Key Excerpts from Battelle's FlatPack Study on Comparative Shelf-Life
Excerpts From Battelle’s FlatPack Shelf-Life Study
These data indicate that the shelf-life (in months) for the FlatPack TSA was at least 6-fold greater than the Vendor A TSA when stored at room temperature.
There are developing countries in which electrical service is not wide-spread or reliable, and access to cold-storage facilities is limited. Therefore, being able to acquire culture plates that exhibit an extended shelf-life (i.e., >3 months) and maintain growth efficiency of microorganisms would be advantageous to overcome such deficiencies in infrastructure and unreliable product supply chains.
The long-term shelf-life evaluation [24 months] was performed using TSA plates from NanoLogix and Vendor A conducted over a two-year period. A sufficient number of TSA plates were procured from both vendors as a single production lot in order to conduct the two-year study.
The effect of different temperatures (cold, room temperature, desert hot) on the ability of TSA, BA, and CA to support bacterial growth was evaluated for 30 days. The temperature to simulate storage and transit conditions within a hot desert environment (60 °C) was chosen from the Department of Defense Test Method Standard for Environmental Engineering and Laboratory Tests (MIL-STD-810G; Climatic Category A2– Basic Hot).
The TSA FlatPacks stored at ambient conditions in a climate-controlled laboratory for 24 months supported the growth of B. anthracis Ames that ranged from 8.75 to 9.08 log CFU/mL (Figure1). Colony size and morphology was consistent with B. anthracis Ames at each time period tested. For the TSA FlatPacks, the plates were not observed to change in appearance or texture, and remained moist and soft over the 24 months. However, TSA from Vendor A had completely desiccated by the fourth month under ambient conditions (Figure 2); therefore, the initial batch of a single production lot could no longer be used for testing.
In many resource-limited nations throughout the world, clinical sample analysis and public health surveillance revolves around the central reference laboratory (CRL) principle in which this main laboratory is typically located in the capital with several intermediate and/or peripheral facilities throughout the rest of the nation [6]. The CRL typically commands most of the resources, whereas the more remote laboratories are often under-equipped, lack the adequate infrastructure, possess little to no standardization, and are subject to deficiencies in the supply chain of consumables [7-9]. Consequences resulting from these deficiencies could lead to the degradation or expiration of critical laboratory consumables such as agar media used for the isolation, identification, and antimicrobial susceptibility testing needed for clinical diagnosis. Under circumstances in which media cannot be prepared fresh at each time of use or are supplemented with compounds susceptible to degradation, enhancing the shelf-life and stability of critical reagents and consumables for peripheral laboratories in resource-limited nations would be advantageous logistically and monetarily.
For decades, the food industry has studied the effects of modified atmosphere packing (MAP) to extend the shelf-life of fresh or processed foods [10-12]. The MAP process typically reduces the level of oxygen in the packaged items by replacing with nitrogen, carbon dioxide, argon, or a combination of these gases with the intent of maintaining appearance, texture, flavor, and nutritive value. Following the basic MAP principle, the FlatPacks tested in this study are vacuum-sealed in nylon/polyethylene pouches and flushed with nitrogen in order to extend shelf-life of both general-purpose and enrichment media.
[The TSA FlatPacks] supported the growth of B. anthracis in which the mean concentration (9.03 log CFU/mL) at 24 months was within 1.2% of the mean concentration (8.92 log CFU/mL) at Day 0. In contrast, TSA plates from Vendor A were desiccated and not useable at the 4-month time point; therefore, new plates had to be purchased from Vendor A for each subsequent time point, which prevented a true room temperature shelf-life determination over the 24-month investigation. These data indicate that the shelf-life (in months) for the FlatPack TSA was at least 6-fold greater than the Vendor A TSA when stored at room temperature.
Based on results of this study, the FlatPack packaging extends the shelf-life of TSA stored at room temperature when compared to a common form of packaging (i.e., Vendor A). Moreover, the FlatPacks containing TSA and the enriched media BA and CA support bacterial growth for at least 30 days when stored under extreme “hot” temperatures. [60 degrees Celsius or 150 degrees Fahrenheit].
