Note: Descriptions are shown in the official language in which they were submitted.
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ODOR INHIBITING PET LITTER
TECHNICAL FIELD
The invention generally relates to animal hllsb~ndry, especially to m~teri~l for15absorbing moisture from waste products. The invention di~c]ose,s a clay based pet litter
in which a b~cteri~l elpmp~nt is mixed with certain types of clay to inhibit formation of
ammonia from urea for a period of several days.
BACKGROUND ART
20House.hold pets often are kept indoors and deposit their wastes in an absorbent
composition, referred to as pet litter or cat litter. Half a century ago, indoor pets
commonly used a box of sand to receive their wastes. Since then, pet litter has evolved
into a specialty market, which began with the use of industrial absorbents. Today, a
suitable base m~teri~l for producing pet litter is clay, which is ~-e~ ellsive, absorbs
25liquids, and is easily disposed of, such as in the garden, or in the trash. Many clays are
used as pet litters because of their e~cellPnt absorptive qu~lities. Among them,
attapulgite clay, which is hydrous m~gn~ium ~h....i"l.." .cilic~te, is one of the most
commonly used pet litters. Simil~rly, fuller's earth is a combin~tion of attapulgite clay
and bento~,i~, clay.
30Bentonite, which is a montmorillonite clay, is formed of hydrous m~gnPsillm
~h.i";..~.." silicate and is widely used as pet litter. Its two common forms, sodium
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bPntonitç. and c~lcillm bentonite, are distinguished by having either sodium or calcium
cations. ~1cil1m bçnt~nit~, also known as southern bentonite, is an acid activatable
clay that can be treated with hydrochloric acid or sulfuric acid to ~ignifi(~nt1y increase
its surface area and enhance it absorptive plopellies. It is the better absorbent of the
S two. Sodium be.,~o~ has the ability to swell several times and forms gel-like masses
in water, while calcium bel-~onil~ swells much less. Sodium bP.ntonite also is known
as Wyoming or weslelll b~ n;lP
Two other common pet litters are kaolin, or china clay, and se~iment~ry opal
clay ~ es. Kaolin is a hydrous ~ll1minllm silicate of the ~o1initP mineral group,
l0having the formula Al2O32SiO22H2O. A commercial opal clay mixture contains
se~iment~ry opal. Opal clay contains about 20 percent more silicon dioxide than is
found in benlol-;lP and has high porosity, which provides a high absorption capacity.
Both clays are commonly sold as pet litter.
The process of producing a clay based pet litter is similar with any type of clay
15m~tçri~1 Raw clay, which typically contains about 35 percent water, is mined from an
open pit. Large earth movers deliver the clay to trucks, which haul it to a plant where
it is dried in a kiln and crushed in several stages. During procçssing, different clays
and other ingredients can be b1en~ed to produce a pet litter having special qu:~lities,
such as clumpability or odor control. After b1çn~ing, the product granules are sorted
20by screening into various siæs. The final pet litter can be a l"ib~ of sizes, which is
more absorbent than when all granules are the same size.
The usefulness and pçrform~nce of ordinhl~y clay or other litter materials has
been improved in three general areas. First, it has been discovered that litter is easier
to keep clean if wet particles agglomerate or clump together, making it easier to remove
25the spent litter and waste products from the unspent litter. Second, several
e, ;ll~çnters have added chPmi~1 or biological agents to litter in an attempt to digest
the animal wastes or otherwise reduce odors. Along these same lines, litter can be
scented to mask odor. Third, special litter m~t~ 1c have been developed that areespecially absorbent. Several patents have issued in each of these areas.
30The first type of patents disclose several tech~iques for clumping litter particles
when wetted. For example, U.S. Patent 5,216,980 to Kiebke combinPs gr~n~ r clay
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with a gluten co~ -g hydrophilic media. U.S. Patent 5,183,010 to Raymond et al
uses potato starch, gum, or polyvinyl alcohol to bind wet particles, plus boron to
accelerate hardening. U.S. Patent 5,152,250 to Loeb mixes gr~n~ r litter with grain
flour to cause ~lomP.r~tion and minPr~l oil to cause the flour to adhere to the grains.
U.S. Patent 5,094,189 to Aylen et al adds potato starch to bel-lo~ clay. U.S. Patent
5,000,115 to ~ghes mPntion~ that certain natural bçntonite clays, alone, are c~r~blP
of cl--mpin~ when wetted. U.S. Patent 4,685,420 to Stuart uses a polymer in clay to
form a gelled agglomerate when wetted.
These and other methods of causing spent litter to clump offer an improvement
over non-clnmring litter. Rec~ e only wet litter forms clumps, the spent litter and the
waste cont~inP.d by it can be comrletely removed from the litter box, while permitting
unused litter to remain behind. Thus, clumping litter is efficiPnt and economical,
allowing both solid and liquid waste to be removed from the litter box without requiring
that the balance of clean litter also be removed. Further, clumps are easy to remove
from a litter box, which makes the cle~ning job much more ple~nt and raises the
expect~tion that this job will be done more frequently. Consequently, it is expected that
clumping litter results in decreased waste odor in the home, due to the frequent and
complete cl~.~nings.
The second type of patents add a chPmic~l agent that is intended to reduce odor.For example, U.S. Patent 5,303,676 to Lawson combines bentonite with sodium
bicarbonate or potassium bicarbonate coated with a mixture of mineral oil and siliceous
m~teri~l to deodorize the litter. ZnO can be added as a bact~rici~le U.S. Patent4,607,594 to Thacker combinPs bçl-lol-;le with perlite, which has been treated with
carbonate, bicarbonate or hydrogen phosph~te U.S. Patent 4,517,919 to Benjamin et
al adds undecylenic acid, a f~m~icille, to ~e.~ ilr or other base m~te~l U.S. Patent
4,494,481 to Rodriguez et al uses transition metal salts in ~e litter box to control urine
odor. U.S. Patent 4,459,368 to Jaffee et al mixes c~lc;llm be.nto~itP with calcium
sulfate dihydrate to control odor. U.S. Patent 4,437,429 to Gol~s~in et al uses æolites
to control odor in be,ntonite U.S. Patent 3,941,090 to Fry adds cedar bound withalfalfa. U.S. Patent 3,916,831 to Fisher uses popcorn as litter, wi~ added bactericides.
