DCT
1:21-cv-00079
Zeco LLC v. Enviro Tech Chemical Services Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Zeco, LLC, d/b/a Zee Company (Nevada)
- Defendant: Enviro Tech Chemical Services, Inc. (California)
- Plaintiff’s Counsel: Dewitt LLP
- Case Identification: 1:21-cv-00079, E.D. Tenn., 08/30/2022
- Venue Allegations: Venue is alleged to be proper in the Eastern District of Tennessee because Defendant sent patent infringement-related letters to Plaintiff's principal place of business in Chattanooga and sells products in the state.
- Core Dispute: Plaintiff seeks a declaratory judgment that its methods for treating poultry do not infringe Defendant’s patent and that the patent is invalid.
- Technical Context: The lawsuit concerns chemical methods used in poultry processing chill tanks to act as an antimicrobial and increase the final weight of the poultry product.
- Key Procedural History: The complaint alleges that Defendant made statements to the U.S. Patent and Trial Appeal Board (PTAB) during a prior proceeding that may limit the scope of its patent claims. It also alleges Defendant submitted declarations to the USPTO during prosecution stating that the claimed method was already in widespread use, which Plaintiff cites to support its invalidity contentions.
Case Timeline
| Date | Event |
|---|---|
| 2011-03-24 | U.S. Patent No. 10,912,321 Priority Date |
| 2016-XX-XX | Defendant allegedly sent letters to Plaintiff's customers regarding a forthcoming patent |
| 2021-02-09 | U.S. Patent No. 10,912,321 Issue Date |
| 2021-02-09 | Defendant allegedly sent letter to The Vincit Group (related to Plaintiff) |
| 2021-02-23 | Defendant allegedly sent letter to Plaintiff regarding a potential license |
| 2021-03-30 | Defendant allegedly sent letter to The Vincit Group and Plaintiff threatening enforcement |
| 2022-08-30 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 10,912,321 - Methods of Using Peracetic Acid to Treat Poultry in a Chill Tank During Processing
- Patent Identification: U.S. Patent No. 10,912,321, issued February 9, 2021.
The Invention Explained
- Problem Addressed: The patent addresses the standard industry practice of using peracetic acid (PAA) in poultry chill tanks at a low pH (around 4.5 to 5.5) for antimicrobial purposes, noting that this acidic environment is not optimal for maximizing the final weight of the processed poultry, a key economic driver for processing plants (’321 Patent, col. 5:10-29).
- The Patented Solution: The invention is a method that uses PAA in a chill tank but intentionally alters the water to a significantly higher, alkaline pH range (e.g., 7.6 to 10). This process, which involves adjusting the pH both before and after the poultry carcass is added, is described as unexpectedly increasing the weight of the poultry, thereby improving the processing plant's product yield, while maintaining antimicrobial efficacy (’321 Patent, Abstract; col. 6:30-39).
- Technical Importance: The method claims to provide the dual benefit of microbial control and increased product weight, which directly translates to increased revenue for high-volume poultry processors (’321 Patent, col. 5:58-64).
Key Claims at a Glance
- The complaint focuses its non-infringement arguments on independent claim 1 (Compl. ¶23).
- The essential elements of independent claim 1 are:
- Providing PAA-containing water in a reservoir.
- Before placing a poultry carcass in the water, determining and altering the water’s pH to about 7.6 to 10.
- Placing the poultry carcass into the pH-altered water.
- After placing the carcass in the water, again determining and altering the water's pH to about 7.6 to 10.
- Removing the poultry carcass from the water.
- Plaintiff seeks a declaration of non-infringement as to "any claim" of the patent, which would include all independent and dependent claims (Compl. p. 20).
III. The Accused Instrumentality
Product Identification
The accused instrumentality is the method for using PAA in poultry processing chill tanks that Plaintiff Zeco, LLC allegedly teaches its customers to perform (Compl. ¶30, 115).
Functionality and Market Context
- The complaint alleges that Plaintiff instructs its customers to mix PAA with an alkaline source to achieve a desired pH outside of the poultry chill tank, and then introduce the resulting solution into the tank (Compl. ¶31).
- A central allegation is that Plaintiff "does not recommend that its customers measure or adjust the pH of the solution in the poultry processing reservoir... before the poultry carcass is put into it" (Compl. ¶30). This alleged process functionality forms the primary basis for Plaintiff's non-infringement argument.
