206 ◾ Fundamental Food Microbiology
3. Many isolates from infections have not been identified correctly to the genus and species
levels by modern genetic techniques. By biochemical fermentation pattern only, it is difficult
to identify the genus and species of an isolate in many situations.
The incidence of health hazard from beneficial bacteria, even with all the abuses, is very low. If
we consider other beneficial attributes, such as the use of antibiotics in the treatment of diseases,
the incidence of health risk is much higher. Considering this, it is justifiable to assume that true
food-grade lactic acid bacteria are safe.
Bioengineered probiotics carrying foreign genes also raise several concerns about their safety,
most importantly, the consequences of prolonged consumption of probiotics that are carrying
adhesion and invasion genes of pathogens. It is also not known whether individuals with suppressed
immunity will respond differently than healthy persons. The most important consideration in the
use of probiotics should be “do the benefits outweigh the ill effects?” Nevertheless, it is essential
to screen probiotics for their safety or long-term health effects prior to their use. 16 Guidelines
developed by the FAO (Food and Agriculture Organization) of the World Health Organization
(WHO) 17 should be followed: (i) identification of the probiotics at the genus, species, and strain
level; (ii) functional characterization using in vitro and/or animal testing; (iii) safety assessment
using in vitro cell culture and animal models; (iv) efficacy assessment in a human trial (double
blind study); and (v) effectiveness assessment in humans in comparison with a specific treatment
under a specific condition. In addition, probiotics should be labeled properly, specifying its genus,
species, and strain; bacterial counts at the end of shelf life; storage condition; manufacturer contact information, etc. 8
Probiotics, Prebiotics, and Synbiotics 14
Probiotics
The term “probiotics” was initially used with no specific definition. In 1989, Fuller 1 defined
the term as products containing living microorganisms that on ingestion (by humans, animals,
and birds) in certain numbers exert health benefits beyond inherent general nutrition. In this
statement, several requirements were included, such as the microbial cells should be alive and
consumed in high numbers (usually 10 9 cells/day). But it did not include which microorganisms (only intestinal or others) should be used and consumed for how long (daily as a preventative or for two or more weeks as a curative). It indicates that the consumption should produce
health benefits as judged by scientific clinical studies by reputed and independent research
groups and results published in peer-reviewed journals (not just a claim by somebody). It also
does not specify that the mechanisms by which the health benefits are produced should be
explained. In the status summary, as discussed before, these aspects have been specifically
included.
In recent years, several studies have shown that some specific health benefits can be achieved
by also consuming products containing dead cells or cell components of beneficial bacteria (e.g.,
immune modulation). It has to be decided in the future whether they also constitute probiotics. In
order to consider a new microorganism as probiotic or as a new probiotic functional food, the following properties must be known: (1) source or origin, (2) resistance to pH and bile salts, (3) adhesion and colonization, (4) competitive exclusion of pathogens, (5) immune regulation, (6) safety,
(7) stability to food processing conditions, (8) sensory assessment, (9) consumer acceptance, and
(10) efficacy assessment through human clinical trials. 18
3. Many isolates from infections have not been identified correctly to the genus and species
levels by modern genetic techniques. By biochemical fermentation pattern only, it is difficult
to identify the genus and species of an isolate in many situations.
The incidence of health hazard from beneficial bacteria, even with all the abuses, is very low. If
we consider other beneficial attributes, such as the use of antibiotics in the treatment of diseases,
the incidence of health risk is much higher. Considering this, it is justifiable to assume that true
food-grade lactic acid bacteria are safe.
Bioengineered probiotics carrying foreign genes also raise several concerns about their safety,
most importantly, the consequences of prolonged consumption of probiotics that are carrying
adhesion and invasion genes of pathogens. It is also not known whether individuals with suppressed
immunity will respond differently than healthy persons. The most important consideration in the
use of probiotics should be “do the benefits outweigh the ill effects?” Nevertheless, it is essential
to screen probiotics for their safety or long-term health effects prior to their use. 16 Guidelines
developed by the FAO (Food and Agriculture Organization) of the World Health Organization
(WHO) 17 should be followed: (i) identification of the probiotics at the genus, species, and strain
level; (ii) functional characterization using in vitro and/or animal testing; (iii) safety assessment
using in vitro cell culture and animal models; (iv) efficacy assessment in a human trial (double
blind study); and (v) effectiveness assessment in humans in comparison with a specific treatment
under a specific condition. In addition, probiotics should be labeled properly, specifying its genus,
species, and strain; bacterial counts at the end of shelf life; storage condition; manufacturer contact information, etc. 8
Probiotics, Prebiotics, and Synbiotics 14
Probiotics
The term “probiotics” was initially used with no specific definition. In 1989, Fuller 1 defined
the term as products containing living microorganisms that on ingestion (by humans, animals,
and birds) in certain numbers exert health benefits beyond inherent general nutrition. In this
statement, several requirements were included, such as the microbial cells should be alive and
consumed in high numbers (usually 10 9 cells/day). But it did not include which microorganisms (only intestinal or others) should be used and consumed for how long (daily as a preventative or for two or more weeks as a curative). It indicates that the consumption should produce
health benefits as judged by scientific clinical studies by reputed and independent research
groups and results published in peer-reviewed journals (not just a claim by somebody). It also
does not specify that the mechanisms by which the health benefits are produced should be
explained. In the status summary, as discussed before, these aspects have been specifically
included.
In recent years, several studies have shown that some specific health benefits can be achieved
by also consuming products containing dead cells or cell components of beneficial bacteria (e.g.,
immune modulation). It has to be decided in the future whether they also constitute probiotics. In
order to consider a new microorganism as probiotic or as a new probiotic functional food, the following properties must be known: (1) source or origin, (2) resistance to pH and bile salts, (3) adhesion and colonization, (4) competitive exclusion of pathogens, (5) immune regulation, (6) safety,
(7) stability to food processing conditions, (8) sensory assessment, (9) consumer acceptance, and
(10) efficacy assessment through human clinical trials. 18