CAUSTIC CLEANING COMPOSITIONS

Abstract

An aqueous caustic composition comprising: a caustic component; a surfactant; and an amino acid; wherein said composition has an advancing contact angle (θ.sub.A) of less than 80 degrees and a receding contact angle (θ.sub.R) of less than 20 degrees and processes associated therewith.

Claims

1. An aqueous caustic composition comprising: a caustic component; a surfactant; and an amino acid; wherein said composition has an advancing contact angle (θ.sub.A) of less than 80 degrees and a receding contact angle (θ.sub.R) of less than 20 degrees.

2. A composition according to claim 1 wherein said composition has a surface tension (SFT) when measured using a Wilhelmy plate with a tensiometer of less than 40 mN/m.

3. A composition according to claim 1 wherein said composition has a surface tension (SFT) when measured using a Wilhelmy plate with a tensiometer ranging between 25 and 35 mN/m.

4. A composition according to claim 1 wherein said caustic component is selected from the group consisting of: sodium hydroxide; potassium hydroxide; sodium metasilicate; and combinations thereof.

5. The composition according to claim 1 wherein said caustic component is sodium hydroxide.

6. The composition according to claim 1 wherein said amino acid is selected from the group consisting of basic amino acids.

7. The composition according to claim 1 wherein said amino acid is selected from the group consisting of: lysine; histidine; arginine; hydrates and salts thereof and combinations thereof.

8. The composition according to claim 1 wherein said amino acid is lysine Monohydrochloride Monohydrate.

9. The composition according to claim 1 wherein said the surfactant comprises a Guerbet alcohol.

10. The composition according to claim 1 wherein said surfactant comprises a Guerbet alcohol

11. The composition according to claim 1 wherein said surfactant is selected from the group consisting of: Plurafac® LF 431; Lutensol® XL80; Lutensol® XP80; and combinations thereof.

12. The composition according to claim 1 wherein said surfactant is Plurafac CS-10.

13. The composition according to claim 1 wherein said caustic component is present in a concentration ranging from 30-60 wt. % of the total weight of the composition.

14. The composition according to claim 1 wherein said caustic component is present at 60 wt % of the total weight of the composition.

15. The composition according to claim 1 wherein said surfactant component is present in a concentration ranging from 2 to 20 wt % of the total weight of the composition.

16. The composition according to claim 1 wherein said surfactant component is present in a concentration ranging from 2 to 10 wt % of the total weight of the composition.

17. The composition according to claim 1 wherein said amino acid is present in a concentration ranging from 1 to 15 wt % of the total weight of the composition.

18. The composition according to any claim 1 wherein said amino acid is present in a concentration ranging from 1 to 5 wt % of the total weight of the composition.

19. A process for removing a residue from a substrate, comprising the steps of: preparing a diluted cleaning solution, said diluted cleaning solution made by adding water to a concentrated cleaning solution so that the amount of caustic component contained in said diluted solution ranges from about 0.05% to about 5% by weight of said cleaning solution, said concentrated cleaning solution comprising: a caustic component; a surfactant; and an amino acid; and water wherein said composition has an advancing contact angle (θ.sub.A) of less than 80 degrees and a receding contact angle (θ.sub.R) of less than 20 degrees. applying said diluted cleaning solution to the substrate comprising the residue; allowing a sufficient period of exposure of the cleaning solution to the substrate; and removing said residue by rinsing with a fluid; optionally, the rinsing step is repeated.

20. The process according to claim 19 further comprising: an acid cleaning step following the rinsing step and second rinsing immediately after the acid cleaning step.

21. The process according to claim 19 wherein said substrate is a metallic surface.

22. An aqueous caustic composition comprising: a caustic component; a surfactant; and an amino acid selected from the group consisting of: Lysine; Arginine; Histidine; Aspartic Acid; Glutamic Acid; Serine; Asparagine; Glutamine; Tyrosine; Methionine; Alanine; Valine; Cysteine; Proline; and Glycine; wherein said composition is stable at temperatures of up to 45° C. for a period of up to 14 days.