U.S. Patent 3,892,846 to Wortham uses Al, Zn, Sn, Ca or Mg salt of an hydroxamic
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acid in litter to resist odor by inhibiting bacterial decomposition of urea to ammonia
when wetted by urine. U.S. Patent 3,789,797 to Brewer et al combines bçntonitP. and
aLfaLfa, which supplies chlorophyll. U.S. Patent 3,636,927 to Baum adds c~mph~n~compounds, which smell like cedar oil. U.S. Patent 4,844,010 to Duch~rme et al uses
cyclodextrin in clay to absorb nitrogenous compounds. U.S. Patent 4,704,989 to
RosPnfel~l adds absorptive rn~tP.ri~l~ to clay litter, deodori7~r~ and bactericides. U.S.
Patent 4,671,208 to Smith adds limestollP to litter to neutrali_e urine and raise pH. U.S.
Patent 4,465,019 to Johnson adds dried citrus pulp to litter. Japan Patent 3044-822
discloses an animal litter composed of clay and a water in~r)lublP. chemical deodorant,
which may be an organic acid and its salt. Japan 3020-100 discl()ses use of bçl~lc/~ P,
zeolite, or cristobalite plus deodori7Pr EPO Publication 76,447 reduces ammonia
content of air in animal stalls by lowering pH, through addition of a mixture of urea
phosphate, phosphoric acid, sulfuric acid or alkali metal hydrogen sulphate and an
organic acid. The low pH suppresses pathogenic bacteria by encouraging growth ofacidophilic O~ llS such as lactobacilli, increasing lactic acid content. EPO
Publication 39,522 m~mlf~ctures litter from cellulosic fibers, ppllpti7pd~ with added
fungicides and bactericides.
These chemic~l agents may achieve success, although it appears that some could
be expensive and others might require large concentrations to effectively treat any
signific~nt volume of animal wastes. Some of the chPmi~ls might cause environment~l
problems, especially if allowed to build up by disposal in a dump site or garden over
a long period of time. For this reason, alone, the use of deodorizers, bactericides,
fungicides, acids, metal salts, and perhaps other similar m~tPri~l~ appears to be a poor
choice. In addition, pets walk through the litter box. Thus, these chernicals will be in
contact with the pet's feet for s~lbst~nti~l periods of time, which might cause irritation
or other health problems. As pets groom themselves, the chemic~lC may in ingested.
Further, the pet may track these chPmir~ls through all areas of the house, spreading
potential problems to human inhabitants, as well.
A few patents have aLlelLpLed to use biologic agents to reduce odors. For
e7~mplP, U.S. Patent 5,154,594 to Gamlen combines clay with digèstive bacteria to
break down the waste. Japan Patent 2154-629 combines multiple types of bacteria on
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a sawdust growth mPflillm to break down ammonia, which is a bacterial decomposition
product and major odor component, and other excrement and thereby prevent odor.
Japan Patent 1085-125 discloses the combin~tion of sawdust and thermophilic bacteria
on the floor of a cattle shed to control odor. The ~ Lu~ is placed in a compost shed
for several weeks to produce mature compost. Soviet Union 1,091,889 discloses ananimal bedding made of composted manure. Thermophilic bacteria in the manure cause
an increased temp~ that kills disease microorg~nicms. After composting, the
manure is reused as beddin~ Denmark Patent 86,908 combinPs cellulose and
coccidillm-lk~d..lg agent plus a protein rich m~ri~l These biologic agent patents
seem unlikely to be completely successful, since composting or digesting wastes
produces odors.
The third type of patent, in which absorbency is increased, is represented by
United States Patent No. 4,657,881 to Crampton, which makes highly absorptive cat
litter from clay fines that are compacted and then broken into larger particles.Absorbency is increased by adding an antideposition agent, which might include
Wyoming bPntonite, which is known to form a gel when wetted. The content of United
States Patent No. 4,591,581 to G~.,ploll is similar. L~pro~ g absorbency would be
exrectPd to make a litter more efficient, since liquid wastes might be captured in the
granular m~te~i~l Mther than being allowed to pool at the bottom of the litter box.
These many approaches to ilJlploved h~ndling of animal wastes demonstrate that
controlling odor of animal wastes is long st~n-lin~ problem. Some of the approaches
deal with specialized problems that are unlikely to be reproduced with home litter
boxes. For example, those treatment.~ directed to cattle barns are dealing with cellulose
based wastes, since cattle are he.livol~s. Ln contrast, home pets like dogs and cats
consume a mos~Lly protein diet and their wastes tend to be far more putrid. Those
techniques that claim to digest wastes are unlikely to be a full household cure, since the
digestion process itself produces ammonia, which is a source of strong obnoxious odor
from wastes. Thus, it appears a hou~ehold litter that is odor free or at least can delay
~signific~nt odor formation for a substantial tirne period is yet to be developed.
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It would be decir~blP to have a litter or a tre~tmPnt for litter that prevents
form~tion of odor causing subsl~n~çs Digestive schemes alone are unlikely to prevent
odor, since digestion produces odor if only for a short time.
Further, it would be desirable to have a litter that can prevent formation of
5 obnoxious odor without requiring an added fragrance to mask various odors thatordinarily develop. The ~tl(lition of a fragrance to litter, for the purpose of covering bad
odors, often is not a s~ticf~ctory solution since the odor contimles to exist in the
background of the fragrance. Of course, animal wastes have an immP~i~tç odor that
a mild fragrance might cover. It is subsequently developed odors, such as ammonia,
10 that tend to be most obnoxious and permeating These are the odors that are most
important to prevent.
~ imil~rly, it would be de~cir~hlp to have a litter or a tre~tment for litter that
prevents form~tion of odors for at least a full day and preferably longer. Even the most
attentive pet owner can be delayed from promptly ell~pLyillg a used litter box.
