Table 1.

Evolvement of the concept “postbiotics”.

Concept	Date	Bacterial Strains Tested	Main Findings	Reference
Paraprobiotics or ghost probiotics	2009	Multiple	The health benefits of probiotics can be achieved without the risks related to administration of a live organism.	[47]
Paraprobiotics or ghost probiotics	2011	Multiple	Propose the new term “paraprobiotic” to refer to the inactivated microbial cells or cell fractions.	[48]
Paraprobiotics or ghost probiotics	2016	Lactobacillus	Paraprobiotic Lactobacillus affects intestinal functionality due to the brain-gut interaction.	[49]
Paraprobiotics or ghost probiotics	2018	Lactobacillus	L. paracasei MCC1849 improves resistance to common cold infections in vulnerable individuals and maintain a favorable emotional state.	[50]
Paraprobiotics or ghost probiotics	2018	Multiple	Paraprobiotics could be safe alternatives to probiotics in preterm neonates.	[51]
Paraprobiotics or ghost probiotics	2018	Multiple	Review the effectiveness of paraprobiotics for the prevention or treatment of virally-induced infections.	[60]
Para-psychobiotic	2017	Lactobacillus	Para-psychobiotic Lactobacillus gasseri CP2305 regulates stress responses depending on specific cell component(s).	[52]
Metabiotics	2013	Multiple	The concept, function and advantages of metabiotics.	[53]
Metabiotics	2020	L. rhamnosus	The isolated probiotic L. rhamnosus MD 14 generated metabiotics exhibiting antigenotoxic and cytotoxic effects against colon cancer.	[54]
Tyndallized probiotics	2016	L. rhamnosus	L. rhamnosus IDCC 3201 tyndallizate has potential for treating atopic dermatitis.	[57]
Tyndallized probiotics	2017	Multiple	Gelatin tannate and tyndallized probiotics can be used to restore the gut barrier physiological functions and prevent dysbiosis.	[58]
Tyndallized probiotics	2019	Multiple	Tyndallized bacteria and purified components confer probiotic properties.	[4]
bacterial lysates	2018	Multiple	Bacterial lysates minimize the incidence of recurrent respiratory infections in children and adults when orally administrated.	[59]