23. The aqueous caustic composition according to claim 22 where said amino acid is lysine.

Description

DESCRIPTION OF PREFERRED EMBODIMENTS

[0057] It will be appreciated that numerous specific details have been provided for a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Furthermore, this description is not to be considered so that it may limit the scope of the embodiments described herein in any way, but rather as merely describing the implementation of the various embodiments described herein.

[0058] Preferably, the formulations include surfactant blends that enhance the surface wetting properties of the systems and assist in releasing any deposited materials. More preferably, the surfactant blend is stable at high pH levels and has very low foamability allowing an efficient application in CIP systems without any issues of pump cavitation or unwanted pressure build-up. According to a first aspect of the present invention, there is provided an aqueous caustic composition comprising: [0059] a caustic component; [0060] a surfactant; and [0061] an amino acid.

[0062] Caustic Compositions

[0063] According to a preferred embodiment of the present invention, caustic compositions for use in cleaning in place (CIP) of industrial equipment and piping of equipment used in the food industry, the beverage industry and in the dairy industry were developed using an anionic surfactant (Plurafac® CS-10) and an amino acid. More preferably, the amino acid was lysine. Even more preferably, the amino acid is L-Lysine monohydrochloride monohydrate.

[0064] Table 1 provides for the composition of various caustic formulations which were subsequently tested for a number of parameters including organic and inorganic scale dissolution. The performance of compositions comprising an amino acid, in most cases, L-Lysine monohydrochloride monohydrate and Plurafac® CS-10, was compared to compositions containing none of them or only a single one.

TABLE-US-00001 TABLE 1 Composition of the various caustic formulations Sample# EA74 EA75 EA77 EA78 EA80 EA81 EA82 NaOH 60.0 60.0 60.0 60.0 60.0 60.0 60.0 (50%) Plurafac 0.0 10.0 10.0 10.0 0.0 0.0 0.0 CS-10 (50%) L-Lysine 0.0 0.0 1.0 2.5 1.0 2.5 5.0 Monohydro chloride Monohydrate Water 40.0 30.0 29.0 27.5 39.0 37.5 35.0 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0

[0065] The caustic cleaning composition according to a preferred embodiment of the present invention is usually used as a concentrate to be diluted in an aqueous solution with water or hot water according to the above-mentioned various facilities and the contaminants present. The cleaning of tanks, piping, etc. in for example, beer factories, brewery factories, beverage factories such as juices and soft drinks, milk factories, frozen foods and other foods, various food manufacturing factories, and machine, sterilizer, heat treatment machine, and other equipment, machinery, and pipes, containers, craters, barrels, and other containers for mechanical automatic cleaning, especially CIP cleaning methods, is performed with said aqueous solution comprising 0.2 to 30 wt % of alkaline (caustic) content with respect to the total weight of the composition. According to a preferred embodiment, it is preferable to use an aqueous cleaning solution diluted so as to be in the above range.

[0066] Preparation of Dehydrated Organic

[0067] In order to simulate the inorganic and organic scale formed in a food & beverage processing plant, fruit juice products were used. The fruit juices used consisted of a fruit juice containing chunks of suspended fruits. It was used to simulate what is happening in a beverage plant.

[0068] Dehydrated Organic: One can of strawberry-banana fruit juice (240 mL) was decanted into a crystallization dish. The crystallization dish was then placed in the oven at 45° C. for 24 h. After 24 h, the dehydrated organic was taken out of the oven and placed in a sealed jar. The mass was around 40 g of a paste-like organics.

[0069] Dissolution Experiments

[0070] For the dissolution experiments, the caustic compositions were diluted to the respective concentration of NaOH indicated in each series of experiments. 25 mL of the diluted formulation was added to a 100 mL beaker with a magnetic stirring bar. 1 g of the dehydrated organics (strawberry banana) was added to the caustic formulation. The solutions were then mixed at ambient temperature (˜21° C.) for 1 h at 500 rpm. After 1 h, the solution was passed through a 100 mesh (150 microns) screen. The screen was weighed prior, wetted with the solution and was then dried at room temperature and reweighed, the difference in weight is the undissolved organics.

