Comparison Table of Candidates for Automated Colony Counters Using Application-Specific Requirements
| Characteristic | Desired Attribute | Traditional Human Reading | HD-Camera and Illumination only | HD-Camera and Illumination in Conjunction with Intrinsic Autofluorescence |
|---|---|---|---|---|
| Monitoring and Reporting | Continuous monitoring, reporting of failure immediately | Dependent on FTE, interim reads possible but time demanding, results read, transcribed, and verified by second operator (contemporaneous verification) | Every plate is read every hour | Every plate is read every 4 hours |
| Immediate notification (e.g., email, visual) of CFU growth when user-defined alert and action levels are reached | Immediate notification (e.g., email, visual) of CFU growth when user-defined alert and action levels are reached | |||
| Proprietary instrument | No—multiple vendors | No | Yes | Yes |
| Proprietary Consumables | No—multiple vendors | No | Yes | Yes, plates have a specific design to allow for consistent orientation and movement of the plates using the robotic system |
| In theory, the platform is open for use with generic consumables, but full functionality is only available if proprietary material is used. Plates need to be clear (without any markings) and have a GS1 compliant barcode located on the side of the plate | ||||
| Media Availability | All relevant media available in formulations according to pharmacopoeias | Yes | Yes | Yes |
| Detection - Specificity | Detects a broad panel of isolates especially from past issues, patient events, recalls | Detects a broad panel of mesophilic bacteria, yeasts, and molds | Validation data demonstrates that the system detects a broad panel of mesophilic bacteria, yeasts, and molds | Validation data demonstrates that the system detects a broad panel of mesophilic bacteria, yeasts, and molds |
| Maximum Samples at a Time | As high as possible (need must be defined by end user) | Incubation: dependent on space | Up to 300 plates per instrument. Two configurations are possible: a single-incubation temperature or a two-temperature cycle | Testing and Incubation: Approximately 700 plates (in two incubator units) |
| Reads: Depends on number of FTE and operator speed (60–100/hour) | Note: When using a two-temperature incubation condition, the capacity is approximately 350 plates | |||
| Time To Result | ≤ Traditional methods | Compendial minimum for EM, Bioburden TAMC and TYMC (3–5 days) | Positives in as little as 5 hours (fast growers) | Positives in as little as 12–16 hours (fast growers) |
| Based on pharmacopoeial requirements, earliest negatives can be obtained in 3–5 days | Earliest negatives can be obtained after 36 hours (Health Agency approvals for microbial enumeration tests with a reduced incubation time of 36 hours for product samples—IPC as well as release samples - obtained) | |||
| The incubation time will be qualified at a customer site; data may demonstrate that final results can be reported faster with the equipment compared with the standard method—this will be site / customer specific | Note: incubation for e.g., testing of water samples must be validated | |||
| Result Reporting | Automatic, integrated with LIMS | Manual transcription and verification | Results can be transferred automatically to LIMS | Results can be transferred automatically to LIMS |
| Easy to Use—Human Error Prevention | Fewer potential human error sources compared with existing. | Reduced through quality of training, LIMS mistake-proofing, real-time review prior to on-test, verification at off-test | Fully automated and objective | Fully automated and objective |
| Errors subject to FTE skill, experience, acuity, etc. | No scope for human error in the reading and analysis of plates by the instrument. | Software includes human error prevention prompts. Control screen provides user guidance and feedback prompts to user. | ||
| Connection to LIMS avoids data transcriptions errors | Connection to LIMS avoids data transcriptions errors | |||
| Preventative Maintenance | ≤ every 6 months | Incubators: Temp control, humidity control, lighting, doors, gaskets, temperature indicators, alarm systems | Annual | Bi-annual |
Abbreviations: EM, environmental monitoring; FTE, full-time employee; HD, high definition; LIMS, laboratory information management system; GS1, the foundational GS1 standard that defines how identification keys, data attributes and bar codes must be used in business applications; TAMC, total aerobic microbial count;TYMC, total combined yeasts/ moulds count; IPC, in-process control.