de Boer Paulo, Serra-Castelló Cristina, Berendsen Luciënne, Zwietering Marcel H, Nierop Groot Masja N
Wageningen Food & Biobased Research, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands.
Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands.
Int J Food Microbiol. 2025 Dec 2;443:111428. doi: 10.1016/j.ijfoodmicro.2025.111428. Epub 2025 Sep 4.
Listeria monocytogenes is a pathogen of concern in plant-based meat analogues (PBMAs). Testing L. monocytogenes growth behavior in real products at various conditions requires screening of a large set of conditions and timepoints which is time-consuming, hence costly. A representative model PBMA has been developed that allows to test L. monocytogenes growth in the presence of different growth inhibitory parameters. To minimise handling and disposable use, L. monocytogenes was enumerated using a miniaturized most probable number (mMPN) method, which showed good correlation to CFU counting. The model PBMA was further demonstrated for a range temperatures (7-15 °C), a (down to 0.940, adjusted by NaCl) and lactic acid and acetic acid concentrations (up to 2.5 mM and 6 mM undissociated acid, respectively). The growth of L. monocytogenes strain FBR017 was quantified, and the kinetic growth parameters were determined. Besides soy, other plant protein sources including pea, wheat and wheat/soy combinations were tested. All matrices readily supported growth of L. monocytogenes FBR017 and the μ determined on the fitted data showed similar rates for all protein types showing that the type of plant protein did not significantly influence the growth rate of L. monocytogenes in PBMAs. The presented model PMBA allows to vary the concentration of undissociated organic acids (lactic acid and acetic acid) and other parameters (pH, a, NaCl). This allows determining effects of individual growth inhibiting parameters in a PBMA matrix at desired levels which would be impractical to test in industrially produced products.
单核细胞增生李斯特菌是植物性肉类替代品（PBMA）中备受关注的一种病原体。在各种条件下测试单核细胞增生李斯特菌在实际产品中的生长行为，需要筛选大量的条件和时间点，这既耗时又昂贵。现已开发出一种具有代表性的PBMA模型，可用于测试在不同生长抑制参数存在的情况下单核细胞增生李斯特菌的生长情况。为了尽量减少操作和一次性使用，采用小型化最大可能数（mMPN）方法对单核细胞增生李斯特菌进行计数，该方法与菌落形成单位（CFU）计数具有良好的相关性。该PBMA模型还针对一系列温度（7-15°C）、水活度（低至0.940，通过NaCl调节）以及乳酸和乙酸浓度（分别高达2.5 mM和6 mM未解离酸）进行了验证。对单核细胞增生李斯特菌菌株FBR017的生长进行了定量，并确定了动力学生长参数。除大豆外，还测试了其他植物蛋白来源，包括豌豆、小麦以及小麦/大豆组合。所有基质都能轻易支持单核细胞增生李斯特菌FBR017的生长，根据拟合数据确定的所有蛋白质类型的生长速率相似，这表明植物蛋白类型对PBMA中单核细胞增生李斯特菌的生长速率没有显著影响。所提出的PBMA模型能够改变未解离有机酸（乳酸和乙酸）的浓度以及其他参数（pH值、水活度、NaCl）。这使得在PBMA基质中以所需水平确定各个生长抑制参数的影响成为可能，而这在工业生产的产品中进行测试是不切实际的。
