百里香精油应用于肉类干燥过程中微生物负荷的影响
Summary
微生物如大肠杆菌污染肉类产品会引起食源性疾病. 精油在肉类干燥过程中的应用尚未深入研究。在此, 我们提出了一种新的方法, 将百里香精油应用于肉类干燥过程中, 以减少干肉中的微生物负荷。
Abstract
肉类是一种高蛋白的膳食, 用于配制干, 一种流行的食品零食, 在那里保存和安全是重要的。为了保证食品安全和延长肉类和肉类产品的保质期, 使用合成或天然防腐剂来控制和消除食源性细菌。越来越多的人对天然食品添加剂在肉类中的应用增加了兴趣。微生物, 如大肠杆菌, 污染肉类和肉类产品, 造成食源性疾病. 因此, 有必要改进肉类的保护过程。然而, 在肉类干燥时使用精油还没有深入研究。在这方面, 有机会增加干肉的价值, 并通过在干燥过程中应用精油降低食源性疾病的风险。在本议定书中, 我们提出了一种新的方法来应用百里香精油 (特奥) 在肉类干燥, 特别是在蒸气形式直接在干燥室。为了评估, 我们使用最小的抑制浓度 (MIC) 来检测样本中有害细菌的数量与原样品相比。初步结果表明, 该方法是一种可行的、可替代的合成防腐剂, 大大减少了干肉中的微生物负荷。
Introduction
干燥作为传统的保存食物的方法已经被使用了从远古时代。如今, 对干燥的兴趣越来越浓厚, 作为一种有效的食品保鲜方法1,2,3。它是用来制造各种特殊加工的肉类。其中最知名的是干。
干法是肉类保鲜的最古老的方法之一, 其基础是固化和干燥, 以降低水分活动, 从而延长其保质期4。如今, 干腌肉仍然很受欢迎, 食品的安全性、风味和质地是必不可少的。干制剂可用于几乎任何类型的肉类, 包括牛肉, 猪肉, 家禽, 或游戏5, 它需要切肉在瘦肉条和干燥。通常, 浸泡在固化溶液中的肉或吸烟与干燥一起使用, 以使干它的特色风味6。
尽管干燥的巨大兴趣, 以真正保存食物, 食源性暴发的风险由大肠杆菌从干燥肉是关键的, 需要控制。有一些研究报告食源性胃肠炎暴发, 特别是与大肠杆菌O157:H7, 归因于不充分的热处理在家庭干燥。即使在商业准备的生涩的7、8、9中也发生类似情况。莱文et al。10建议, 食源性微生物可以在干燥条件 (约60°c) 的情况下生存。大肠杆菌O157:H7 二十世纪九十年代中旬的食源性疾病暴发归因于地面干肉制品6,11。有趣的是, 在以前的所有病例中, 主要的风险是由被确认为可行但非可培养 (VBNC) 的细菌病原体引起的。在诸如温度变化或饥饿等各种压力下,大肠杆菌单元可以进入一个称为 VBNC 状态1213的特定状态。VBNC 细胞可以通过暴露在适当的条件下恢复到可培养细胞, 然后由于食源性污染而对人类健康构成威胁 14, 15.这意味着, 如果肉类是在干燥后立即消耗的产品, 它是安全的。但是, 如果储存不足, 如湿度增加, 病原体和微生物生长的复发风险很高。
除了干燥和腌料的方法, 消费者有很高的需求, 使用天然产品作为替代添加剂, 以改善食品质量16,17。对肉类天然食品添加剂的应用特别感兴趣, 而不是传统的合成防腐剂18,19,20,21。尽管在干燥肉类时使用精油缺乏足够的实验证据, 但该领域早期的研究已经显示出积极的结果22,23。
自中世纪以来, 人们已经认识到必需的油脂化合物 (EOCs) 的抗菌剂, 杀虫, 和寄生虫特征24,25,26。今天, EOCs 是最重要的一组生物活性天然化合物的一部分。在不同的 EOCs 中, 麝香是其中一个最知名的。它由85% 以上的特奥23组成。这种苯酚能防止微生物和化学物质在食物中变质。此外, 它的抗菌性能可能会改善与其他天然防腐剂2,27,28,29,30。现在, 百里香 (胸腺), 一种属于唇形家族的药草, 已被公认为调味剂, 也是一种非常有效的肉类防腐剂 31.由加西亚-Díez et进行的一项研究。30在肉类产品上发现, 与其他精油相比, 特奥对食源性致病菌的抑制作用更大。因此, 在干燥过程中施用精油, 有机会增加干肉的价值, 减少食源性疾病的风险。
在本协议中, 我们提出了一种新的方法来应用特奥在肉类干燥, 特别是使用它在蒸气形式直接在干燥室。为了评估, 我们使用麦克风来确定治疗样本中的致病菌与原生细菌的缺失。初步结果表明, 该方法是一种高效的合成防腐剂替代品, 大大减少了干肉中的微生物负荷。
Protocol
1. 肉类制剂 从当地的屠杀中获得一小块牛肉 (从股二头肌中的新鲜牛肉), 转移到实验室。注: 建议在常温下 (20-25 °c) 运输牛肉的腰部, 在密封袋内不超过20分钟。 为了对牛肉肌肉的外层进行消毒, 在层流安全柜中, 用500毫升的挤压瓶喷洒 70% (v/v) 乙醇, 以洗涤肌肉。应用0.025 克乙醇每1厘米的肌肉表面2 。 用小刀除去肉灌装的外表面, 以避免在肌肉内部残留乙醇…
Representative Results
我们首先开发了这种方法, 通过使用牛至精油 (OEO), 以提高食品安全和提高干肉的价值。一般而言, 上述实验表明, 在干燥过程中,大肠杆菌进入 VBNC 状态作为一种生存策略。这是由事实证明, 在干燥完成后没有可培养细菌 22.因此, 6 小时的预浓缩过程是必要的, 以允许计数的应变。在较短的时期内, 生长细胞的数量仍然非常低。结果是在预富集过程后, …
Discussion