15 Ordinarily, the odors from a used litter box become obnoxious quite soon after the use
and soon can perme~tp~ a house. Therefore, if these odors are substantially elimin~ted
for one or two days, or more, the ~mbiçnce of the house is greatly improved.
Moreover, it would be desirable to combine an odor free litter or treatment for
litter with a clllmping litter, both to simplify emptying the spent portion of litter from
20 the litter box and to m~int~in the waste in contact with the treated litter for effective
odor prevention.
Another dçsir~hlç goal is to control or suppress odor while using only a small
amount of active agent. The chP.mic~l or biological tre~tment.c known in the prior art
might involve prohibitive expense. Further, it would be undesirable to add significant
2~ qll~ntitiPs of any sort of agent to est~hli.chP.d litters such that they might change the
character of the litter material, resulting in the agent being tracked about the house on
the pet's feet.
To achieve the foregoing and other objects and in accordance with the purpose
of the present invention, as embodied and broadly described herein, the product and
30 method of this invention may comprise the following.
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DISCLOSURE OF INVENTION
Against the descrihed background, it is therefore a general object of the
invention to provide an improved odor inhibiting animal absorbent or tre~ttnto.nt of
animal absorbents suited for use in home litter boxes, in which animal wastes are
5 p~Gvellled from producing obnoxious odors.
A more specific object is to provide an animal absoll,Gll~ that can delay odor
form~tion for at least one day.and preferably longer, after the waste contacts the
absorben~
Another object is to provide an odor inhihiting animal absorbent that can work
10 in cnmhin~tion with a clllmring litter, so that the absorbent and the animal wastes are
m~int~ined in operative contact.
A further object is to create a deodorized animal absorbent that is safe for usein a litter box, with respect to both the pet and hnm~n~ in the house.
Still another object is to provide a deodori7ing tre~tmçnt for pet litter that
15 requires very little additive or treating agent. A low concentration of additive or
treating agent is desirable to make the tre~tm~nt affordable and prevent the pet from
tracking the additive or agent.
ition~l objects, advantages and novel features of the invention shall be set
forth in part in the description that follows, and in part will become app~clll to those
20 skilled in the art upon çx~min~tion of the following or may be learned by the practice
of the invention. The object and the advantages of the invention may be realiæd and
~tt~ined by means of the instrllm~nt~litif~s and in comhin~ti-)n~ particularly pointed out
in the appended claims.
According to the invention, an odor lGl~dillg pet litter is formed of an absorbent
25 composition and a urease negative bacterial culture combined with the absorbent
composition, in an effective amount to inhibit growth of urease positive b~cteri~ when,
in use, the absorbent composition is wetted with animal waste conl~ g urea.
According to another aspect of the invention a method of suppressing production
of odor in pet litter is achieved by applying to a pet litter an effective amount of a
30 urease negative b~rter~
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The accompanying drawing, which is incorporated in and forms a part of the
specification illu~ ~s the performance of a preferred embodiment of the present
invention, and together with the description, serves to explain the principles of the
invention. In the drawing:
BRIEF DESCRIPIION OF THE DRAVVING
Figure 1 is a graph showing ammonia content of spent pet litter over time,
comparing litter treated according to this invention with untreated litter.
BEST MODE FOR CARRYING OUT THE INVENTION
The invention is an odor inhihiting pet litter, a method of treating pet litter
m~tPri~lc to achieve odor inhibition, and a litter box col-s~h-;,~g the treated pet litter
m~t~ri~l The products and methods of this application are based upon use of a urease
negative organism that delays decomposition of solid and liquid animal wastes, with the
15 result that ammonia is not formed and released with the typical frequency of such
wastes decomposing in nature. Ammonia is believed to be the chief cause of obnoxious
odors from liquid animal wastes aging in a litter box. During the period of prevention
or delay, the urease negative organism effectively plcve~ formation of obnoxious odor.
Org~nicm.~ of this type are effective in low concentrations against the volumes of waste
20 typically deposited in a litter box. In ~d~litiQn~ such org~ni~mc are not harmful to
~nim~lc or hnm~n~
In another aspect, the invention is an intPr~ctive system of urease negative
org~ni~m~ and buffer means. When the system is subjected to wastes, such as acidic
urine, it m~int~in~ pH in a range favoring the organism. The buffer means may be the
25 pet litter m~teri~l, itself, especially when the litter m~teri~l is a smectite (swelling) clay,
such as sodium bentonite The preferred pH range is basic, especially around pH 7-9.
A further aspect of the invention is the interaction of the organism with
clumping pet litter m~teri~l~ Numerous clumping pet litters are known in the art,
including some that occur naturally and others that are man-made. A preferred
30 clumping litter is formed of a substantial concentration of sodium bel~to~ P, which is
naturally occurring and inherently gels or clumps when wet. When used with other
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clays or pet litter m~tP.ri~ls, the concçntration of sodium bentc)nit~P. must be at least about
fifty percent to realize the natural clnmping action. Because sodium bentQnitP is a
natural cl~lmping m~tPri~l and also is a s-lit~blP buffer, this single m~tPri~l is a preferred
choice. Further considerations are that sodium ~ ton;lr iS plentiful, in~pe~cive~ and
5 already has been used as pet litter for many dec~(1Pc It can be safely disposed of in
compost, in the garden, or in the trash.
Smectite clays are a group of minerals composed of units made up of two silica
tetrahedral sheets with a central ~ min~ oct~hpflral sheet. F~ch~nge~hlp cations are
found belween the silicate layers. The layers are stacked with oxygen atoms from each
10 layer being disposed in a common int~rme~i~te layer. The bonding between adjacent
oxygen atoms in the central layer is weak and results in cleavage between the units.
Polar molecules such as water can enter between units and expand the lattice structure.
Thus, the .smectite clays are swell easily in the presence of water or other polar
moleclllP.s. Some examples of smecliles are the dioctahedral smectites:
15 montmorillonit~, bei~P,llitP, and non~l~nile; and the trioct~hedr~l smectites: hectorite
and saponite.
A number of urease negative org~nicmC are known and are suitable for use in
a litter product. Among them are strains selected from group N streptococcus, such as
lactococcus lactis ssp. lactis, lactococcus lactis ssp. cremoris, and lactococcus lactis ssp.
