Safety Evaluation of the High-Dose Intake of Heat-Killed Lacticaseibacillus paracaseiMCC1849 in Healthy Adults.

Heat-killed Lacticaseibacillus paracasei MCC1849 (MCC1849) is a postbiotic used as a functional food ingredient. It has been shown to affect immune regulation both in vivo and in several clinical trials. Based on a previous safety evaluation, the intake of MCC1849 by healthy adults did not raise safety concerns. However, the effects of high-dose intake have not been investigated. In this study, the safety associated with a high-dose MCC1849 was evaluated in 20 healthy adults for 4 weeks. The participants received 250 billion cells of MCC1849 per day. Safety evaluations included anthropometric and blood pressure measurements, hematological and biochemical tests, urinalysis, and adverse event monitoring. No clinical differences were detected in anthropometric measurements, blood pressure, or blood and urine parameters between the baseline and post-intervention measurements. No adverse events associated with MCC1849 intake were observed. In conclusion, an intake of 250 billion cells of MCC1849 per day for 4 weeks was found to be safe in healthy adults. These results suggest that the intake of MCC1849 is safe for use as functional foods, such as for immune-enhancing effects.