BACKGROUND OF THE INVENTION
The invention relates generally to the application of microbiocidal
substances to food products. More particularly, the invention relates to the preparation
and the use of non-volatile microbiocidal substances as agents for the treatment
of food products.
The preservation of perishable products has been, and continues
to be, the focus of considerable commercial interest. By extending the shelf life
of a food product, economic value can be added to that food product. Approaches
to this end are many and varied (e.g., tight control of storage conditions, packaging,
post and in situ applications of preservatives) and various combinations
of these and other techniques are known and in practice to one extent or another.
In the context of one particular group of food products,
namely baked goods (e.g., muffins, crumpets, scones, bagels, cookies, breads, etc.),
all of the above techniques are in use. For example, baked goods can be placed in
frozen or refrigerated storage, covered with anaerobic packaging, and/or supplemented
by the addition of preservatives. When such preservatives are used, the preservative
can be added to either a batter or a mix from which the baked goods are prepared.
Also, the preservative can be applied to finished baked goods. With respect to the
finished baked goods, application of a small amount of the preservative can extend
the shelf life of the baked goods from a typical 6-8 days to an extended 14-16 days
when all other conditions (e.g., packaging, storage conditions), are equal. These
preservatives can include a wide variety of substances (i.e., microbiocidal substances,
antimicrobial substances, etc.) such as acetic acid, carbonic acid, mixtures thereof.
The nature of conventional microbiocidal agents and their
application requires elaborate and costly equipment to be used in order to accommodate
them. The additional measures required during the design, fabrication, installation
and use of equipment to be used with such substances can decrease the efficiency
and increase the cost of a microbiocidal application process. For example, in order
to use volatile substances, the following must be observed: explosion-proof components
must be used, adding tremendous cost to the application system; specific procedures
must be observed when storing the volatile gases, such storage oftentimes occurring
off-site and out of the direct control of the supplier of the volatile substances;
and detailed control and strict systems must be implemented to prevent leakage and
prevent exposure to those in working with the volatile substances. The leakage of
volatile substances can pose a significant risk to plant personnel.
It would be beneficial if the use of volatile substances
as microbiocidal agents could be reduced or eliminated. Further, it would be desirable
to provide a microbiocidal agent food treatment system that uses a non-volatile
substance as the microbiocidal agent.
Thus, a method for providing treatment to a food product
with a nonvolatile gas would be highly desirable since such a method would eliminate
the need for a volatile gas in the treatment process.
discloses an aerosol spray apparatus in the form of an aerosol can containing
a liquid disinfectant composition comprising an antimicrobial agent, for example,
hydrogen peroxide, and a flash vaporization component, for example, ethanol. The
aerosol can contains a gaseous propellant such as carbon dioxide.
A nozzle arrangement is employed of a kind in which manual
operation of a lever or push button opens the nozzle and causes the liquid to be
dispensed under the pressure of the gaseous propellant. The flash vaporization component
vaporizes on release of the pressure, thus causing the antimicrobial agent to atomise.
discloses a liquid composition for the cleaning of fruit and vegetables.
The composition is applied as a liquid and may include lactic acid.
SUMMARY OF THE INVENTION
According to the present invention there is provided a
method of treating a food product, comprising the steps of
providing a non-volatile liquid microbiocidal agent;
atomising the non-volatile liquid microbiocidal agent;
combining the non-volatile liquid microbiocidal agent with a carrier gas to form
a non-volatile microbiocidal agent-carrier gas formation;
heating the atomized non-volatile liquid microbiocidal agent so as to vaporize it
prior to applying the non-volatile microbiocidal agent;
delivering the non-volatile microbiocidal agent-carrier gas formation to application.equipment;
applying the non-volatile microbiocidal agent-carrier gas formation with the application
equipment to the food product.
Various other features, objects and advantages of the present
invention will be made apparent from the following detailed description and the
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are disclosed with reference
to the accompanying drawings and are for illustrative purposes only. The invention
is not limited in its application to the details of construction, or the arrangement
of the components, illustrated in the drawings. The invention is capable of other
embodiments or of being practiced or carried out in other various ways.
The drawings illustrate at least one mode presently contemplated
for carrying out the invention.
In the drawings:
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
- Figure 1 illustrates a schematic flow diagram of a process for preparing a baked
- Figure 2 illustrates a schematic flow diagram of another process for preparing
a baked food product; and
- Figure 3 illustrates a schematic flow diagram of one treatment fluid generation
system that may be used with the present invention;
Although the present invention is described below in the
context of applying a treatment fluid containing a preservative (e.g., a mixture
of carbon dioxide and a non-volatile microbiocidal substance) to a baked good, the
invention can also be employed with, and has applicability to, many different application
Referring to Figure 1, an outline 2 is illustrated for
preparation of commercial quantities of a food product, namely a baked good (e.g.,
muffin, crumpet, scone, bagel, cookie, bread). Batter is prepared and then poured
into molds that are either carried on, or form a part of, a conveyor mechanism.