先前的研究表明, 导致食源性疾病的微生物在干燥过程中生存了10。因此, 必须在干燥前应用防腐剂, 以保证食品安全。在这项研究中, 我们专注于使用特奥。其原因有两个方面: 第一, 消费者对使用天然产品作为替代添加剂以提高食品质量的需求很高16;其次, 前一项研究表明, 在肉类干燥过程中使用 OEO 的结果为22。因此, 在肉类干燥过程中应用 OEO…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项工作得到了热带 AgriSciences 学院内部赠款机构的支持 (项目编号: 20175013) 和 CIGA 20182023 两项赠款, 来自捷克生命科学大学。
Materials
| Meat cutter | Kalorik | KP 3530 | from Miami Gardens, FL, USA |
| Laminar safety cabinet | Faster s.r.l | from Italy | |
| Squeeze bottle of 500 mL | Merci | 632 524 325 025 | from CZ |
| Standard laboratory drier UFE 400 | Memmert | DE 66812464 | from Germany |
| Incubator | BT 120 | N/A | from CZ |
| Refrigerator and Freezer | Bosch | KGN34VW20G | from DE |
| Densitometer | Biosan | 220 000 050 122 | Latvia; supplier Merci, CZ |
| Escherichia coli ATCC 25922 | Oxoid | CL7050 | from CZ |
| Vortex | Chromservis | 22008013 | from CZ |
| Sterilized plastic tubes 15 mL | Gama | 331 000 020 115 | from CZ, supplier Merci |
| 20 mL injection vial | Healthy vial | hvft169 | from China |
| 20 mm sterile butyl rubber stopper | Merci | 22008013 | from CZ |
| 20 mm aluminum cap | Healthy vial | N/A | from China |
| Thyme essential oil | Sigma Aldrich | W306509 | from St Louis, MO, USA |
| Mueller Hinton Broth | Oxoid | CM0337 | from CZ |
| NaCl | Penta | 16610-31000 | from CZ |
| Peptone | Oxoid | LP0034 | from CZ |
| Phosphate-buffered saline | Sigma Aldrich | P4417 | from CZ |
| Polysorbate 80 (Tween 80) | Roth | T 13502 | from DE, supplier P-lab |
| Shaker SHO-1D | Verkon | DH.WSR04020 | from CZ, 10 – 300 rpm. 350 x 350 mm with a platform for flasks |
| Ethanol 70% | Bioferm | N/A | from CZ |
| MacConkey Agar | Oxoid | CM007 | from CZ |
| Plate Count Agar | Oxoid | CM0325 | from CZ |
| Filter paper | Merci | 480 622 080 040 | from CZ |
| Erlenmeyer flasks 250 mL | Simax | 610 002 122 636 | from CZ; supplier Merci CZ |
| Multichannel pipette | Socorex | S852820 | from Switzerland; supplier P lab, CZ |
| Microtiter plate | Gamma | V400916 | CZ |
| Microlitre pipette 100-1000 μL | Eppendorf | 333 120 000 062 | from Germany; supplier Merci, CZ |
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Cite This Article
Hernández, H., Fraňková, A., Klouček, P., Banout, J. The Effect of the Application of Thyme Essential Oil on Microbial Load During Meat Drying. J. Vis. Exp. (133), e57054, doi:10.3791/57054 (2018).