盐(NaCl)与高血压和冠心病的发展风险有关,所以它的消费应该是有限的。然而,盐通过控制不良微生物在食品的质量和安全中起着关键作用。由于研究主要集中在盐对乳酸菌(LAB)组的整体计数的影响,我们尚未了解盐胁迫如何单独影响菌株以及它们之间的相互作用。在这项研究中,我们表征了氯化钠(NaCl)和氯化钾(KCl)对31个LAB菌株生长和酸化的影响。此外,我们评估了盐对93个随机成对菌株组合的影响。菌株和共培养物在3%NaCl下测试,5%NaCl,使用自动化方法和图像分析在固体培养基上和3%KCl。结果表明,在5%NaCl下,LAB的生长显着降低了68%(p<0.0001)。对于共同文化,在5%NaCl下观察到高达57%的减少(p<0.0001)。然而,酸化受盐胁迫影响较小,无论是单一文化还是共同文化。此外,与NaCl相比,KCl对生长和酸化的影响较小。的确,一些菌株在3%KCl时生长显着增加,如乳酸乳球菌亚种。乳酸74310(23%,p=0.01)。更重要的是,共培养似乎比单一培养更有弹性,对盐胁迫的反应更多样化,因为检测到了几种抑制盐对酸化和生长的显着影响的情况。我们的研究结果强调,虽然盐可以调节微生物的相互作用,这些后者还可以减弱盐对LAB的影响。
Salt (NaCl) is associated with a risk of hypertension and the development of coronary heart disease, so its consumption should be limited. However, salt plays a key role in the quality and safety of food by controlling undesirable microorganisms. Since studies have focused primarily on the effect of salts on the overall counts of the lactic acid bacteria (LAB) group, we have not yet understood how salt stress individually affects the strains and the interactions between them. In this study, we characterized the effect of sodium chloride (NaCl) and potassium chloride (KCl) on the growth and
acidification of 31 LAB strains. In addition, we evaluated the effect of salts on a total of 93 random pairwise strain combinations. Strains and co-cultures were tested at 3% NaCl, 5% NaCl, and 3% KCl on solid medium using an automated approach and image analysis. The results showed that the growth of LAB was significantly reduced by up to 68% at 5% NaCl (p < 0.0001). For the co-cultures, a reduction of up to 57% was observed at 5% NaCl (p < 0.0001). However,
acidification was less affected by salt stress, whether for monocultures or co-cultures. Furthermore, KCl had a lesser impact on both growth and
acidification compared to NaCl. Indeed, some strains showed a significant increase in growth at 3% KCl, such as Lactococcus lactis subsp. lactis 74310 (23%, p = 0.01). More importantly, co-cultures appeared to be more resilient and had more varied responses to salt stress than the monocultures, as several cases of suppression of the significant effect of salts on
acidification and growth were detected. Our results highlight that while salts can modulate microbial interactions, these latter can also attenuate the effect of salts on LAB.