- The complaint identifies Plaintiff and Defendant as direct competitors selling chemical products to the poultry processing industry (Compl. ¶3).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
The declaratory judgment complaint frames its allegations around non-infringement. The following chart summarizes Plaintiff's theory of how its accused method avoids the limitations of the asserted patent claim.
’321 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Non-Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of treating at least a portion of a poultry carcass with peracetic acid, said method comprising the steps of: providing, in a reservoir, a peracetic acid-containing water... | Plaintiff's customers utilize PAA in a chill tank, which the patent defines as a reservoir. | ¶30 | col. 5:10-14 |
| after the step of providing the peracetic acid-containing water, determining the pH of the peracetic acid-containing water, and altering the pH of the peracetic acid-containing water to a pH of about 7.6 to about 10 by adding an alkaline source; | Plaintiff alleges it instructs customers to mix PAA and an alkaline source to a desired pH outside the chill tank and does not instruct them to determine or alter the pH of the water inside the tank before the carcass is added. | ¶30-32 | col. 62:38-42 |
| after the step of determining the pH and altering the pH of the peracetic acid-containing water, placing into the peracetic acid-containing water at least a portion of a poultry carcass; | Plaintiff's customers place poultry carcasses into the chill tank solution. | ¶30 | col. 62:43-46 |
| after the step of placing at least the portion of the poultry carcass into the peracetic acid-containing water, determining the pH of the peracetic acid-containing water in the reservoir with at least the portion of the poultry carcass therein, and altering the pH... | The complaint does not provide sufficient detail for analysis of this element, focusing its argument on the absence of the pre-carcass pH adjustment step. | N/A | col. 62:47-53 |
Identified Points of Contention
- Scope Questions: A primary dispute concerns the location of the first pH adjustment. The key question is whether the claim phrase "determining the pH of the peracetic acid-containing water" requires the measurement to occur within the "reservoir" (i.e., the chill tank), or if it can be satisfied by a measurement performed on the solution before it enters the tank. Plaintiff contends that Defendant made admissions during prior PTAB proceedings that limit this step to occurring "in the chill tank" (Compl. ¶34-36).
- Technical Questions: The case will involve factual questions regarding the precise instructions Plaintiff provides to its customers and the actual processes those customers implement. Evidence will be needed to establish whether any pH determination or alteration occurs inside the chill tank before a carcass is introduced.
V. Key Claim Terms for Construction
- The Term: "determining the pH of the peracetic acid-containing water" [in the context of the pre-carcass step]
- Context and Importance: The construction of this phrase is central to the non-infringement dispute. Plaintiff's entire theory rests on its contention that its instructed method performs pH adjustment outside the claimed "reservoir," while the patent requires it to be performed on the water already provided in the reservoir. Practitioners may focus on this term because its locational scope appears to be the dispositive issue for infringement.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language does not explicitly state "determining the pH in the reservoir." A party could argue that measuring the pH of a solution immediately before it enters the reservoir functionally satisfies the limitation.
- Evidence for a Narrower Interpretation: The claim recites a sequence where water is first provided "in a reservoir," and the next step is "determining the pH of the peracetic acid-containing water," which directly refers to the water just provided. The complaint points to alleged admissions made by the patentee during prosecution that the pH adjustment occurs "in the chill tank," which could give rise to a prosecution history disclaimer argument limiting the term's scope (Compl. ¶35-36).
VI. Other Allegations
- Indirect Infringement: Plaintiff seeks a declaration that it does not indirectly infringe. The basis for this is the argument that since the underlying method it teaches does not meet all the limitations of the patent claims, there is no direct infringement for Plaintiff to induce (Compl. ¶115).
- Willful Infringement: This is not alleged by Plaintiff. However, the complaint establishes that Defendant provided Plaintiff with actual notice of the patent and its infringement allegations, which would form the basis for a potential willfulness counterclaim by Defendant (Compl. ¶9, 11, 13).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim construction and prosecution history estoppel: can the claim limitation "determining the pH," which follows the step of "providing, in a reservoir, a peracetic acid-containing water," be met by a process where pH is adjusted outside the reservoir? The resolution may depend on whether the patentee's alleged statements during prior patent office proceedings created a binding disclaimer that limits the claim scope to actions performed strictly "in the chill tank."
- A second key issue will be one of validity based on prior public use: does the evidence, including alleged admissions made by the patentee's own declarants during prosecution that the claimed method was "almost uniformly adopted," demonstrate that the invention was obvious or anticipated by widespread industry practice before the patent's priority date?