[0071] At the outset, it is acknowledged that there are practical limitations to the dissolution testing carried out using non-deposited pieces of organic material. While the dissolution results will indicate an effectiveness of the composition in the presence of floating material (organic materials present in the beaker) it does not take into account in situ scale present on industrial equipment. This shortcoming was overcome by performing surface tension measurements and dynamic contact angle measurements on each composition which would provide important information about the behavior of each tested composition if it were used on fouled (containing scale) industrial equipment.

[0072] Surface Tension Measurements

[0073] The surface tension (SFT) was measured using a Wilhelmy plate with a Kruss 100C force tensiometer.

[0074] Dynamic Contact Angle Measurements

[0075] Dynamic contact angle measurements were conducted using the Wilhelmy plate method with a Kruss 100C force tensiometer. A parafilm plate was used as a hydrophobic surface to measure the efficiency of the formulations in reducing the contact angles. The advancing and receding contact angles (θ.sub.A and θ.sub.R) were measured. They are indicative of how efficient the formulation can change the wettability of a hydrophobic surface to be more water-wet for easier cleaning of the surfaces. The advancing angles (θ.sub.A) is always higher than the receding contact angles (θ.sub.R) as the plate advances in the fluid dry. But while receding, the molecules were already oriented at the surface.

[0076] Dissolution Testing

[0077] Table 2 presents surface measurements for the dilutions to 2% NaOH (eq.). In absence of any additives, NaOH does not change the surface tension and contact angles from the values corresponding to pure water (The contact angle for Parafilm with water is 115/80). Adding L-Lysine monohydrochloride monohydrate to NaOH solutions gave similar results. When adding Plurafac® CS-10, both the surface tension and contact angles decreased significantly. This would allow the formulation to effectively penetrate the deposited organics on hard surfaces and enhance the dissolution process to render a clean and shiny surface.

[0078] Table 2 also presents the dissolution efficiency measurements for caustic formulations diluted to 2% NaOH (eq.).

TABLE-US-00002 TABLE 2 Surface measurements and dissolution efficiency measurements for caustic formulations EA74 to EA82 Sample# EA74.S EA75.S EA77.S EA78.S EA80.S EA81.S EA82.S pH 13.0 13.1 13.2 13.3 13.2 13.2 13.2 SFT 72.44 30.94 31.4 31.3 72.7 73.2 73.5 (mN/m) θ.sub.A(°) 114.3 61.31 60.7 61.3 115.2 115.6 115.3 θ.sub.R(°) 80.59 22.87 15.2 10.7 80.7 83.5 85.1 Original 1 1.03 1 1.02 1.0 1.0 1.1 Organics (g) Undissolved 0.1388 0.0514 0.0016 0.1251 0.1300 0.3975 0.5353 Organics (g) Organic 86.1 95.0 99.8 87.7 87.4 60.3 49.0 Dissolution (%)

[0079] According to a preferred embodiment of the present invention, the composition comprising Plurafac® CS-10 with L-Lysine monohydrochloride monohydrate showed highly desirable performance. The compositions containing only L-Lysine monohydrochloride monohydrate did not perform quite as well. This is also true for only caustic formulation or caustic compositions with only Plurafac® CS-10. As shown for compositions EA80 to EA82, dissolution decreases with increasing the concentration of Lysine in absence of Plurafac® CS-10. It was determined that approximately 1 wt % Lysine maximum would offer optimal dissolution in combination with Plurafac CS-10.

[0080] Subsequently, Composition EA77 was diluted to 2, 1, 0.6, 0.3, and 0.2% NaOH (eq.) to create formulations EA96; EA97; EA98; EA99; and EA100. Surface measurements for these dilutions are presented in Table 3. Both surface tension and dynamic contact angles increased slightly with dilutions. Table 3 also presents the dissolution efficiency measurements for caustic formulation EA77 diluted to 2, 1, 0.6, 0.3, and 0.2% NaOH (eq.). As the formulation is diluted, the overall concentration of the components is decreasing, however, the organic dissolution efficiency does not change.