20 lactis bio var diacetylactis; group D streptococcus, such as streptococcus faecium;
pediococcus such as pediococcus aci(~ ctici~ pediococcus cerevisiae, and pediococcus
pPntos~pceus; propionih~ctprium such as propionih~cterium .chP.rrn~nii and
propionibacterium freudenreichii; leuconostoc such as leuconostoc mesenteroides ssp.
cremoris and leuconostoc me,c~ eroides ssp. dextranicum; and lactobacillus such as
25 lactobacillus acidophilus and lactobacillus bulga~cus. Other nonspecific bacillus type
orE~nicmc of compost and soil origin also are c~n~id~tP.c
Urease negative strains belonging to the genus lactococcus, streptococcus,
pediococcus, propionibacterium, leuconostoc, lactobacillus, and non-specific unidPntifiPd
bacillus type urease negative org~ni.cmc of compost and soil origin were propagated in
30 sterile nntriçnt medium. The cultures were transferred thrice to activate the cellular
metabolism. A stPrili7P,d 12% solids medium was prepared by heating it to 170F to
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-10-
190F, holding for 45 minutes to l hour, and cooling to 90F. The org~nicmc wereinocnl~tP~ into this 12% solids mP(lillm The amount of inoculum used was one
percent. The cultures were incubated and neutralized at specific intervals to m~ximi7e
the cell population. At the end of the growth period, the cultures were cooled to 40
S to 50F. Then all the liquid cultures were blended and mixed with dry base cnnci~ting
of vegetable flour, carbohydrates, vegetable gum, and sodium montmorillonite. After
it is mixed, the entire doughy mass is extruded cold and dried at room ~,llpe,~
Notably, this p~pala~ion includes the spent growth me.dillm and byproducts of growth,
such as bacterial enzymes and other beneficial by-products. The culture preparation
10 thus prepared is mixed with the smectite clay, such as sodium montmorillonite, to
prepare a pet litter. An ~ltem~tive p~~ Lion is to apply the liquid culture pl~al~on,
after growth stage, by spraying it on the smectitp~ clay or other pet litter blend, inclu~ling
swelling smectite clays such as sodium montmorillonitP..
In the course of con~ucting these studies, it was discovered that the stimulant,15 yucca schi~igcra extract, had an exceptional stimulatory effect on the urease negative
bacteria, especially on propionibacterium species. This result was determined using
direct microscopic P.x~min~fion. However, even urease negative bacteria cultures grown
in growth medium without yucca schidigera extract exhibited odor inhibition in pet
litter. A control me~illm without any bacteria, but with yucca schidigera extract, even
20 when used at high concenl,~lion, could not inhibit odor in pet litter. Urease negative
bacteria grown in the presence of yucca schidigera extract exhibited significantly better
ability to inhibit odor in pet litter, as compared to urease negative bacteria grown
without this stimulant. Possibly the exceptional growth of bacteria in the presence of
yucca sçhi(lig~P.r~ extract leads to production of signific~ntly different bacterial by-
25 products. When the relative qu~ntities of other ingredients in the growth media werevaried, no similar advantage was found.
The term "treated litter" and the like will be used throughout to refer to pet litter
of any description to which urease negative org~nism.c have been applied, unless context
in~ic~tes otherwise.
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The term, "unllea~d litter" and the like will be used throughout to refer to petlitter of any description to which urease negative org~nicm.c have not been applied,
unless context in-lic~tes othen,vise.
The terms, "benP.fici~l org~ni.~ms," "ben~.fici~l culture" or the like, refer to urease
5 negative b.~cteri~ or cultures of same, unless context in(~ t~, othenvise.
The terms, "culture pl~t~aLion," "bacterial pl.~a,alion," "b.~cteri~l enzyme
culture additive" or the like refer to a urease negative b~ct~ri~ in combin~tion with
spent growth me~ium and growth by-products, such as enzymes and, optionally
depending on conte~t, solidifying and bulking agents, unless context inrli~tP.s otherwise.
EXAMPLE 1
A culture preparation for application to pet litter is prepared by first formulating
a basic m~tri~nt medillm Suitable ingredients include a protein source, such as sweet
whey, casein hydrolyzate, and autolyzed yeast extract; a carbohydrate source, such as
dextrose; buffers, such as disodium phosphate, monosodium phosph~te, and sodium and
15 bicarbonate; stimulants, such as powdered yucca schit~igera extract; and water. A 100
lb. mixture of m~ m is p~ ,d from the following ingredients, t;~Lplessed as weight
percent.
TABLE 1
Ingredient Percentage Typical P~e~elled
Range Range
SweetWhey 63.0 50 - 75 60 - 65
Autolyzed Yeast Extract 5.0 2.5 - 7.5 3 - 5
Dextrose 20.0 10 - 30 15 - 25
Disodium Phosphate 1.5 1 - 3 1.25 - 2.75
Monosodium Phosphate 3.0 2 - 5 2.5 - 4.0
Casein Hydrolyzate 5.0 2.5 - 7.5 3 - 5
Powdered Yucca Schidigera Extract 0.50 0.05 - 2.5 0.25 - 0.75
Sodiùm Bicarbonate 2.0 1 - 5 1.5 - 3
- -
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The ingredients are thoroughly blended and may be stored in dry form until ready for
use.
A liquid culture is prepared by reconstituting the medium at the rate of 12%
solids by weight in warm water. Next, using acid or base neutralizer, pH is adjusted
to 6.8 to 7Ø The mP~ m is heated with constant agitation to 190F and held at that
temperature for 40-45 minlltPs Then the medium is cooled to 90F and inoculated with
individual urease negative strains of lactococcus lactis ssp. cremoris, lactococcus lactis
ssp. lactis, lactococcus lactis ssp. lactis bio var diacetylactis, pediococcus cerevisiae,
pediococcus ~Cit~ rtiri~ pediococcus pPntos~Pce lc, streptococcus faecium,
propionih~cterium .chPrm~nii, propionibacterium freudenreichii, leuconostoc
mesentP.roides ssp. cremoris, leuconostoc mesçnteroides ssp. dextranicum, lactobacillus
acidophilus, lactobacillus bulgaricus, and non specific urease negative compost and soil
origin, ~mi~P.ntified mixed flora. The org~ ",c are allowed to grow until pH drops
to 5.8. Then, the cultl-res are neutralized to pH 6.2 using an ~lk~line neutralizer such
as sodium hydroxide, potassium hydroxide, or ammonium hydroxide. The process is
contin~led, often ten to fifteen times, until the pH no longer drops below pH 5.8. At
this stage, most of the mltri~.nt.c are exh~lstPcl and a sufficient population is established
in the medium The live cell count concclllldlion at this stage is approximately 2 to 5
billion org~nicmc per gram.
