Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2026Scopus SJRQ1/r/gumushane/16180
  An insight of oil protection theory: Survival, structural and metabolic adaptation of Salmonella enterica Enteritidis Phage Type 30 in three triglycerides

  Zhao, Huan; Sun, Rui; Cao, Shidi; Ozturk, Samet; Erdogdu, Ferruh; Liu, Xingyi; Liu, Shuxiang

  Oil protection theory posits that oil enhances microbial survival and heat resistance in low-moisture foods, yet the role of triglyceride composition remains poorly defined. This study investigates how Salmonella enterica Enteritidis PT 30 adapts during desiccation in peanut oil (mixed triglycerides, aw,25 degrees C = 0.30) and two representative components, namely, trilinolein and glyceryl trioleate. The lipid-specific structural and metabolic adaptations were analyzed through confocal microscopy and transcriptomics. S. Enteritidis exhibited the lowest persistence (3.43-log reduction over 180 days) and weakest heat resistance (2.5 h at 80 degrees C to achieve 3.5-log reduction) in peanut oil. The survival of S. Enteritidis in triglycerides could be correlated with its metabolic dormancy via suppression of ribosomal and oxidative phosphorylation pathways. Trilinolein enhanced S. Enteritidis' heat resistance (30 h at 80 degrees C for 3.5-log reduction) and moderate storage mortality (1.64-log reduction at 180 d), driven by stress hyperactivity. Glyceryl trioleate balanced heat tolerance (8 h) with optimal storage survival (1.19-log reduction), mediated by partial metabolic suppression. Peanut oil preserved S. Enteritidis transient motility in water-rich microenvironments, while pure triglycerides formed compact, dehydrated aggregates. Transcriptomics identified divergent strategies. Peanut oil induced dormancy at the expense of stress resilience, whereas homogeneous lipids imposed distinct constraints; that is, trilinolein amplified oxidative stress, and glyceryl trioleate intensified desiccation. These findings refine oil protection theory, demonstrating that lipid heterogeneity-not just low water activity-shapes microbial outcomes. The mixed components of peanut oil buffer stress but limit protective efficacy, while its purified constituents reveal how specific triglycerides modulate survival. This mechanistic understanding advances theoretical models of pathogen persistence in oily matrices and guides targeted strategies to mitigate risks in low-moisture oil-rich food systems.

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  AtıfWoS5·OpenAlex5

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• MakaleYalnız künye2026Scopus SJRQ1/r/gumushane/13435
  Thermal inactivation kinetics of Listeria monocytogenes in fat/water emulsions and fat tissue – effect of fat content

  Ozturk, Samet; Huang, Lihan; Hwang, Cheng-An; Sheen, Shiowshuh

  Significantly increased thermal resistance was found in Listeria monocytogenes inoculated to beef tallow. However, how the relative compositions of fat and water in emulsions affect bacterial survival during heating has not been evaluated. This study aimed to evaluate the effect of fat levels in solid fat/water (SF/W) emulsions on thermal resistance of L. monocytogenes. SF/W emulsions, containing 0, 25, 50, 60, and 75 % of tallow by weight, were prepared by mixing tallow with soybean lecithin and Tween 80 in 0.1 % peptone water using an ultrasonic processor. A 4-strain cocktail of L. monocytogenes was inoculated to the emulsions and subjected to isothermal heating between 55 and 65 °C. The survival curves were analyzed to estimate the kinetic parameters and evaluate thermal resistance. Linear survival was observed in emulsions with fat below 50 %. However, increased thermal resistance, evidenced by the increasing D and z values with the fat content, was observed. For example, the average D values in SF/W emulsions at 60 °C are 0.54, 1.04, and 2.53 min, respectively, with 0, 25, and 50 % fat. For SF/W emulsions with 60 and 75 % fat and in beef trim fat (BTF, 86.9 % fat), the survival curves became convexly nonlinear and could be described with the Weibull model. The exponents of the Weibull model range between 0.45 and 0.456, suggesting almost identical convexity of the survival curves. The convex survival curves indicate initial sensitivity to heat but the resistance increases with time at each temperature. The estimated time to a 5-log reduction becomes 11.9 and 26.4 min in 60 and 75 % SF/W emulsions, respectively, and 36.5 min in BTF at 60 °C. The study demonstrates the effect of fat levels on thermal resistance of L. monocytogenes in SF/W emulsions and BTF. The results of this study may help the food industry to properly kill L. monocytogenes in fat-containing meat products during thermal processing.

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  AtıfScopus2·WoS2·OpenAlex2

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• MakaleYalnız künye2023Scopus SJRQ1/r/gumushane/10342
  Effect of oil exposure stages on the heat resistance of Salmonella enterica serovar Enteritidis phage type 30 in peanut flour

  Liu, Shuxiang; Qiu, Yan; Ji, Kexin; Ozturk, Samet; Erdogdu, Ferruh; Qin, Wen; Yang, Ren; Wu, Qingping

  The oil in low-moisture foods (LMFs) shows protective effects on bacteria during thermal processing. However, the circumstances under which this protective effect strengthens remain unclear. This study aimed to understand which step of the oil exposure to bacterial cells (inoculation, isothermal inactivation, or recovery and enumer-ation step) in LMFs can enhance their heat resistance. Peanut flour (PF) and defatted PF (DPF) were selected as the oil-rich and oil-free LMF models. Salmonella enterica Enteritidis Phage Type 30 (S. Enteritidis) was inoculated into four designated PF groups representing different oil exposure stages. It was isothermally treated to obtain heat resistance parameters. At a constant moisture content (aw,25 degrees C = 0.32 +/- 0.02) and controlled aw,85 degrees C (0.32 +/- 0.02), S. Enteritidis exhibited significantly high (p < 0.05) D values in oil-rich sample groups. For instance, the heat resistance values of S. Enteritidis in the PF-DPF and DPF-PF groups were D80 degrees C of 138.22 +/- 7.45 min and 101.89 +/- 7.82 min; however, the D80 degrees C in the DPF-DPF group was 34.54 +/- 2.07 min. The oil addition after the thermal treatment also helped injured bacterial recovery in the enumeration. For instance, the D80 degrees C, D85 degrees C, and D90 degrees C values in the DFF-DPF oil groups were 36.86 +/- 2.30, 20.65 +/- 1.23, and 7.91 +/- 0.52 min, respectively, which were higher than those in the DPF-DPF group at 34.54 +/- 2.07, 17.87 +/- 0.78, and 7.10 +/- 0.52 min. We confirmed that the oil protected S. Enteritidis in PF in all three stages: desiccation process, heat treatment, and recovery of bacterial cells in plates.

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  AtıfWoS7·OpenAlex11

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