TABLE-US-00003 TABLE 3 Surface measurements and dissolution efficiency measurements for caustic compositions diluted to 2, 1, 0.6, 0.3, and 0.2% NaOH (eq.) Sample # EA96 EA97 EA98 EA99 EA100 NaOH (%) 2.00 1.00 0.60 0.30 0.20 SFT (mN/m) 31.15 31.39 32.39 34.03 36.22 θ.sub.A (°) 59.97 60.35 61.94 68.43 71.7 θ.sub.R (°) 15.18 16.32 23.02 31.40 40.42 Original 1.01 1.06 1.04 1.07 1.01 Organics (g) Undissolved 0.08 0.03 0.03 0.0396 0.0276 Organics (g) Organic 92.13 97.61 96.81 96.30 97.27 Dissolution (%)

[0081] Subsequently, another series of compositions was prepared where the content of the surfactant was varied. The Plurafac® CS-10 surfactant loading was decreased to 5 and 2 wt % to make the formulation more commercially viable but without compromising the performance. Dissolution tests were conducted with those new formulation with a target dilution of 0.6 wt % of NaOH (eq.). Table 4 shows the composition of both the standard and optimum with low surfactant loading and their physical properties.

TABLE-US-00004 TABLE 4 Formulations of the standard composition and optimum composition with low surfactant loadingand their physical properties. Sample # EA136 EA137 EA138 EA139 NaOH (50%) 60.0 60 60.0 60 Plurafac CS-10 5.0 2 5.0 2 (50%) L-Lysine 0 0 1 1 Hydrochloride Monohydrate Water 35.0 38.0 34.0 37.0 Total 100.0 100 100 100 Physical Properties pH 14 14 14 14 Density 1.33197 1.33239 1.33332 1.33033 SG 1.33437 1.33 1.33572 1.33242

[0082] Table 5 shows that neither the surface tension nor dynamic contact angles significantly changed as the formulations diluted to 0.6 wt % NaOH (eq.).

TABLE-US-00005 TABLE 5 Surface tension and dynamic contact angles of the caustic formulations diluted to 0.6 wt % NaOH (eq.) EA136 EA137 EA138 EA139 SFT 31.1 31.6 31.1 31.7 (mN/m) θ.sub.A (°) 64.1 61.6 58.3 60.5 θ.sub.R (°) 5.0 13.6 11.2 13.6

[0083] Then the dissolution tests on the organics were conducted with dilution to 0.6% NaOH (eq.). Table 6 presents the dissolution efficiency and it shows that the efficiency of the compositions tested was clearly not affected by the dilution to 0.6% NaOH (eq.).

TABLE-US-00006 TABLE 6 Dissolution efficiency measurements for acidic formulations diluted to 0.6% NaOH (eq.) EA136 EA137 EA138 EA139 Original 1.04 1.00 1.06 1.00 Organics (g) Undissolved 0.06 0.06 0.05 0.05 Organics (g) Organics 94.20 93.91 95.10 94.96 Dissolution (%)

[0084] Finally, the corrosion tests with coupons of SS316 were conducted for the formulations in Table 6 diluted to 0.6% NaOH (eq.). The conditions for the corrosion tests were 60° C. and for 1 h. Corrosion tests were conducted on coupons of SS316 at 60° C. for 1 h and there was no change in weight of the coupons (0.0 lb/ft2).

[0085] Studying the Hydrotropic Effect of Amino Acids on Composition Stability of High-Alkaline CIP

[0086] The goal of this study was to study the hydrotropic effect of different amino acids on high-alkaline Clean-In-Place (CIP) formula stability, especially at high weather temperatures (up to 45° C.). Previously, lysine was studied to increase the solubility of Plurafac® CS-10 in 30 wt % NaOH. However, it did not perform optimally at high temperatures. Therefore, other amino acids were studied to investigate their potential hydrotropic effect on improving formula stability.

