314 Modern Food Microbiology
Using culture media, 7–10 log reductions of a 5-strain mixture of E. coli 0157:H7, S. Enteritidis, and
L. monocytogenes were achieved after exposure at 4 or 25
◦ C in acidic EO water.
203 After a 10-minute
exposure, complete inactivation occurred. The water in this study had a pH in the range of 2.4–2.6,
ORP around 1,150, and free Cl 2 of 43–86 ppm.
Activated Lactoferrin (ALF, Activin)
As noted in Chapter 3, lactoferrin is a normal component of fresh milk that has been known for many
years to possess antimicrobial properties. It is a glyoprotein with a molecular weight of around 80,000
da. It occurs also in saliva, tears, and some other body fluids. Activin is a more potent antimicrobial than
plain lactoferrin, and it was developed by A.S. Naidu. In the activated form, lactoferrin is immobilized
on food-grade polysaccharides such as carrageenan and solubilized in a citric/bicarbonate buffer with
NaCl.
134 It has been accorded GRAS status by the U.S. Food and Drug Administration.
Contributing to its antimicrobial activity is its capacity to chelate Fe
2+ along with HCO
−
3 . It binds
to cell surfaces and has a high affinity for the outer membrane proteins (OMP) of Gram-negative
bacteria. Naidu characterizes AFL as a blocking agent that interferes with the adhesion of bacterial
cells to animal tissues.
135 It also inhibits growth and neutralizes endotoxins. Its activity against both
RNA and DNA viruses suggests that it also interacts with nucleic acids. It has been approved at a level
of 65.2 ppm for beef carcasses, and may be applied either as a mist or by spraying. It is not a cidal
agent but acts primarily by preventing pathogens from establishing a niche on meat surfaces. More
information can be obtained from reference 134.
A feline kidney cell culture was used to propagate a norovirus (feline calicivirus, FCV), and a monkey
kidney cell line was used to propagate poliovirus (PV). When feline kidney cells were incubated with
PCV either prior to or together with bovine lactoferrin, substantial reductions of FCV infections were
noted.
122 Lactoferrin bound to both cell lines and apparently prevented virus attachment. Lactoferrin
B (cationic peptide from the N-terminal domain of bovine lactoferrin) reduced FCV attachment but
not PV.
122
Ozone (O 3 )
This gaseous compound has been known for over 120 years to possess antimicrobial activity. Like
chlorine, it is a powerful oxidant, and is ca. 1.5 times more potent than chlorine. It is effective in
solution and in its gaseous form. Because it is more effective in killing Cryptosporidium parvum than
chlorine, its use in water treatment systems is increasing. It is normally supplied from ozone generators.
It leaves no residue after it reacts, but its antimicrobial activity is antagonized by organic matter.
The odor of ozone can be detected at around 0.01 ppm. The threshold limit for long-term human
exposure (set by the U.S. Office for Safety and Health Administration, OSHA) is 0.1 ppm/day/work
week but for short-term exposure, it is 0.3 ppm for 15 minutes.
214 The cell target for O 3 is the
membrane where it disrupts permeability functions. Ozone is GRAS for bottled water use, and for
use on a variety of fresh foods, but its strong oxidizing power does not recommend its use for red
meats. A typical concentration used is 0.1–0.5 ppm, which is effective against Gram-positive and
Gram-negative bacteria as well as viruses and protozoa.
108 Ozone is allowed in foods in Australia,
France, and Japan; and in 1997 it was accorded GRAS status in the United Stated as noted above.
Ozone has been shown to be effective in reducing pathogens on a number of food products, and
its effect on apple surfaces and the stem and calyx is shown in Figure 13–3 where E. coli 0157:H7
was killed much more efficiently on apple surfaces than on stem/calyx.
2 These investigators found
Using culture media, 7–10 log reductions of a 5-strain mixture of E. coli 0157:H7, S. Enteritidis, and
L. monocytogenes were achieved after exposure at 4 or 25
◦ C in acidic EO water.
203 After a 10-minute
exposure, complete inactivation occurred. The water in this study had a pH in the range of 2.4–2.6,
ORP around 1,150, and free Cl 2 of 43–86 ppm.
Activated Lactoferrin (ALF, Activin)
As noted in Chapter 3, lactoferrin is a normal component of fresh milk that has been known for many
years to possess antimicrobial properties. It is a glyoprotein with a molecular weight of around 80,000
da. It occurs also in saliva, tears, and some other body fluids. Activin is a more potent antimicrobial than
plain lactoferrin, and it was developed by A.S. Naidu. In the activated form, lactoferrin is immobilized
on food-grade polysaccharides such as carrageenan and solubilized in a citric/bicarbonate buffer with
NaCl.
134 It has been accorded GRAS status by the U.S. Food and Drug Administration.
Contributing to its antimicrobial activity is its capacity to chelate Fe
2+ along with HCO
−
3 . It binds
to cell surfaces and has a high affinity for the outer membrane proteins (OMP) of Gram-negative
bacteria. Naidu characterizes AFL as a blocking agent that interferes with the adhesion of bacterial
cells to animal tissues.
135 It also inhibits growth and neutralizes endotoxins. Its activity against both
RNA and DNA viruses suggests that it also interacts with nucleic acids. It has been approved at a level
of 65.2 ppm for beef carcasses, and may be applied either as a mist or by spraying. It is not a cidal
agent but acts primarily by preventing pathogens from establishing a niche on meat surfaces. More
information can be obtained from reference 134.
A feline kidney cell culture was used to propagate a norovirus (feline calicivirus, FCV), and a monkey
kidney cell line was used to propagate poliovirus (PV). When feline kidney cells were incubated with
PCV either prior to or together with bovine lactoferrin, substantial reductions of FCV infections were
noted.
122 Lactoferrin bound to both cell lines and apparently prevented virus attachment. Lactoferrin
B (cationic peptide from the N-terminal domain of bovine lactoferrin) reduced FCV attachment but
not PV.
122
Ozone (O 3 )
This gaseous compound has been known for over 120 years to possess antimicrobial activity. Like
chlorine, it is a powerful oxidant, and is ca. 1.5 times more potent than chlorine. It is effective in
solution and in its gaseous form. Because it is more effective in killing Cryptosporidium parvum than
chlorine, its use in water treatment systems is increasing. It is normally supplied from ozone generators.
It leaves no residue after it reacts, but its antimicrobial activity is antagonized by organic matter.
The odor of ozone can be detected at around 0.01 ppm. The threshold limit for long-term human
exposure (set by the U.S. Office for Safety and Health Administration, OSHA) is 0.1 ppm/day/work
week but for short-term exposure, it is 0.3 ppm for 15 minutes.
214 The cell target for O 3 is the
membrane where it disrupts permeability functions. Ozone is GRAS for bottled water use, and for
use on a variety of fresh foods, but its strong oxidizing power does not recommend its use for red
meats. A typical concentration used is 0.1–0.5 ppm, which is effective against Gram-positive and
Gram-negative bacteria as well as viruses and protozoa.
108 Ozone is allowed in foods in Australia,
France, and Japan; and in 1997 it was accorded GRAS status in the United Stated as noted above.
Ozone has been shown to be effective in reducing pathogens on a number of food products, and
its effect on apple surfaces and the stem and calyx is shown in Figure 13–3 where E. coli 0157:H7
was killed much more efficiently on apple surfaces than on stem/calyx.
2 These investigators found