Ongoing outbreaks of foodborne diseases remain a significant public health concern. Lytic phages provide promising attributes as biocontrol agents. This study characterized KFS-EC3, a polyvalent and lytic phage, which was isolated from slaughterhouse sewage and purified by cesium chloride density centrifugation. Host range and efficiency of plating analyses revealed that KFS-EC3 is polyvalent and can efficiently infect E. coli O157:H7, Salmonella spp., and Shigella sonnei. KFS-EC3 had a latent time of 20 min and burst size of ~71 phages/infected cell. KFS-EC3 was stable and infectious following storage at a pH range of 3 to 11 and a temperature range of −70 °C to 60 °C. KFS-EC3 could inhibit E. coli O157:H7 growth by 2 logs up to 52 h even at the lowest MOI of 0.001. Genomic analysis of KFS-EC3 revealed that it consisted of 167,440 bp and 273 ORFs identified as functional genes, without any genes associated with antibiotic resistance, virulence, allergenicity, and lysogenicity. This phage was finally classified into the Tequatrovirus genus of the Myoviridae family. In conclusion, KFS-EC3 could simultaneously infect E. coli O157:H7, S. sonnei, and Salmonella spp. with the lowest MOI values over long periods, suggesting its suitability for simultaneous pathogen control in foods.

We investigated the effects of steaming Fijian taro (Colocasia esculenta L. Schott) corms on their functional compound contents and antioxidant activities by comparison with those of un-steamed Fijian taro corms. Taro corms from Fiji were washed, peeled, cut, then either steamed or left un-steamed, and freeze-dried. Ten gram of each freeze-dried taro corm sample was extracted with water, methanol, and ethanol. The total phenolic content (TPC) and total flavonoid content (TFC) of the taro corms were determined using the Folin-Ciocalteu’s colorimetric and the aluminum chloride colorimetric methods, respectively. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity. The water-extracted steamed Fijian taro corm showed the greatest extraction yield of 11.58±1.20%, whereas the ethanol-extracted un-steamed Fijian taro corm exhibited the lowest extraction yield of 4.24±0.77%. The TPC (42.77±3.39 mg gallic acid equivalents/g dry weight) and TFC (12.68±4.85 mg catechin equivalents/g dry weight) of the methanol-extracted steamed Fijian taro corms were significantly larger than those of the other extracts (p<0.05). The steamed Fijian taro corms extracted with methanol significantly demonstrated greatest activities in DPPH radical scavenging activity (34.82±2.91%), FRAP (339.08±20.50 mM Trolox equivalents), and ABTS radical scavenging activity (56.34±3.54%) (p<0.05). This study provides the basis for developing a healthy snack food based on steamed Fijian taro.