[0087] Compositions were prepared using 2 wt % of Plurafac CS-10®, 30 wt % of NaOH and various amino acids with variable loading from 0.5 to 4 wt %. The clarity, turbidity and phase separation for each sample were noted, evaluated and used as a measure to evaluate the composition stability over time at room temperature (˜20° C.) and 45° C.

[0088] Hydrotropic Effect of Amino Acids

Procedure

[0089] 1—Compositions were prepared by proper mixing of the chemicals following the order of addition as in Table 7. [0090] 2—50 g sample was prepared for each amino acid using glass jars. [0091] 3—Water was mixed with NaOH until the solutions became clear. [0092] 4—The corresponding amino acid (from 0.5% to 4% wt) was then added and stirred well until dissolved. Note: leucine, tryptophan and phenylalanine were not soluble. [0093] 5—Plurafac CS-10® (2% wt) was added to each sample with continuous stirring for at least 20-30 min. [0094] 6—Each sample was divided into two 20 mL vials (one kept at room temperature and the other stored in a water-bath at 45° C.). [0095] 7—Samples (CSR-CIP AA 1 to 80) were checked every day for clarity changes, turbidity, or phase separation.

TABLE-US-00007 TABLE 7 Chemicals used for formula preparation Order 0.5% 1% 2% 3% 4% of amino amino amino amino amino addition Material acid acid acid acid acid 1 Water 37.50 37.00 36.00 35.00 34.00 2 NaOH, 50% 60.0 60.0 60.0 60.0 60.0 3 Amino Acid 0.5 1.0 2.0 3.0 4.0 4 PlurafacCS-10 2.00 2.00 2.00 2.00 2.00 Total (g) 100 100 100 100 100

[0096] Results

[0097] Initial solubility testing showed that some amino acids with a long hydrophobic side chain (such as tryptophan, phenylalanine, and leucine) were insoluble into 30% NaOH solution. Therefore, these amino acids were excluded from further testing. All other amino acids produced clear solutions before the surfactant addition. However, upon the addition of Plurafac® CS-10, most samples became slightly turbid or turbid; only, methionine, proline, and valine produced very clear solutions.

[0098] Samples were checked over time for their clarity, turbidity, or any phase separation at room temperature and 45° C. While samples' turbidity/clarity at room temperature did not significantly change for all amino acids (see Table 9) up to the date of this report (˜2 weeks from the first sample was prepared). However, samples kept at 45° C. showed marked changes in their clarity after different periods (see Table 10), based on the amino acid added. All samples were compared to a sample prepared without any amino acid that remained slightly turbid, with no phase separation, over time at room temperature and 45° C.

[0099] 1. Effect of Amino Acids with Positively Charged Side Chains (Histidine, Lysine, and Arginine)

[0100] Samples prepared with histidine and arginine remained stable but slightly turbid at room temperature for at least 18 days without any observed separation. However, all samples, with different amino acid concentrations, underwent a phase separation after 2-3 days at 45° C. for both amino acids. Samples with 1% surfactant were also prepared using different loading of histidine and the results were similar to those obtained for 2% surfactant. Such samples (1% surfactant and histidine) were slightly turbid and stable at room temperature for more than 2 weeks with a phase separation occurring at 45° C. after 2-3 days.

[0101] In comparative testing, it was determined that lysine outperformed histidine and arginine with enhanced thermal stability at 45° C. Table #8 (below) shows that Lysine significantly improved the stability of Plurafac CS-10 in 30% NaOH at 45° C.

TABLE-US-00008 TABLE 8 Summary of the stability results at 45° C. for various compositions with and without lysine Plurafac Stability at Lysine (%) NaOH (%) CS-10 (%) 45° C. Sample 1 3 30 2.0 3-5 days Sample 2 3 30 1.5 21 days Sample 3 3 30 1.0 28 days Sample 4 0 30 0.5 8 days Sample 5 2 30 0.5 35 days

[0102] 2. Negatively Charged Amino Acids (Aspartic and Glutamic Acids)

[0103] Glutamic acid and aspartic acid produced slightly turbid solutions that remained stable without phase separation for more than 2 weeks at room temperature (date of this report). At 45° C., glutamic acid samples (with all amino acid loadings) remained stable, but slightly turbid, with a phase separation occurring after 5-7 days for all samples. In comparison, samples with aspartic acid (all concentrations) at 45° C. exhibited a phase separation after 3-5 days

