WO2012135567A1 - Artificial feces - Google Patents

Artificial feces Download PDF


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WO2012135567A1 PCT/US2012/031348 US2012031348W WO2012135567A1 WO 2012135567 A1 WO2012135567 A1 WO 2012135567A1 US 2012031348 W US2012031348 W US 2012031348W WO 2012135567 A1 WO2012135567 A1 WO 2012135567A1
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French (fr)
Wendy Qin
Randall Glenn Marsh
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The Procter & Gamble Company
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Priority to US201161470219P priority Critical
Priority to US61/470,219 priority
Priority to US13/421,925 priority
Priority to US13/421,925 priority patent/US20120252042A1/en
Application filed by The Procter & Gamble Company filed Critical The Procter & Gamble Company
Publication of WO2012135567A1 publication Critical patent/WO2012135567A1/en



    • C12Q1/00Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/02Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving viable microorganisms
    • C12Q1/22Testing for sterility conditions


A composition to simulate feces. A method of using artificial feces to evaluate the efficacy of a cleaning product and/or cleaning procedure. A method of demonstrating the cleaning efficiency of a cleaning product and/or cleaning procedure using artificial feces.




This disclosure relates generally to compositions suitable for use as artificial feces.


Sometimes it is desirable to understand the chemical and/or physical behavior of feces. For example, it may be desirable to investigate how to remove feces from clothing or carpeting, as when toilet training a child or house breaking a puppy. It may be desirable to experiment with different methods or products for removing feces from hard surfaces, such as toilets or floors. It may also be desirable to evaluate how feces is handled by an absorbent article, such as a diaper, or removed from the skin, as with a personal cleansing wipe or toilet paper.

Investigators engaged in such work would generally prefer not to use real feces in experiments. Real feces, whether human or animal, may be capable of transmitting disease. Further, the smell of some feces samples, cultural norms, and other factors may make handling feces repugnant even when it is handled in a manner which minimizes the risk of disease transmission.

Some artificial feces alternatives have been proposed, and even sold commercially. However, when these products are used experimentally, the results may be inconsistent with experiments run with real feces, qualitatively or quantitatively. The value of the work done with such formulas may be reduced, because it remains uncertain whether the results of the study using artificial feces will be applicable when using real feces. Further, as a biological product, real feces is not a consistent substance. However, most artificial feces formulas are targeted to a single "type" of feces, and still only mimic a handful of the aspects of that feces type.

There remains a need for artificial feces.


In some aspects, the present disclosure relates to a composition useful as artificial feces. In some aspects, the present disclosure relates to the use of an artificial feces to evaluate cleaning products or regimens. Additional aspects and various non-limiting embodiments are described in the Detailed Description of the Invention, below. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a plot of adhesive force (in grams) versus hardness (in grams) for exemplary artificial feces formulas of varying water content. DETAILED DESCRIPTION OF THE INVENTION

In some aspects, this disclosure relates to an artificial feces, which may also be referred to as synthetic feces or fecal simulant. In some aspects, this disclosure relates to a simulated soil with a quantifiable marker that can be non-invasively measured on a surface. The embodiments described below are referred to as artificial feces, however, it should be understood that the formulas may be adapted to simulate other soils, such as food wastes, vomitus, humus, and the like. The artificial feces may have solid components, which may include dried vegetable(s), fiber, yeast, yeast derivatives, and/or fatty acids. The artificial feces may have liquid components, which may include water, a preservative, and/or a mucus material. The artificial feces may be useful, for example, in studying waste handling or removal, including cleaning and stain removal, without the malodor or risk of disease transmission associated with handling real feces.

In some embodiments, an artificial feces comprises dried vegetables. Suitable vegetables include, but are not limited to, tomato, spinach, cabbage, okra, white (button) mushroom, carrot, pumpkin, and combinations thereof. The vegetable, or the predominant vegetable, if multiple vegetables are used, may be selected based on the intended use of the artificial feces. For example, the vegetables may fluoresce at different wavelengths of visible light with different intensities. For example, white mushroom, carrot, tomato, pumpkin, spinach, and cabbage powders are all visible as red fluorescence under green light. However, white mushroom, cabbage, carrot, and pumpkin may have more intense (and therefore more easily visible) fluoresce than tomato and spinach. In contrast, tomato, cabbage, and spinach provide bright green fluorescence under red light, and carrot provides a bright blue fluorescence under blue light. Under black light, white mushroom, tomato, carrot, cabbage, and pumpkin powders are easily visible, but spinach is harder to see with the unaided eye. Thus, the vegetable or the proportions of various vegetables in the artificial feces may be selected such that the artificial feces can be viewed under a specific lighting condition. The total vegetable content of the artificial feces may be from about 15% to about 35% of the solid content of the artificial feces.

