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Microbial growth inhibition and decomposition of milk mineral and sodium tripolyphosphate added to media or fresh ground beef.

机译：添加到培养基或新鲜碎牛肉中的牛奶矿物质和三聚磷酸钠的微生物生长抑制和分解。

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摘要

Milk mineral (MM) is a type II antioxidant (metal chelator) that can bind iron and prevent iron catalysis of lipid oxidation. Thus, MM might have microbial growth inhibition effects on iron-dependent bacteria. Objective 1 was to evaluate effects of MM on growth of non-pathogenic iron-dependent bacterial strains (Listeria innocua, Eschericia coli, Pseudomonas fluorescens). MM (1.5% w/v) did not significantly inhibit growth of Listeria and E. coli. However, growth of Pseudomonas fluorescens was consistently and significantly reduced by ∼1 log colony forming units per ml (CFU/ml) with all levels of MM (0.5, 0.75, 1.5% w/v). All levels of MM also had no growth inhibition effects against the mixed microflora of fresh ground beef during storage for up to 10 days at 2°C. In conclusion, MM had little or no effect to inhibit microbial growth. The strong affinity of MM to ionic iron inhibits lipid oxidation, but does not inhibit bacterial growth supported by other forms of iron (heme or amino acid + iron complexes).;Several studies report that MM has greater antioxidant effect than sodium tripolyphosphate (STP) in ground meats, especially at longer storage time. Objective 2 was to compare stability of MM and STP in ground beef patties by monitoring the decomposition to soluble orthophosphates (Pi). Patties (control) and patties with 0.75% MM or 0.5% STP were stored at 2 or 22°C for 0, 1, or 2 days. CFU/g and Pi were measured. As expected, CFU/g at 22°C was much higher than treatment at 2°C. Pi levels at 2°C were lower (P 0.05) than at 22°C. At day 0, for both temperatures, patties formulated with MM had the highest Pi levels. However, after 2 days storage, samples with added STP had the highest level of Pi, followed by MM and control. Thus, decomposition as measured by release of Pi was significantly higher for STP than for MM added to beef patties. There was a significant positive correlation (0.77) between CFU/g and Pi during storage of beef patties for 2 days at 22°C. In conclusion, increased Pi during storage of beef patties was at least partially due to bacterial phosphatases. A third experiment was conducted to examine the stability of 0.75% MM or 0.5% STP added to growing cultures of Pseudomonas fluorescens at 2°C or 22°C for 0, 1, and 2 days. Neither MM nor STP was stable in autoclaved media (Pi increased significantly). The factors responsible for decomposition of MM or STP in autoclaved media remain to be determined.
机译：牛奶矿物质（MM）是II型抗氧化剂（金属螯合剂），可以结合铁并防止铁催化脂质氧化。因此，MM对铁依赖性细菌可能具有微生物生长抑制作用。目的1是评估MM对非致病性铁依赖性细菌菌株（无毒李斯特菌，大肠埃希氏菌，荧光假单胞菌）生长的影响。 MM（1.5％w / v）没有明显抑制李斯特菌和大肠杆菌的生长。但是，在所有水平的MM（0.5、0.75、1.5％w / v）下，荧光假单胞菌的生长均持续且显着降低了约1个对数菌落形成单位/ ml（CFU / ml）。在2°C储存长达10天的过程中，所有水平的MM对新鲜碎牛肉的混合菌群也没有生长抑制作用。总之，MM对微生物生长的抑制作用很小或没有。 MM对离子铁的强亲和力抑制脂质氧化，但不抑制其他形式的铁（血红素或氨基酸+铁络合物）支持的细菌生长。；多项研究报告，MM具有比三聚磷酸钠（STP）更大的抗氧化作用在碎肉中，尤其是在较长的存储时间中。目标2是通过监测对可溶性正磷酸盐（Pi）的分解来比较MM和STP在碎牛肉肉饼中的稳定性。将肉饼（对照）和具有0.75％MM或0.5％STP的肉饼在2或22°C下保存0、1或2天。测量了CFU / g和Pi。不出所料，在22°C下的CFU / g远高于2°C下的处理。 2°C时的Pi含量低于（22°C）（P <0.05）。在第0天，两种温度下，用MM配制的肉饼的Pi含量最高。但是，储存2天后，添加了STP的样品的Pi含量最高，其次是MM和对照。因此，对于STP而言，通过Pi释放所测得的分解显着高于添加至牛肉饼中的MM。在22°C下牛肉储存2天期间，CFU / g与Pi之间存在显着正相关（0.77）。总而言之，牛肉馅饼存储过程中的磷增加至少部分是由于细菌的磷酸酶引起的。进行第三项实验，以检查添加到2℃或22℃下0、1和2天的荧光假单胞菌生长培养物中的0.75％MM或0.5％STP的稳定性。 MM和STP在高压灭菌的培养基中均不稳定（Pi显着增加）。造成高压灭菌介质中MM或STP分解的因素还有待确定。

著录项

  • 作者

    Tansawat, Rossarin.;

  • 作者单位

    Utah State University.;

  • 授予单位 Utah State University.;
  • 学科 Agriculture Food Science and Technology.;Biology Microbiology.
  • 学位 M.S.
  • 年度 2009
  • 页码 75 p.
  • 总页数 75
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农产品收获、加工及贮藏;微生物学;
  • 关键词

  • 入库时间 2022-08-17 11:37:37

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