[0104] 3. Amino Acids with Polar Uncharged Side Chains (Serine, Asparagine, Glutamine)

[0105] All these amino acids produced slightly turbid or turbid samples that remained stable at room temperature without any phase separation for 14 days (date of report). At 45° C., phase separation was clearly observed after 2-3 days for serine samples (all concentrations), 2 days for asparagine or glutamine (3 and 4%), and 6 days for samples with lower concentrations of asparagine or glutamine (1 and 2% wt).

[0106] 4. Amino Acids with Hydrophobic Side Chains (Alanine, Valine, Leucine, Methionine, Phenylalanine, Tryptophan, and Tyrosine)

[0107] Leucine, phenylalanine, and tryptophan were insoluble in 30 wt % NaOH solution. Methionine produced crystal clear samples that remained stable, with slight turbidity for some samples, at room temperature for up to 10 days without any separation (date of this report). However, such methionine-containing samples underwent a phase separation after 2-3 days at 45° C. Alanine, glycine, and tyrosine produced slightly turbid samples that were stable for 13 days without any phase separation. However, phase separation was observed for these samples after 1-3 days at 45° C., for all amino acid concentrations.

[0108] A photograph was taken for samples, prepared with tyrosine (0.5-4% loadings) and the sample was kept at room temperature for 10 days, as an example for turbid samples.

[0109] In contrast, valine produced crystal clear samples that remained stable at room temperature and 45° C. for up to 3-6 days. After 1 week, samples stored at room temperature with 2, 3 and 4% wt changed to slightly turbid, but without any phase separation. Samples with 0.5 and 1% are still clear for up to 2 weeks (date of report). At 45° C., samples with lower concentrations of valine (0.5 and 1% wt) underwent a phase separation after 1 week while samples with 2, 3 and 4% valine are still stable, but not clear, with the clearest sample that prepared with 2% wt valine. This result demonstrates that 2% valine is a critical concentration point for sample storage at room temperature and 45° C. Consequently, further experimentation for different valine loading (1.5, 2, 2.5% wt) was carried out.

[0110] Two photographs were taken to show the valine samples (0.5, 1, 2, 3 and 4%) respectively, that were kept at room temperature for 2 weeks. The samples containing 0.5 and 1% valine were clear at room temperature. Under different temperatures, for the same samples after 2 weeks at 45° C. the clearest samples were those prepared with 2-4% valine.

[0111] 5. Other Amino Acids (Cysteine, Glycine, and Proline)

[0112] Glycine and cysteine produced slightly turbid samples that remained stable at room temperature up to 2 weeks (date of this report). Phase separation occurred for such samples after 1-2 days at 45° C. In comparison, proline produced crystal clear samples that remained stable at room temperature for 10 days without any phase separation up to the date of this report. At 45° C., proline samples remained for up to 8 days with a phase separation occurring after 9 days for all samples with different proline concentrations except for that sample with 1% proline, which is still stable, but slightly turbid.

[0113] Two photographs were taken to show the various proline samples (0.5, 1, 2, 3 and 4%) which were kept at room temperature for 13 days. The photos helped confirm that the samples with higher proline (0.2 to 4%) are clear at room temperature. The same samples kept for 13 days at 45° C. showed a little phase separation/turbidity for all samples. Table 11 relates the results of comparative testing carried out for various proline-containing compositions and valine-containing compositions.

