Our sales team is often questioned about ABM’s inoculant packaging. They get questions such as, “Does the type of packaging really affect the viability of an inoculant?” and “What are the differences between jugs and bladders for liquid inoculants?”
Instead of focusing on the benefits and genetics of the organisms in these inoculants, our sales team dispels anxiety and myths about the packaging. So, let us cover the topic of jugs vs bladders so we all understand how and why certain packaging is chosen.
Rumor: Jugs are less gas permeable than bladders; therefore, they cannot support microbes.
Fact: Jugs are actually more gas permeable than bladders. The jugs we use are made of a plastic called high density polyethylene (HDPE). HDPE is a plastic that is extremely durable and allows 4000 ml/m2 of oxygen to pass per 24 hours. Bladders are made of Polylactide (PLA), which is also a durable plastic and allows 38-42 ml/m2 of oxygen to pass per 24 hours. The CO2 permeability of HDPE is also almost 90x higher than PLA. The low gas permeability of PLA bladders is what makes it desirable to the food industry – as it plays a large role in preventing spoilage.
Please note, the recycle code on each package signifies the type of material the container is made of. The chart below compares various types of plastic.
*MVTR stands for Moisture Vapor Transmission Rate in g-mil/100in. 2/24hr. MVTR is a measure of the passage of gaseous H2O through a barrier. The lower the rate, the longer the package protects its contents from moisture and ensures the moisture content of the product remains the same.
**O2 and CO2 stand for Oxygen Transmission Rate (OTR) and Carbon Dioxide Transmission Rate (COTR) in cm3-mil/m2/24hr. OTR and COTR are measures of the amount of gas that passes through a substance over a given period. The lower the readings, the more resistant the plastic is to letting gasses through.
Rumor: Because there is no air in the jug everything is DEAD.
Fact: Microbes used in inoculants are packaged in ways that allow for survival based on their physiology. For example, soybean and peanut inoculants’ organisms come from the genus Bradyrhizobium. This genus of bacteria is known to be slow growing and microaerophilic – allowing microbes with this trait to be packaged in low oxygen environments. Adapting to low oxygen environments is how these organisms have evolved to live below the soils crust or in legume roots where oxygen levels are low.
How Does the Organism Survive?
During inoculant production, bacteria is fermented in a tank with carbon and nitrogen sources, along with other nutrients. The carbon is used as an energy source for cellular reproduction. Oxygen utilization or respiration occurs at its highest level when cells are reproducing. By the time packaging occurs, there is virtually no usable carbon remaining in the growth medium. Instead, they go into a low respiratory state until returning to favorable conditions and required nutrients are present. This is why you should not see expanding bladders or jugs from metabolic gas production. Please note, the low respiratory state does not mean the organism is dead, but that it simply requires little oxygen to survive.
Choosing the Best Packaging System
Packaging should be a convenience to the end user. That is why we utilize both bladders and jugs for our inoculants. The type of packaging for each product is chosen based upon the volume of the product and ease-of-use to the farmer. If an organism is unable to survive in the packaging, we would be unable to use it in our processing. When buying an inoculant, we always recommend you inquire first about yields, genetics, and benefits of the organisms in the product. If all things are equal, go for ease-of-use.
Pros and Cons of Bladders vs. Jugs
If you have any further questions about jugs vs bladders, or any of our products, please contact us today.