Next, the medinm is cooled to 50F by circulating cold water through cooling
tubes. The fully grown liquid culture is blended in a s~dlc vessel with dried
vegetable flours or vegetable flour and bentonite or other suitable dry material to bring
it to a doughy concictenry~ thereby producing a culture preparation. The cultureplc~ on is extruded, dried, and milled to the co~cictPncy of gr~nlllP.s or f~e, 200
mesh powder.
The dried bacterial prcpdrdLion is blended with smectite clay or other suitable
granular absorbent to form a treated pet litter. The dried bacterial prc~dld~ion can be
supplied as an independent additive, to be mixed with any selected pet litter, such as
by a pet owner or pet litter supplier. Simil~rly, the bacterial ~lc~lion can be mixed
with a suitable absorbent m~teri~l and supplied ac a treated pet litter product. It is
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simil~rly possible to offer a treated pet litter in a package that also serves as a litter
box.
These org~nicm.c have been tested individually and in combin~tion.c at the rate
of 0.1% to 5% by weight in sodium be~ e In a preli...;..~, y qualitative test, 300 gm
5 s~mrlPs of treated litter were prepared. Cat urine, from veterinary supply sources, was
added to each s~mrlç, and the s~mpl~s were allowed to sit at room ~lllpC.alUle for a
period of three weeks. Equivalent control s~mples con.ci.cted of untreated bentQnite. A
three member panel evaluated odor of all aged s~mrl~.s. The result was that the
s~mpl~s treated with urease negative bacteria had less odor than the control s~mples
10 Samples using a combin~tion of two species of urease negative bacteria showed still
lower odor. Samples treated with urease positive bacteria were found to have powerful
odor, stronger than the control .c~mrlec
Based upon this prelimin~ry showing of efficacy, further tests were run to
delel...;..e field efficacy and acceptance by ~nim~l.s and hnm~n.c All tests were
15 conducted using the culture pleL)a,ed according to F~x~mple 1.
EXAMPLE 2
Qualitative efficacy tests were contiuct~.d A seven to ten day test of animal
absorbents, with and without the benefici~l culture, was run in households having cats.
Sample A was ordinary sodium b~.ntQnit~ cat litter; Sample B was sodium bentonite
20 treated with 1% by weight of a culture p~p~lion of beneficial or~ni.sm.c, as prepared
in Fx~mrle 1. This high level of a pl~pa.~Lion of these or~ni.cm.c was used to
determine whether high levels would be accepted by cats. Seven households returned
bags of cat wastes removed from litter boxes of each sample. All cats used both
s~mples, showing that litter coJ~ i ng the culture preparation was accepted. Based on
25 weights of the returned bags of wastes, most of the cats pr~relled B.
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TABLE 2 -- CAT DROSS COLLECTION DATA
WEIGHT WEIGHT NUMBER OF PREFER
SAMPLE A SAMPLE B CATS
5 (lbs.) (lbs.)
3.6 4.0 2 B
0.8 1.1 1 B
2.4 6.0 3 B
1.3 1.5 1 B
0.8 1.3 2 B
3.8 5.1 3 A
3.8 4.0 2 A
TOTAL: 18.0 21.5 14 --
Further tests were con~-lctPd on the urine soaked clumps from the waste
collection bags:
ODOR TEST: S~mplPs A and B each consisted of a collection of variously
aged specimens, ranging from 0-10 days old. Each collection was kept in a bucket, and
the odor from the bucket was evaluated in gross. The urine clumps of Sample A were
20 pungent, repulsive, and ammoniacal. The urine clumps of Sample B had a mild
ferm~P.nt~tive, non-repulsive odor. This result shows field efficacy.
CLUMPABILl~Y TEST: At the time of collection, clumps from both Sample
A and Sample B were cohesive and non-friable when collPctPd daily. The aged clumps
were different. Clumps from Sample A were cohesive and non-friable; clumps from
25 Sample B were slightly less cohesive and slightly more friable. This result shows that
a reaction occurred, in-luced by the bent-fici~l c~ lres
AMMONIA TEST: The more aged specimens from Samples A and B were
evaluated for ammonia content. Clumps weighing 30 grams were placed in petri dishes
and 30 ml of hydrogen peroxide solution was added to each. The peroxide solutions
30 from Sample A litter frothed vigorously. The peroxide solutions from sample B litters
did not froth. This suggests that ammonia was present in Sample A clumps but not in
Sample B. Either the urea in Sample B was fixed and did not form ammonia, or, if
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ammonia was formed, it was utilized by the benPfici~l cultures. This test was
confirmed by using pure ammonia and pure urea. The ammonia samples frothed in the
presence of peroxide, while the urea sample did not, in~ic~ting that it was the ammonia
in Sample A that caused frothing.
S NON-CLUMPING LITTER TEST: A one week test was run, with and without
the bemP.fici~l org~ni.sm.c, on a commercially available non-clllmping litter to ~e~,. .,.;.,P
the efficacy of the treatmpnt in .cit~l~tion.c where urine could run through the litter and
pool at the bottom of the litter box. Sample C was untreated and Sample D cont~inP.~
1% by weight of a culture ~r~alaLion of b~llericial org~ni.cm.c. After three cats had
used the .c~mplP.s for one week, urine odor from Sample C was notably stronger than
that from Sample D. This result indicates that the beneficial org~nicmc are useful with
non-clumping litters.
