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• Contamination and Molecular Characterization of Salmonella spp. Isolated from Pig Carcasses and Pork Collected from Slaughterhouses and Retail Markets in Thai Binh Province

  Nguyen Thi Lan, Nguyen Thi Thu Hang, Tran Hiep, Tran Thi Khanh Hoa, Pham Thuy Linh, Nguyen Thi Huong Quynh, Nguyen Van Thang, Cam Thi Thu Ha, Hoang Minh Son, Hoang Minh Duc

  Received: May 26, 2026 / Accepted: Jun 29, 2026 / Published: Jun 30, 2026

   Abstract PDF

  Pork is considered one of the major vehicles for Salmonella transmission to humans. This study aimed to determine the prevalence, serovar distribution, and virulence gene profiles of Salmonella isolates recovered from pig carcasses and pork in Thai Binh province. A total of 192 samples, comprising carcass swabs and pork samples, were collected from slaughterhouses and wet markets. Salmonella was detected in 22.92% (44/192) of the samples, with prevalence rates of 25.00% (24/96) in slaughterhouses and 20.83% (20/96) in wet markets. Among the 44 Salmonella isolates, only S. Typhimurium (31.82%, 14/44) and S. Virchow (4.55%, 2/44) were identified using the PCR-based serotyping assay targeting five selected serovars, whereas 63.63% (28/44) of the isolates remained untyped. The virulence genes invA, msgA, tolC, lpfC, pagC, and spaN were detected at relatively high frequencies of 100%, 90.91%, 77.27%, 72.73%, 70.45%, and 70.45%, respectively. In contrast, the spvC gene was found in only 4.5% of the isolates, whereas none carried the cdtB gene. The results of ESBL test showed that 27.27% (12/44) of the isolates were ESBL producers carrying blaCTX-M-1, blaCTX-M-9, and blaTEM genes. The detection of ESBL-producing Salmonella in carcasses and pork highlights a potential public health risk and underscores the need for enhanced food safety surveillance and intervention measures to reduce Salmonella contamination.

• Isolation and Characterization of Saccharomyces cerevisiae with Antagonistic Activity against Salmonella pullorum

  Nguyen Thi Lan, Tran Hiep, Hoang Minh Son, Nguyen Van Thang, Nguyen Thi Thu Hang, Nguyen Thi Huyen, Truong Long Van, Hoang Minh Duc

  Received: Nov 01, 2025 / Accepted: Dec 30, 2025 / Published: Dec 31, 2025

   Abstract PDF

  Saccharomyces cerevisiae is considered to be an alternative to antibiotics in reducing the growth of pathogenic bacteria and enhancing the mucosal immune system. In countries with developed livestock industries, antibiotic resistance of Salmonella pullorum is still causing difficulties in controlling Pullorum disease. This study aimed to isolate and select S. cerevisiae strains with antagonistic activity against S. pullorum for potential application in probiotics production. A total of eight S. cerevisiae strains were isolated from 50 ripe mango samples. All the isolated strains exhibited inhibitory effects against S. pullorum. Among them, strains SC1, SC6, and SC8 showed strong antagonism, with inhibition zone diameters of 16 ± 0.87mm, 16 ± 0.50mm, and 17 ± 1.80mm, respectively. These isolates exhibited high stability under various conditions. These findings suggest that S. cerevisiae strains SC1, SC6, and SC8 are potential candidates for producing a probiotic to control poultry diseases.

• Effect of Fish Protein Hydrolysate Concentrations on the Growth and Quality of Hydroponic Lettuce (Lactuca sativa L.)

  Do Thi Huong, Phan Thi Thuy

  Received: Oct 27, 2025 / Accepted: Feb 10, 2026 / Published: Jun 30, 2026

   Abstract PDF

  The study investigated the effects of fish protein hydrolysate (FPH), derived from fish processing by-products, on the growth, yield, and quality of lettuce (Lactuca sativa L.) grown in a static hydroponic system. Four nutrient treatments were evaluated: a control using a commercial inorganic Snap solution (T1) and three FPH-based solutions at concentrations of 300ppm (T2), 600ppm (T3), and 900ppm (T4). Results showed that the 600ppm FPH treatment (T3) significantly enhanced plant growth and physiological performance compared with the control. Lettuce under T3 achieved the greatest root length (21.4cm), canopy diameter (27.6cm), SPAD value (38.5), and fresh yield (438.2 g plant-1), representing a 22-30% increase over T1. Quality attributes also improved under moderate FPH application. Vitamin C content increased to 10.5 mg 100 g-1 in T3 compared with 7.5 mg 100 g-1 in the control, while nitrate concentration decreased markedly from 398.5 to 242.1 mg 100 g-1. Soluble solids content rose from 3.7 to 4.2°Brix, indicating improved sweetness and flavor. No Escherichia coli or Salmonella spp. contamination was detected in any treatment, confirming product safety. Overall, the application of 600ppm FPH provided an optimal balance between yield, nutritional quality, and microbial safety. These findings demonstrate that fish protein hydrolysate offers a cost-effective and sustainable nutrient alternative for hydroponic lettuce production, promoting circular resource utilization and environmentally friendly agriculture.

• Optimizing Input Materials to Enhance Egg-Based Fertilizer Quality and Assessing Its Performance in Malabar Spinach (Basella alba) Cultivation

  Phan Thi Thuy, Nguyen Thi Ai Nghia, Le Thi Hong Van, Do Thi Huong

  Received: Aug 13, 2025 / Accepted: Jan 23, 2026 / Published: Jun 30, 2026

   Abstract PDF

  This study explored a sustainable approach to agricultural waste management by converting spoiled eggs into high-quality liquid fertilizers. Egg-based fertilizers (EFs) produced from different input compositions were characterized for their physicochemical properties, and the most suitable EF was further evaluated for its effects on the growth, physiological performance, and yield of Malabar spinach (Basella alba). Three treatments were prepared: EF1 (spoiled eggs without chicks), EF2 (spoiled eggs with chicks), and EF3 (a 1:1 mixture of both). EF1 contained the highest levels of total nitrogen (6.09 g L-1), total and available phosphorus (1.05 and 0.80 g L-1 P₂O₅, respectively), and total calcium (3.79 g L-1 CaO), with no detectable Escherichia coli or Salmonella. EF3 exhibited the highest potassium content (1.16 g L-1 total and 1.04 g L-1 available K₂O). In a field trial, EF1 was applied at 1.0%, 1.5%, and 2.0%, and compared with a commercial organic fish fertilizer and an unfertilized control. Applications of EF1 at 1.5% significantly enhanced shoot length, leaf dimensions, SPAD, leaf area index (LAI), and yield (6.3 and 11.9 t ha-1 at 21 and 37 days after planting, respectively). Yield showed strong positive correlations with leaf length (r = 0.96**), leaf width (r = 0.92**), SPAD (r = 0.84**), and LAI (r = 0.90**), supporting the observed treatment effects. Nitrate concentrations in all the treatments remained below 150 mg kg-1, within safe limits for leafy vegetables. Overall, EF1 at 1.5% represents a safe, effective, and sustainable fertilization option for Malabar spinach production.