ASTM E1839-20 Standard Practice for Effectiveness of Slimicides in the Paper Industry - Bacterial and Fungal Slime

The American Society for Testing and Materials (ASTM) standard "ASTM E1839-20 Standard practice for effectiveness of slimes in the paper industry - Bacterial and fungal slimes" describes a procedure for evaluating the effectiveness of slimes for the control of bacterial and fungal slimes (slime or mud) in paper mill systems and similar systems. It is the responsibility of the researcher to determine if good laboratory practices (GLP) are necessary and to follow them where appropriate.

For the purposes of this standard, in addition to the terms and definitions given in the "ASTM E2756-19 Standard Terminology for Antimicrobial and Antiviral Agents" standard, the following definitions apply:

• The slurry of pulp fed into the paper machine. The type of pulp (sulphite, kraft, mechanical), the fiber source (virgin, recycled including pre- or post-consumer waste paper), and the pH value are used to specify a particular type of pulp.
• A microbicide is a physical or chemical agent that kills microorganisms.
• Pulp is wood that has been separated into its fibrous components by chemical or mechanical means. After certain processes, the pulp is used to make paper, paperboard, or pulpboards. Hardwood pulp is made from trees such as maple or oak, and softwood pulp is produced from trees such as pine.
• Pulp slurry is an aqueous combination of cellulose fibers, fillers and other additives used for certain grades of paper.
• Slime (mucus or slime) is a biofilm.
• Slime killers (silicides) are chemicals added during pulp and paper processing to reduce the growth of slime-forming microorganisms.

In performing tests, bacterial cells or fungal spores are added to acid or alkaline pulp slurries or both are treated with slimicides to achieve final concentrations of 2 × 106 to 1 × 107 bacteria/mL or 105 to 106 fungal spores/mL and incubated at the appropriate temperature for specified time intervals. Aliquots of the test suspension are then neutralized, placed on bacterial or fungal media, and observed for growth. Results with the biocide are compared to results without the biocide (control). As a performance standard, an effective slimicide is one that shows a sustained reduction in bacterial and fungal numbers relative to the control throughout the duration of the test.

This standard practice is used to determine if a slime control agent has an application for the control of bacterial or fungal slime or biofilm in the paper industry. This practice is run under acid, alkaline, or acid and alkaline conditions to determine the effectiveness of the slime control agent. Test conditions may be modified to reflect intended usage patterns in typical paper mill systems, including the use of actual paper mill materials.

The main equipment used in these tests includes:

• Plant scale: A platform scale for weighing test materials and bottles, accurate to 200 g on a 0,1 g load.
• Analytical balance: A balance with a sensitivity of 0,1 mg used to weigh candidate slime control agents.
• Sample cups (sterile): 120 mL plastic sample cups with screw caps are ideal for holding test materials. Other suitable containers include 150/160 mL milk diluent bottles.
• Culture dishes: Petri dishes, tissue culture flasks or glass tubes (15 × 125 mm or 18 × 150 mm without lips, preferably of borosilicate glass).
• Caps for tubes and containers.
• Shredders.
• Flame equipment: Depending on the conditions, an alcohol lamp may be used to flame vaccine needles and other equipment. A Bunsen burner or electric incinerator may be used.
• Incubators capable of maintaining temperatures between 28 degrees and 70 degrees plus/minus 2 degrees to ensure appropriate incubation temperatures. The temperature should be consistent with the temperature of the product to be preserved.
• pH meter: Any meter suitable for standardizing the pH value of culture media.
• Pipettes: 1,1 mL milk diluent type, 0,01 mL graduated at 1,0 mL, and 0,1 mL pipettes graduated at 10 mL can be used, but not for high viscosity materials.
• Pipetting aid: A rubber bulb or other device for transferring liquid.
• Sterilizers: Pressure steam sterilizer or hot air oven that can operate at 180 degrees plus/minus 2 degrees for 2 hours plus/minus 0,2 hours.
• Filter apparatus for filter sterilization: Disposable filter units.
• Sterile funnel with sterile glass wool or sterile cotton gauze for filtering spores.
• A manual colony counter or proven colony image analyzer (electronic/scanner type) is suitable for counting plates after incubation.
• Sterile swabs to aid in the removal of fungal spores from the agar surface.
• Hemocytometer for counting spore suspension.
• Microscope providing a magnification range of 400 to 1000X with a suitable light source. Phase contrast or darkfield capability may be required.
• Constant temperature shaker: A reliable constant temperature shaker (water bath or incubator type) should be used to ensure mixing and aeration and to maintain the selected temperature (plus/minus 2 degrees) throughout the contact period.
• Mechanical stirrers: Magnetic or propeller type stirrers or other suitable devices.

In short, chemical products are introduced into the system to prevent the growth of microorganisms in paper machines and to eliminate the harmful effects they produce. The most commonly used chemical products are dispersants and biocides.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also testing services within the scope of the "ASTM E1839-20 Standard application for the effectiveness of slimicides in the paper industry - Bacterial and fungal slime" standard.