The vegetable or predominant vegetable may also be selected for relative content of Adenosine Triphosphate (ATP). ATP is a compound ubiquitous in living things, however, not all living things produce like quantities of ATP. The following processed food products are listed in decreasing order of typical ATP content: Tomato, peaches, sweet peas, beef, spinach powder, ham, cabbage, pumpkin, and carrot. If the artificial feces comprises ATP, it may be possible to track residues on a test surface using ATP quantification. For example, the artificial feces may be tested in advance for ATP content, in a known quantity of artificial feces applied to a test surface. The surface may then be cleaned or rinsed, and the surface tested for ATP. The quantity of ATP on the surface may be directly attributed to the artificial feces, for example, if the test surface is an inanimate object. Relative amounts of ATP may be used to infer the amount of artificial feces on animate surfaces, such as living skin.

In some embodiments, the artificial feces comprises a source of fiber. Exemplary sources of fiber include, but are not limited to, psyllium husks, processed foods, a-cellulose, cellulose derivatives including methyl-cellulose, corn starch, and combinations thereof. If processed foods are used, the food product may be selected for high fiber content. The food product may be, for example, ground, boiled, diced, shredded, lyophilized, sieved, suspended (as in a liquid) or combinations thereof. If a processed food is used, alone or in combination with other materials, as the fiber source, the food may be selected for high fiber content, such as greater than 0.5 grams of fiber per tablespoon, or greater than 1.0 grams of fiber per ounce. Exemplary foods which may have a relatively high fiber content include raspberries, pears (including the skin), apples (including the skin), strawberries, bananas, oranges, dried figs, raisins, whole wheat pasta, pearled barley, bran flakes, oat bran, oatmeal, popcorn (popped), brown rice, rye bread, whole wheat bread, multigrain bread, sweet peas, lentils, black beans, lima beans, sunflower seed kernels (i.e., shelled sunflower seeds), almonds, pistachio nuts (i.e., shelled pistachios), pecans (i.e, shelled pecans), artichokes, broccoli, turnip greens, sweet corn, Brussels sprouts, potatoes (including the skin), tomato paste, raw carrots, or combinations thereof. The fiber may provide bulk and water retention to the artificial feces. Less fiber may give an artificial feces with less cohesion than an artificial feces with relatively more fiber. To simulate soft, somewhat runny infant feces, the fiber may make up about 0.25% to about 1% of the solid content of the artificial feces. For other feces, the fiber may comprise up to 30% of the solid content of the artificial feces.

In some embodiments, the artificial feces may comprise yeast and/or yeast derivatives, such as hydrolyzed yeast autolysates. The yeast, if present, may be an additional source of ATP and contribute bulk to the artificial feces. Yeast products (whole cells and cell walls) may also provide proteins, polysaccharides, and other compounds which represent components of microbial origin in feces. Without wishing to be bound by theory, these elements may influence the surface chemistry, surface energy, and/or rheology of the artificial feces, and may, therefore, contribute to realistic "behavior" or characteristics. The yeast, if present, may be about 30% to about 50% of the solid content of the artificial feces. The yeast derivative, if present, may be about 10% to about 20% of the solid content of the artificial feces. Food grade yeast products may be used to represent proteins and microbial particles common in human feces. Live or inactivated yeast may be used, however, inactive yeast may produce a more stable intermediate product (i.e., during preparation), since the inactive yeast will not have on-going metabolic processes that might change ATP or protein content during processing.