CONCENTRATION TEST: Sample E was prepared by mixing ten pounds of
sodium be..ln,~ litter with five pounds of Sample B, producing a 0.33% concentration
of a culture plepa~alion of beneficial org~ni.cmc The odor of Sample E was
subst~nti~lly reduced as co.l,paled to the odor of Sample A.
AGING TEST: The ammonia test was performed on both fresh and aged,
treated litter.
a. Fresh: Very fresh urine clumps -- less than 8 hours old -- were taken
from three different litter boxes. Sample A, Sample B, and Sample E.
The ammonia test was performed. No foaming was observed in any
s~mple, in~lic~ting that urea had not yet converted to ammonia.
b. Aged: An ammonia test was run on a one week old clump from the
Sample E litter box. The sample bubbled vigorously in(lic~ting that urea
had converted to ~mmoni~ This result demonstrates that urea fixation
is stable for less than one week. Eventual breakdown is valuable in
converting wastes to usable fertilizer.
CONTROL TEST:
a. Ben~.fici~l Or~nicm.c: The ammonia test was run on 100% culture
plep~lion of bçnefici~l organicms. Only an occasional bubble was
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-16-
observed, indic~ting that the culture preparation alone does not interfere
with the foaming/nonfoaming test results.
b. Urine: The ammonia test was run on a fresh sample of human urine.
No foaming resulted. This in~ic~tes that nitrogen is present as urea and
later changed to ammonia.
FECAL MATTER TEST: The ammonia test was run on fresh, less that 8 hours
old fecal matter from Sample A and Sample B litter bo~es. Sample A foamed
vigorously with a brown foam. Sample B had a few tiny bubbles and no fo~ming
This in~icat~s that the ben~fici~l or~ni.cms are lc~ding the form~tion of odor c~ucing
nitrogenous compounds in cat feces, helping with odor control.
It is generally known that the primary odor causing component in cat urine is
ammonia, formed by the breakdown of the urea in fresh cat urine. The odor in catfeces is from skatole and indole. In order to track the formation, growth, and
disappearance of these and other compounds, cat urine and feces from Sample A and
Sample B, as well as the culture, itself, and both the treated and untreated sodium
benlo~ , itself, were tested with sensitive instruments. It was found that skatole and
indole were not detect~ble by the instruments at the levels found in litter boxes.
A~)pa~ ly, the concent~tion of these compounds was too low for analytical detection.
Thus, no q~ntit~tive tests could be conducted on these compounds. Inst~lment~l
analysis is useful within concentration limits measured in parts per million. However,
the human nose appears able to detect certain odors in concentrations of parts per
billion. Qualitative tests, using the human nose, showed that litter treated with
beneficial org~nicmc was effective in red~lcing odors of skatole and indole.
EXAMPLE 3
The following s~mr~les were ev~ te~
Sample A -- untreated Na Bçntonite litter.
"A" Urine -- from untr~aled Sample A one day old.
"B" Urine -- from treated Sample B one day old.
The determin~tion of ammonia by Potentiometric, Ion Selective Electrode was
performed according to EPA Method 350.3-1974. Appro~ ately 25 grarns of the
sample was broken up and placed onto a fritted glass funnel. The sample was placed
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in a closed system and purged with nitrogen at fifty milliliters per minute for twenty
mim~tes. The gas was purged through 110 ml of slightly acidic deionized water which
was then tested for ammonia with EPA Method 350.3
TABLE 3 -- QUANTITATIVE TEST FOR AMMONIA
SAMPLE ID CONCENTRATION OF AMMONIA
Sample A -- litter only 0.017 mg/L
"B" Urine - treated 0.026 mg/L
10"A" Urine- untreated 0.087 mg/L
Reliable detection limit for this method is 0.05 mg/L.
The EPA Method 350.3 analysis in(li~ted a dirre,c;.lce in the ammonia
concentration observed in the .c~mplPc Measurements of ammonia level in the blank
litter and in the urine from the treated litter were below the reliable detection limit of
the instrument, which could introduce inaccuracy in the reported levels of ammonia.
Nevertheless, the results inriit ~tPd a ~ ;ve difference. The untreated urine showed
an increasing ammonia concPnt~tinn in a 25 gram sample.
EXAMPLE 4
Blank specimens of both Sample A, untreated blank litter, and Sample B, treated
blank litter, were evaluated as controls. To determine qn~Lil~l;ve performance of the
culture, progressively aged urine ~mplP.s from both batches of litter were evaluated on
a day-to-day aging basis over an elapsed period of t~-vo weeks. The freshest samples
were less than 8 hours old, having been taken on the day of the test. Further s~mples
were aged each day from two to six days. Two samples from each group were allowed
to age eight more days and were tested when they reached 12 and 14 days aging.
The d~le. ",;"~tion of ammonia by PotentiomP.tric, Ion Selective Electrode was
performed according to EPA Method 350.3-1974. Approxim~tely 40 grams of the
sample was broken up and placed onto a fritted glass funnel. The sample was placed
in a closed system and purged with nitrogen at fifty millilitP.r.~ per minute for twenty
mimltes The gas was purged through 50 ml of slight acidic Nano-pure water which
was then tested for ammonia with EPA Method 350.3.
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TABLE 4 -- QUANTlIATIVE TEST FOR AMMONIA
SAMPLE B NH3 ,ug/g SAMPLE A NH3 I~g/g
TREATED UNTREATED
Control 0.01 Control 0.02
Day 1 0.36 Day 1 3.61
10 Day 2 0.26 Day 2 4.77
Day 3 11.6 Day 3 1.83
Day 4 4.77 Day 4 136.0
Day 5 186.0 Day 5 641.0
Day 6 7.23 Day 6 1,777
15Day 12 1,890 Day 12 2,847
Day 14 2,320 Day 14 2,435
The data for the first six days was placed on a graph and a line of best fit wasdrawn for both treated and u~ ca~ed s~mrlP.~s. The graph shows a difference in the
20 a-m-monia concentration observed in the samples. The treated samples showed a lower
ammonia concentration as compared to the untreated s~mples from day to day. The
ammonia concentration shows an increase from day to day in both treated and untreated
samples.