The conveyor mechanism moves the batter through a baking zone in which the batter
is fully baked.
Upon leaving the baking zone, the baked good is de-molded,
typically onto a second conveyor mechanism. The de-molding procedure typically deposits
the baked goods upon the second conveyor mechanism such that the baked goods are
arranged in an indexed array. The indexed array of baked goods are then conveyed
through a cooling tunnel to bring the baked goods to a temperature appropriate for
packaging (e.g., room temperature or slightly above).
In some instances as illustrated in Figure 1, prior to
packaging, the baked goods will pass through a treatment apparatus. Prior to encountering
the treatment apparatus, the baked goods are assembled into batches. In batches,
the baked goods are transported through the treatment apparatus where a treatment
fluid containing a preservative is applied to an external surface of the baked goods.
Typical preservatives can include a wide variety of substances (i.e., microbiocidal
substances, antimicrobial substances). Preservatives have the ability to radically
reduce the pH of food products and, as such, can eradicate and/or eliminate bacteria
present within the food product. The treatment fluid can include a preservative
or a mixture containing the preservative. For example, a vaporized mixture of carbon
dioxide and an application agent can be employed as the treatment fluid.
In other instances, as illustrated by outline 4 in Figure
2, placement of the cooling tunnel and the treatment apparatus are reversed. In
other words, the baked goods are de-molded, assembled into batches, treated with
the treatment fluid, cooled, restored to the indexed array, and then packaged.
Figure 3 shows an example of an application agent preparation
system 100 that can be adapted for use with the present invention. System 100 is
capable of mixing a carrier gas and vaporized liquid with little, if any, entrained
droplets. In system 100, tank 101 holds liquid carbon dioxide, typically at about
2170 kPa (300 psig). Liquid carbon dioxide is transferred to vaporizer 102 and converted
to a gas substantially free of any droplets. The gas is then passed through pressure
reduction valve 103 and the pressure of the gas is reduced from 2170 kPa (300 psig)
to 790 kPa (100 psig). The gaseous CO2 is then transferred to heater
104 and heated to substantially the same temperature as the contents of mixing/separation
chamber 123 (e.g. 60°C (140° F)). Temperature control unit 126 coordinates
the temperature of heater 104 and of chamber 123. From heater 104, the gaseous carbon
dioxide at 790 kPa (100 psig) is transferred to mass flow meter 105, which is controlled
by flow control 106. As long as pump 107 is in proper operation, flow control 106
allows carbon dioxide to move from mass flow meter 105 into pipe 108. Pipe 108 divides
into pipes 109 and 110. While the amount of carbon dioxide each of pipes 109 and
110 will carry can vary to convenience, typically pipe 109 will carry about 10 percent
and pipe 110 will carry the remaining about 90 percent by weight of the carbon dioxide.
The stream of carbon dioxide passing through in pipe 110 can also pass through control
valve 111 before entering mixing antechamber 112.
Liquid acid, such as lactic acid, is removed from tank
113 through check valve 114 by the action of pump 115. When lactic acid is used,
the liquid lactic acid moves through line 116 and valve 117 into metering pump 107.
If atomization nozzle 120 is operational, then the liquid lactic acid is fed into
the atomization nozzle where the liquid lactic acid is atomized with carbon dioxide
delivered to the nozzle through line 109. If atomization nozzle 120 is not operative,
then the liquid lactic acid is returned to tank 113 by way of line 118 and check
Atomized lactic acid is transferred from atomization nozzle
120 into the upper section of mixing/separation chamber 123 in which it is vaporized
by contact with carbon dioxide delivered from mixing antechamber 112 through orifice
plate 121. The carbon dioxide delivered from line 110 into antechamber 112 passes
through pressure reduction valve 111 in which the pressure of the carbon dioxide
is reduced from 790 kPa (100 psig) to about 135 kPa (5 psig). The pressure of the
atomized lactic acid as delivered to mixing/separation chamber 123 is also about
135 kPa (5 psig). The temperature, pressure and volume of carbon dioxide introduced
into the upper section of mixing/separation chamber 123 is sufficient such that
the atomized lactic acid is essentially completely vaporized upon contact with it.
Atomization nozzle 120 passes through antechamber 112 and
orifice plate 121, and opens into the upper section of mixing/separation chamber
123. Atomization nozzle 120 can extend into the upper section of mixing/separation
chamber 123 to any convenient length, but typically the end of the nozzle is flush
with or extends only a short distance beyond orifice plate 121.