In some embodiments, the artificial feces comprises a fatty acid and/or fatty acid soaps. If the artificial feces is used to simulate real feces, fatty acids typically found in the feces of the animal being studied may be used. The fatty acid may comprise palmitic acid, calcium-stearate, lauric acid, myristic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and combinations thereof. Sources of fatty acids may be used, including, but not limited to, cooking (vegetable) oil, Coffee Mate™ coffee creamer products, cream cheese, butter, peanut butter, ground sesame seed powder, and combinations thereof. If present, the fatty acid and/or fatty acid soap may be about 2% to about 50%, or about 15% to about 25% of the solid content of the artificial feces. The inclusion of one or more short chain fatty acids, having an aliphatic tail of less than six carbon atoms, may be used to enhance the realism of the artificial feces, as short chain fatty acids are a contributor to the odors associated with real feces. Realistic odor may be helpful in simulating human interactions with real feces. For example, an aversion to contacting real feces may change the way a person engages in a cleaning task. A real smell and/or appearance may help minimize study artifacts arising from researchers' and/or participants' awareness that the artificial feces is not real. Of course, other odorous compounds, or mixtures of fatty acids and/or other odorous compounds, can also be used, including, but not limited to, sulfur-containing compounds (such as hydrogen sulfide), nitrogen-containing compounds (such as amines), and certain aldehydes, ketones, alcohols, or any other compound having an unpleasant odor.

On the other hand, the artificial feces may seem quite realistic, and researchers or participants in a study may show some reluctance to handling the artificial feces. Social norms regarding the handling of feces are very strong, and even when the formula is intellectually recognized as artificial feces, it may still be unpleasant or "gross" to handle the artificial feces. In some embodiments, pigments may be added to make the artificial feces look like real feces. It is to be appreciated that pigments that are responsible for the color of real feces may be added to the artificial feces. For example, stercobilin, a pigment found in real feces, may be used. In some embodiments, dyes may be added to make the artificial feces look less like real feces. For example, non-limiting dyes which might be used in an artificial feces composition include food grade dyes, fluorescent dyes, water tracers (EPA-approved fluorescent dyes), colored or fluorescent beads (such as those commercially available as Glo-germ™ from DMA International, or Molecular Probes™ from Invitrogen), fluorescent tagged proteins, fluorescent tagged microbial particles, colored fruits and vegetables (such as beets, blueberries, or ground parsley flakes), similar colored or fluorescent materials, and combinations thereof. Instead of, or in addition to, dyes, fragrances might be used in an artificial feces composition. Like dyes, fragrances may signal that the composition is not real feces. Non- limiting fragrances which might be used in an artificial feces composition include essential oils (botanically-derived or synthetic), industrial perfumes or odor products, vegetable smells (synthetic or natural, including asparagus, bacon, peanuts, cheese, or combinations of these). In addition, the vegetable matter may be modified to include pleasant-smelling components, such as dried rosemary, dried sage, other dried herbs, dried flowers, or combinations thereof. Some people, however, may find pleasantly-scented artificial feces disconcerting, particularly if the artificial feces composition still looks very similar to real feces.