The data for days 12 and 14 are not graphed. The lower result for the ammonia
25 content of the untreated sample aged 14 days as opposed to the untreated sample aged
12 days may be due to depletion of the urea.
These results derived from the graph show that the urease negative org~nicm~
delay the form~tion of ammonia at the level of human olfactory detection, which is
about 20 ppm or 20 ,ug/g, by about two ad-1ition~l days. In an untreated litter box, this
30 threshold level is reached in two to three days. In the treated litter box, the threshold
level is not reached until almost five days.
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EXAMPLE 5
It is desirable to detP minP the effective concentrations of the culture. The
culture is more costly than typical litter such as bçntonitP. Therefore, the cost of adding
the culture to ull~eaL~d litter might inflllence the price of litter in a subst~nti~l f~hion
S Since cat litter generally is an ine~pellsi~,re, disposable commodity, it would be desir~bkP
know the minimllm useful level of the culture.
Six litter boxes were prepared with ten pounds of granular be.ntonite and culture
pl~dtion. The culture prep~tion was pulverized in a blender and further crushed
with a mortar and pestle. A postage scale was used to weigh the culture p,ep~dlion;
for smaller dos~gPs, estim~tPs were done by volume. For example, 0.1~o was 1/lOth
the volume of 1%. One box was used as a control (0% culture preparation). The other
boxes were dosed with: 2%, 1%, 0.50%, 0.25%, and 0.10% dried culture p,~dlion.
Four cats had free access to the six litter boxes; not all boxes were used each day.
Urine sample clumps were scooped daily and placed in labelled, unsealed plastic bags.
The llnce~lP,~ bags were placed in a five gallon bucket. So ~at each bag was exposed
to air, the bucket lid was left ajar. The control samples were kept in a bucket separate
from the treated s~mphP.s to avoid cross co~ ."il~tion of ammonia.
The s~mples were subjected to the Ammonia Test of Example 1. Bubbling of
the peroxide/urine clump sample indic~tes the presence of ammonia. No bubbling
in~icat~P.d the absPn~e of ammonia. A few tiny bubbles in~iicatPd a small amount of
ammonia. Many bubbles and swelling of the sample with air bubbles indicated a
cignific~nt amount of ammonia. The results of the Ammonia Test are reported in Table
5 with the following symbols:
+ = foamed
- = no foam.
The Odor Test of Example l was cond~lct~Pd by snifflng the sample clumps. The
results are reported in Table S with odor rated as follows:
- = could not perceive ammonia
+ = slight ammonia odor
++ = moderate ammonia odor
+++ = strong ammonia odor
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WO 96/11570 PCT/US95/13004
-20-
~ ~ , , , +
~ cq
O ~E~ + +
;~
+ + +
g3
¢ o Cq ~
o
O
E~ + +
o
c ~ E~ + + + +
,~ O ~ , m
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The culture treated s~mplçs had a mild, yeasty odor. The fragrance of the culture itself
could be detect~(l in the s~mples having the higher dosages. The data shows the culture
p~ on to be effective in l~dillg form~tion of ammonia down to 0.1%, which was
the lowest level tested. After five days, all s~mples treated with the culture pl~a aLion
had no ammonia odor. The peroxide test for ammonia, when applied to the treated
s~mples, showed no response on days one and two and a slight response or no response
on days 3 to 5.
It is believed that a smectite clay mineral with sodium as the domin~nt cation
associated with the e~ch~nge sites of the ~m~P~tite~ is especially suited to serve as a
buffer means for pH control in a clumpable pet litter. Sodium montmorillonite, also
known as sodium bçl~lQ~ e or Wyoming bentonite, is a readily available and widely
accepted Px~mple of such a smectite clay. Other suitable buffer systems might employ
ures of salts and acids of carbonate, phosphate or borate anions. When liquid isimbibed by the pet litter to form a clump, the sodium smectite or other buffer means
additives will create a pH greater than 7 and appro~ tely pH of 9 for OptilllUlll effect.
A solution that contains a weak acid or base plus the salt of that acid or base
is known as a buffer. Buffer mixtures regulate the pH of an aqueous solution so that,
when acid or base is added to the system, there is only a small change in the pH of the
system.
In the combin~tion of clllmping pet litter and dried urease negative bacterial
enzyme culture additive, the sodium bentonitP provides a desirable buffer property to
pet litter in ~ddition to its clllmping propelLy when exposed to acidic pet urine. The
burre~ g effect of sodium smectite clays or inorganic carbonate, phosphate and borate
buffer additives m~int~in.c a neutral or basic pH in the urine clump. The basic pH of
the urine clump provides the appropriate conditions to favor growth of the urease
negative bacterial enzyme culture additive and to inhibit the growth of urease positive
bacteria from the enviro~ ,ent.
EXAMPLE 6
In order to determine buffering action of pet litter, three pet litter m~teri~l~ were
evaluated for pH over seven days of use by three cats. The first product was pure
sodium bPntonitP. The second was commercially available Scoop Away litter, a product
CA 02203009 1997-04-17
W O96/11570 PCTAUS95/13004
of A&M Products. The composition of Scoop Away is about 50% sodium b~ntonite
and 50% other clays and chemical additives. The third was commercially availableFresh Step litter, a product of Clorox Corporation. Fresh Step is known to contain
attapulgite clay and may contain fuller's earth, as well. Each of these three m~teri~l~
5 was tested in both untreated and treated versions. The treated m~teri~l~ contained 0.5%
by weight of the culture plcp~lion. The six s~mples were tested for pH both whenthe s~mples were gathered and after the gathered samples were aged over a time period
ranging from æro days to six ~tldition~l days. The pH of a control sample of each
m~teri~l, which was not used by the cats, was measured initially to detP.rmine a base
10 reading and was evaluated again after six days aging.