Excerpts From Battelle’s FlatPack Shelf-Life Study
These data indicate that the shelf-life (in months) for the FlatPack TSA was at least 6-fold greater than the Vendor A TSA when stored at room temperature.
There are developing countries in which electrical service is not wide-spread or reliable, and access to cold-storage facilities is limited. Therefore, being able to acquire culture plates that exhibit an extended shelf-life (i.e., >3 months) and maintain growth efficiency of microorganisms would be advantageous to overcome such deficiencies in infrastructure and unreliable product supply chains.
The long-term shelf-life evaluation [24 months] was performed using TSA plates from NanoLogix and Vendor A conducted over a two-year period. A sufficient number of TSA plates were procured from both vendors as a single production lot in order to conduct the two-year study.
The effect of different temperatures (cold, room temperature, desert hot) on the ability of TSA, BA, and CA to support bacterial growth was evaluated for 30 days. The temperature to simulate storage and transit conditions within a hot desert environment (60 °C) was chosen from the Department of Defense Test Method Standard for Environmental Engineering and Laboratory Tests (MIL-STD-810G; Climatic Category A2– Basic Hot).
The TSA FlatPacks stored at ambient conditions in a climate-controlled laboratory for 24 months supported the growth of B. anthracis Ames that ranged from 8.75 to 9.08 log CFU/mL (Figure1). Colony size and morphology was consistent with B. anthracis Ames at each time period tested. For the TSA FlatPacks, the plates were not observed to change in appearance or texture, and remained moist and soft over the 24 months. However, TSA from Vendor A had completely desiccated by the fourth month under ambient conditions (Figure 2); therefore, the initial batch of a single production lot could no longer be used for testing.
In many resource-limited nations throughout the world, clinical sample analysis and public health surveillance revolves around the central reference laboratory (CRL) principle in which this main laboratory is typically located in the capital with several intermediate and/or peripheral facilities throughout the rest of the nation [6]. The CRL typically commands most of the resources, whereas the more remote laboratories are often under-equipped, lack the adequate infrastructure, possess little to no standardization, and are subject to deficiencies in the supply chain of consumables [7-9]. Consequences resulting from these deficiencies could lead to the degradation or expiration of critical laboratory consumables such as agar media used for the isolation, identification, and antimicrobial susceptibility testing needed for clinical diagnosis. Under circumstances in which media cannot be prepared fresh at each time of use or are supplemented with compounds susceptible to degradation, enhancing the shelf-life and stability of critical reagents and consumables for peripheral laboratories in resource-limited nations would be advantageous logistically and monetarily.
For decades, the food industry has studied the effects of modified atmosphere packing (MAP) to extend the shelf-life of fresh or processed foods [10-12]. The MAP process typically reduces the level of oxygen in the packaged items by replacing with nitrogen, carbon dioxide, argon, or a combination of these gases with the intent of maintaining appearance, texture, flavor, and nutritive value. Following the basic MAP principle, the FlatPacks tested in this study are vacuum-sealed in nylon/polyethylene pouches and flushed with nitrogen in order to extend shelf-life of both general-purpose and enrichment media.
[The TSA FlatPacks] supported the growth of B. anthracis in which the mean concentration (9.03 log CFU/mL) at 24 months was within 1.2% of the mean concentration (8.92 log CFU/mL) at Day 0. In contrast, TSA plates from Vendor A were desiccated and not useable at the 4-month time point; therefore, new plates had to be purchased from Vendor A for each subsequent time point, which prevented a true room temperature shelf-life determination over the 24-month investigation. These data indicate that the shelf-life (in months) for the FlatPack TSA was at least 6-fold greater than the Vendor A TSA when stored at room temperature.
Based on results of this study, the FlatPack packaging extends the shelf-life of TSA stored at room temperature when compared to a common form of packaging (i.e., Vendor A). Moreover, the FlatPacks containing TSA and the enriched media BA and CA support bacterial growth for at least 30 days when stored under extreme “hot” temperatures. [60 degrees Celsius or 150 degrees Fahrenheit].