The solids may be ground into small particles. For example, the vegetable matter, fiber, and/or the yeast may be ground and sieved such that the nominal particle size is between about 100 and 500 microns, or between about 200 and 400 microns, or between about 250-300 microns. The vegetable, fiber, and/or yeast components may be sieved such that only particles which pass through a 300 micron sieve are used. If the solids are purchased as powders, it may be unnecessary to grind them, but may still be desirable to sieve them. Sieving the powders may contribute to more consistency across different batches of artificial feces. Smaller particles may make for a smoother composition, which may be suitable for mimicking, for example, the feces of a human infant. Larger particles or even small dices of dried vegetables may be used to simulate the feces of older animals, such as children or adults. Of course, a mix of particle sizes and morphologies, up to and including small cubes or chunks, could be used. If powdered or pre-ground products are purchased, attention should be paid to any additives. Anticaking agents, such as Si02, may vary between products or between lots or batches of the same product, and can cause variation in the artificial feces. The content and/or consistency of the vegetable additives may be easier to control by purchasing dried vegetables whole, or in pieces or large dices, and grinding the vegetables just prior to use. The artificial feces may comprise a liquid component. The liquid component may be predominantly water. If surface interactions and/or surface energy are of interest, deionized water may be used. Surfactants or other additives may also be used to vary the surface tension and/or surface energy of the artificial feces. The liquid component may comprise one or more preservatives, to reduce microbial growth in the artificial feces and enable a longer usage-life. Citric acid, which naturally arises in most animal feces both from food sources and as a by-product of the Krebs cycle, may be added to the water. Other acids, such as, phosphoric acid, acetic acid (vinegar), ascorbic acid, malic acid, oxalic acid, salicylic acid, organic acids, and combinations thereof may be used instead of or in addition to citric acid. It may be desirable to use one or more acids naturally present in foods, including fruits, vegetables, and drinks, such as soda and sports drinks. Fruit juices, soda, and vegetable drinks may also be used as acid sources. It may be desirable to adjust the pH until the artificial feces is inhospitable to many micro-organisms; a pH of less than 5, or approximately 4.6, has been found useful for this purpose. An acid, if used, may be present at a Molarity (moles/Liter) between 5xl0~3 and 9xl0~3. Of course, depending upon the formula, including any basic (alkaline) ingredients, the pKa of the acid being used, and the desired pH of the artificial feces, the desired Molarity of the acid or acids may vary within or outside this exemplary range. The liquid component may comprise benzyl alcohol. Benzyl alcohol is a naturally occurring substance in many plants, and may help inhibit microbial growth in the artificial feces between the time it is prepared and the time it is used. The artificial feces may comprise sodium benzoate. Sodium benzoate also occurs at low levels in dietary plants, and may help inhibit microbial growth in the artificial feces. In addition to, or instead of, benzyl alcohol and/or sodium benzoate, potassium sorbate, sorbic acid, or combinations thereof may be used. The primary purpose of the citric acid, benzyl alcohol, and/or sodium benzoate is to reduce microbial growth in the artificial feces; other preservatives or anti-microbials could be substituted for these compounds. Citric acid, benzyl alcohol, and/or sodium benzoate provide a preservative mixture which may be useful, for example, when the artificial feces may come in contact with human skin, because the compounds are naturally occurring, non-toxic, and at suitable concentrations, generally non-irritating. Substitute preservatives may be selected for similar properties, if desired. One or more acids may be desirable as a preservative or as a component of a preservative system because acids may lower the pH of the artificial feces, which both inhibits some microbial growth and helps preserve ATP in the triphosphate structure (i.e., maintain ATP counts over time). The liquid component may comprise a mucus material, such as glycerol, egg white (fresh or dried), glycoproteins, polyacrylamides, polyvinylpyrrolidones, cellulose derivatives including methyl-cellulose and ethyl-cellulose, natural gums including gellan gum, polysaccharides, plants or plant exacts including okra, animal mucin including pig stomach mucin, combinations thereof, or other materials with similar adhesive and rheological properties. The mucus material, if present, may comprise between about 1% and about 20% of the liquid component of the artificial feces, by weight.

Although the artificial feces has been described as having solid and liquid components, it should be appreciated that these are not critical distinctions. As described in the examples herein, it may be convenient to relate proportions of components of the artificial feces to other elements in a like form, comparing, for example, grams of solids to grams of solids. However, many of the constituents described herein are available in multiple forms, including, for some compounds, solids, gels, liquids, suspensions, and the like, and the description should not be understood to limit the use of a particular compound to a particular form. It should be appreciated that proportions of compounds may be adjusted if the form used is changed (i.e., percent of solids vs. molarity of a liquid component, or to take into account the added liquid if using a suspension or solution rather than a powder). Accordingly, the descriptions of solid components and liquid components is convenient for describing certain examples, and is not meant to limit the form of the elements or the process for making the artificial feces.

One problem with some commercially available fecal simulants is that they do not retain water in the same way as real feces. Many fecal simulants dry much faster than real feces. This can be challenging in an experimental setting, because even freshly prepared artificial feces may dry out if there is a delay, for example, between applying an artificial soil and performing a cleaning step, or if the artificial soil is not quite tightly capped for even short periods of storage. This can also be a challenge if gravimetric measurements are taken, as time-to-testing can become a predictive variable for some previously known artificial feces formulas. Various humectants may be used to adjust the drying rate of artificial feces to make it easier to handle and/or to better simulate real feces. For example, glycerin, salts (such as sodium chloride), or sugars (such as sucrose), or combinations of these, may be used to retain water in the artificial feces to simulate water holding properties and the rate of evaporative drying in room temperature and humidity air (i.e., approximately 72-75 °F and 40- 60% relative humidity, or the typical temperature and humidity in the laboratory or room where the artificial feces will be used). The artificial feces properties may be adapted by modifying the formula. ABM texture (hardness, adhesive force to standard control surface), can be modified by varying the water content of the artificial feces. In general, adding less water will make a harder artificial feces, and adding more water will make a runnier (lower hardness) artificial feces. For example, using the solid premix described below in Example 8, artificial feces described as dry can be prepared using a water content, for example, of 55 to 56% water, giving a composition with a hardness above about 325g. As a