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TABLE 6 -- pH OF PET Lll l~K OVER SEVEN DAY PERIOD
Treated Treated Treated
Sample Day Sodium Sodium Scoop Scoop Fresh Fresh
BentonitP Be.~lon;~ Away Away Step Step
Control- 9 9 7.5 7 8.5 8.5
fresh
Control- 9 9 7.5 7 8.5 8.5
6 days
Day 0 - fresh 8 8.5 7.5 8.5 8.5 8.5
Day 0 - aged 8 8.5 7.5 8 8.5 8.5
Day 1 - fresh 8 8.5 7 7.5 9 8.5
Day 1 - aged 7.5 8.5 7 8 8 8.5
Day 2 - fresh 8 8.5 8 9 8.5Day 2 - aged 8 8.5 8.5 8 8.5
15 Day 3 - fresh 9 7 7.5 8
Day 3 - aged 8 7 7 8
- Day 4 - fresh 8.5 7 7.5
Day 4 - aged 8.5 7 7
Day 5 - fresh 8.5 8.5 8
Day 5 - aged 8 7.5 8
Day 6 - fresh 8
Day 6 - aged 8
On days showing a blank, the particular sample was not used.
The test results show that sodium bentonite was the most ~lk~lin~ control
m~ti~.ri~l, with pH 9. Fresh exposure to cat urine caused a drop in the pH of untreated
sodium bentonit~ to either pH 8 or pH 8.5. With age, dhe s~mples showed very little
change. In two cases the sample pH dropped slighdy. Buffering appeared to be
effective and the pH st~bili7Pd in the range from 7-9. The treated sample of sodium
bentonite showed relatively less pH drop and r~m~in~d relatively more stable, indic~ting
a better buffering action.
- - -
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Untreated Scoop Away had a lower control pH of 7.5. Fresh exposure to cat
urine caused mixed results, with some samples showing a pH drop and another showing
a rise. Sample aging had substantially no effect on pH, except that the sample with
initial higher pH rose a bit with age. Treated Scoop Away started with a still lower
5 control pH of 7. It showed both increases and decreases in pH with both fresh and
aged exposure to cat urine. Bnffenng appeared to be effective and pH remained in the
range from 7-9 in all samples.
Both treated and untreated control s~mplPs of Fresh Step had an inte.rmediate
control pH of 8.5. With fresh exposure to cat urine, both s~mrles of Fresh Step had
10 a stable pH that changed only slightly, if at all, from the control value. All s~mplP.s of
all three pet litters m~int~inPd pH in the range from 7-9 throughout the tests, which
est~hli~hed that the buLr~ g action of the smçctite clay is sufficient to m~int~in the pet
litter in the desired pH range at least through the errecliv~ period of the culture.
The preÇe,t;nlial growth of urease negative bacteria inhibits the bacterial
15 conversion of urea to ~mmoni~ by urease positive bacteria from the environme.nt
Ammonia is the major odor component of the urine clump. If the pH of the urine
clump becomes acidic, urease positive bacteria can grow and will generate ammonia
from urea with a consequent odor. The buffer and urease negative bacteria culture
st~bili7es the urea for apploxi~ tely three extra days, to a total of about five days, until
20 urease positive bacteri~ eventually invade the urine clump and begin generation of
ammonia and odor.
EXAMPLE 7
An improved culture and p,~aldlion me~od were devised in order to increase
the finPnPcs of the culture preparation and to elimin~te grin~ing of the culture25 preparation. According to the procedures of FY~mplP. 1, thè urease negative cultures
were grown in liquid me(li~lm, reconctit~tPd from dry form at 12.0% solids level and
heat treated at 180F by holding for 45 minutPs Then the medi~lm was cooled to 90F
and was incubated with previously t~n~ferred urease negative cultures. The medium
was incub~tpd until pH dropped to 5.2. At this stage, it was neutralized to pH 7.0 and
30 the culture was allowed to incubate further. The neutralization steps were continued
until pH no longer dropped, indicating the depletion of nl~trient.C. At this stage 10
CA 02203009 1997-04-17
WO ~6/11570 PCT/US95/13004
pounds of sterile mixed 25% dextrose and 10% autoly_ed yeast extract solution was
added for every 1000 pounds of liquid me~ m, and the incubation was further
continued until pH dropped towards 5Ø This last step was introduced to furtherenh~nce cell growth. Then, the culture was cooled to 60F and neutrali7Pd to pH 7.0
S using a 50% solution of sodium hydroAide.
The culture thus prepared was added to granular silica at the ~l~rellcd rate of
25% weight~weight, with a range from 10 to 50%. The culture, added to silica, was
dried at ambient lel)lpG~ c;. After the culture was dried, powdered carbonate salts,
for example sodium bicarbonate, were added to the dried silica and culture at the
p~Grelled rate of 20% by weight, with a range from 10 to 40%. The culture plus
carbonate mix was uniformly bl~nded and was used to inoculate bentonite at the rate
of 0.1 to 0.25% by weight, for use as animal litter.
The improved culture plep~Lion of this e~c~mple, prepared according to this
new method, does not require ~rin(ling and worked çfficiçtltly. The following table
15 evaluates the perforrn~nce of this il~proved culture pl~Lion in comp~ri~on to the
original culture p~cpa,~lion of F~mplP 1. The improved culture preparation is referred
to in the table as "new culture preparation."
Tests were run using Dr. Elsey's brand scoopable litter, a 6 x 20 mesh sodium
bentonitf from Black Hills Bçntonite Dosage was 0.2 percent or one level tablespoon
20 (0.6 ounces) in 18 pounds of litter. After seven days, both the control and the original
forrn~ tion had a strong ammonia odor and foamed vigorously in the qualitative
ammonia test of FY~mple 2. The improved culture had a mild, yeasty smell and no
foam.
CA 02203009 1997-04-17
W O 96tll570 PC~rtUS95tl3004
Z o ,o
~
~E~
V~
O ~ ~ ' ' + + +
O ~ ~
¢ ~ ~
o
O ¢
~Ye ~ ,S~aS
O ~ C ~ ~I
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-27-
The foregoing is considered as illllctrative only of the principles of the
invention. Fur~er, since llwllel~us modifications and ch~nges will readily occur to
those skilled in the art, it is not desired to limit the invention to the exact formulation
S and operation ~escrihe~i and accordingly all s~it~hle mo-lific~tions and equivalents may
be regarded as falling within the scope of the invention as defined by the claims that
follow.
