola KKP 3084 bacterial strains, respectively. Transmission electron microscopy (TEM) and whole-genome sequencing (WGS) identified Enterobacter phage KKP 3263 as an Autographiviridae, and Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 as members of the Myoviridae family. Genome sequencing revealed that these phages have linear double-stranded DNA (dsDNA) with sizes of 39,418 bp (KKP 3263), 61,608 bp (KKP 3664), 84,075 bp (KKP 3262), and 148,182 bp (KKP 3264). No antibiotic resistance genes, virulence factors, integrase, recombinase, or repressors, which are the main markers of lysogenic viruses, were annotated in phage genomes. Serratia phage KKP 3264 showed the greatest growth inhibition of Serratia fonticola KKP 3084 strain. The use of MOI 1.0 caused an almost 5-fold decrease in the value of the specific growth rate coefficient. The phages retained their lytic activity in a wide range of temperatures (from -20 °C to 50 °C) and active acidity values (pH from 4 to 11). All phages retained at least 70% of lytic activity at 60 °C. At 80 °C, no lytic activity against tested bacterial strains was observed. Serratia phage KKP 3264 was the most resistant to chemical factors, by maintaining high lytic activity across a broader range of pH from 3 to 11. The results indicated that these phages could be a potential biological control agent against saprophytic bacterial microflora of minimally processed plant-based food products.
摘要：
食品工业仍在寻找新的解决方案，以有效确保食品的微生物安全，特别是新鲜和最低限度加工的食品。如今,在微生物食品安全和保存中使用噬菌体作为潜在的生物防治剂是一个有前途的策略。该研究的目的是分离和全面表征新型噬菌体，该噬菌体具有针对最低限度加工的植物食品的腐生细菌菌群的裂解活性，如混合叶沙拉。从城市污水中分离出的43只噬菌体，四个噬菌体,即肠杆菌噬菌体KKP3263，柠檬酸杆菌噬菌体KKP3664，肠杆菌噬菌体KKP3262和沙雷氏菌噬菌体KKP3264对路德维吉肠杆菌KKP3083，弗氏柠檬酸杆菌KKP3655，阴沟肠杆菌KKP3082和沙雷氏菌KKP3084菌株具有裂解活性，分别。透射电子显微镜（TEM）和全基因组测序（WGS）将肠杆菌噬菌体KKP3263鉴定为自拟病毒科，和柠檬酸杆菌噬菌体KKP3664，肠杆菌噬菌体KKP3262和沙雷氏菌噬菌体KKP3264作为Myoviridae家族的成员。基因组测序显示，这些噬菌体具有线性双链DNA（dsDNA），大小为39,418bp（KKP3263），61,608bp（KKP3664），84,075bp（KKP3262），和148,182bp（KKP3264）。没有抗生素抗性基因，毒力因子，整合酶,重组酶，或阻遏物，它们是溶源病毒的主要标记，在噬菌体基因组中进行了注释。沙雷氏菌噬菌体KKP3264对鸡沙雷氏菌KKP3084菌株的生长抑制最大。使用MOI1.0导致特定增长率系数的值降低了近5倍。噬菌体在宽范围的温度(-20°C至50°C)和活性酸度值(pH从4至11)中保持其裂解活性。所有噬菌体在60°C下保留至少70%的裂解活性在80°C时,未观察到针对测试细菌菌株的裂解活性。沙雷氏菌噬菌体KKP3264对化学因子的抗性最强，通过在3至11的更宽pH范围内保持高裂解活性。结果表明，这些噬菌体可能是针对最低限度加工的植物性食品的腐生细菌菌群的潜在生物防治剂。