TABLE-US-00009 TABLE 9 Summary of the stability results at room temperature (ST: slightly turbid, T: Turbid) Side Initial Chain Amino Acid Observation Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 9 Day 14 No Amino Acid ST ST ST ST Positive Lysine N/A ST Arginine ST ST/T ST/T ST/T ST ST Histidine ST ST ST ST ST ST ST ST ST Negative Aspartic Acid ST ST ST ST ST Glutamic Acid ST ST ST ST ST ST ST ST ST Polar Serine ST ST/T ST Uncharged Asparagine ST ST ST/T ST Glutamine ST ST ST/T ST ST Nonpolar Tryptophan Insoluble Phenylalanine Leucine Insoluble Nonpolar Tyrosine ST ST ST ST/T ST T Methionine Clear CLEAR C/ST C/ST C/ST ST ST Alanine ST ST/T ST Valine CLEAR CLEAR CLEAR ST/C C/ST Others Cysteine ST ST ST ST ST ST ST Proline CLEAR CLEAR CLEAR C Glycine ST ST T

TABLE-US-00010 TABLE 10 Summary of the stability results at 45° C. Side Chain Amino Acid Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 9 Day 14 No Amino Acid ST ST ST ST ST Positive Lysine NA Arginine ST/T T/PS PS PS PS Histidine T/PS T/PS T/PS PS PS Negative Aspartic ST ST/T T/PS PS PS Glutamic T T/PS PS Polar Serine ST/T T/PS PS PS Uncharged Asparagine ST ST/T/PS T/PS PS PS Glutamine ST ST/PS T/PS PS PS Nonpolar Tryptophan Insoluble Phenylalanin Leucine Insoluble Tyrosine ST/PS T/PS PS PS PS Methionine ST ST/PS PS Alanine ST/T T/PS PS Valine ST/CL CLEAR CLEAR CLE CLE CLE PS/CLE PS/ PS/C Others Cysteine ST ST PS Proline ST/CL ST/CLE ST/CLE ST/C ST/C T/C ST/C ST/P ST/P Glycine ST/PS T/PS PS

TABLE-US-00011 TABLE 11 Effect of valine and proline concentrations on formula stability at 45° C. Valine Proline 0.5% 1% 2% 3% 4% 0.5% 1% 2% 3% 4% Day 1 C C C C C ST C C C C Day 2 C C C C C ST C C C C Day 3 C C C C C ST ST C C C Day 6 ST ST C C ST ST C C C C Day 7 T C C ST ST T T ST C C Day 8 PS PS C ST ST T T ST C C Day 10 PS PS C ST ST PS ST PS PS PS Day 13 PS C ST ST ST PS PS ST PS PS

[0114] In light of the above experiments, it was concluded that most amino acids do not significantly affect the turbidity of the formula at room temperature and produced slightly turbid solutions that were unstable at 45° C. Also, it was noted that only proline and valine produced crystal clear solutions that remained stable at room temperature with extended stability for some samples at 45° C. A third observation was that, over time, valine showed better stability than proline at 45° C.

[0115] According to a preferred embodiment of the present invention, the caustic composition can be used at temperatures ranging from 20 to 60° C. to perform CIP. Preferably, the time in the system (exposure time) is typically 60 minutes which is similar to conventional alkaline CIP. According to a preferred embodiment of the present invention, the composition is non-fuming, other advantages include the use of biodegradable surfactants as well as low concentration to increase the safety of the individuals handling the caustic compositions, this even though the concentrates have a pH of 14.

[0116] According to a preferred embodiment of the present invention, CIP cleaning methods using the cleaning composition of the present invention comprise: [0117] product discharge (water cleaning); [0118] alkali cleaning; [0119] water cleaning (intermediate rinsing); [0120] optionally acid cleaning, and [0121] water cleaning (intermediate rinsing).

[0122] According to a preferred embodiment of the present invention, CIP cleaning methods using the cleaning composition of the present invention can further comprise: [0123] sterilization cleaning (sodium hypochlorite, peracetic acid, iodine, hot water, etc.), [0124] water cleaning (final rinsing);

[0125] According to a preferred embodiment of the present invention, there is an intermediate rinse between cleaning and disinfecting of equipment with fresh water. This in-between rinse removes most of the detergent residue so that these residues do not interfere with the effectiveness of a subsequent acidic cleaning. According to a preferred embodiment, after an acidic cleaning step, it is desirable to rinse the equipment with fresh water. This rinse can also be done twice or more.

[0126] While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by those skilled in the relevant arts, once they have been made familiar with this disclosure that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.