It has been established that the development of high readings for Trichloromethane (TCM) arises from the cleaning and disinfecting procedures that use solvents containing active chlorine.
Active chlorine is still one of the most effective and economical antimicrobial compounds. However, the use of cleaning and disinfection solutions containing active chlorine can lead to a further reaction, resulting in an unintentional side effect, ie the development of high TCM readings.
If active chlorine comes in contact with an organic material, such as milk, chlorine binds to it and forms total organic chlorine, which includes TCM. Thus, TCM can develop within the cleaning and disinfection solution.
If this cleaning and disinfection solution is not removed completely from the equipment by rinsing, then TCM will be transferred to the milk that subsequently comes in contact with those surfaces. When TCM contaminates raw milk, it tends to be associated with the fat phase and, therefore, accumulates in high fat products subsequently manufactured, eg cream and butter.
Research findings
The level of TCM in a milk tanker load is dependent on the TCM levels of the individual milk collections making up that load. This is particularly important for milk producers and processors. It shows that it is critical that each milk supplier takes responsibility for their milk TCM level. Milk from one supplier that is high in TCM, when added to a milk tanker load with acceptable TCM level (less than 0.002mg/kg in milk) can result in all of the milk in that load being measured as high in TCM (greater than 0.002mg/kg).A reduction in rinse water volume from 14 to seven litres/milking unit resulted in an increase in milk TCM concentration. However, bulk milk TCM was not affected when the rinse water volume was increased from 14 to 16.5 litres/milking unit. Therefore, the currently recommended rinse water volume (14 litres/milking unit) was found to be satisfactory in minimising milk TCM residues. But this information needs to be taken in association with the current advice, which states that the first 4.5 litres of milk, at the start of milking, should be run to waste. Increased concentrations of hypochlorite (steriliser) in the final rinse water of milking machine wash routines caused an increase in the formation of TCM in milk. Peracetic acid can be used as a steriliser in the final rinse water as an alternative to chlorine.Control of TCM in milk on-farm
Use suitable cleaning and disinfection products with acceptable correct chlorine content (refer to Teagasc list of Detergent Analysis).Mix cleaning and disinfection product correctly (use a measuring cup) and according to advice on the container (nine litres of detergent-water mix/cluster). Use sufficient clean rinse water (14 litres per milking unit) to remove milk residue before detergent circulation. Do not re-use detergent more than once. Use sufficient clean rinse water (14 litres per milking unit) to remove detergent after wash cycle.Use the same caution in washing bulk tanks as milking machines.Service your bulk tank regularly; ensure correct setting for sufficient rinse water and correct detergent usage.Peracetic acid may be used as an alternative steriliser to hypochlorite in the final rinse water, if required.Peracetic acid may be used as an alternative to hypochlorite for cluster dipping if this practice is being carried out.Success to date in reducing milk TCM levels has been due to joint co-operation between producers, processors and Teagasc.
It has been achieved through routine screening for TCM in both tanker milk and individual supplier milk; farm visits to identify incorrect practices, allied with advice on the correct practices, and a vigorous advisory campaign through Teagasc and the co-ops.
Milk processors are following a protocol in which tanker milk is tested for TCM. Those high in TCM are identified. Milk from farms contributing to those tankers are then tested for TCM and thus herd milk high in TCM is identified. These are then targeted with advice, assistance and further testing to reduce TCM levels.
An intensive analysis programme is in place with approximately 25,000 milk samples tested for TCM during 2011. TCM in butter has been reduced very significantly over the last four years (from 0.07 mg/kg to 0.03 mg/kg) which has allowed the continued demand for Irish butter in export markets.
Future
It is vitally important that TCM levels are maintained low as future specifications for acceptable levels in product are likely to be reduced. It is necessary to maintain TCM levels of <0.002 mg/kg in milk to ensure that TCM never exceeds 0.03 mg/kg in the butter product. This means elimination of almost all chlorine residues in milk. It is expected that in excess of 25,000 milk samples will be screened for TCM in 2012.
Problem
The TCM developed in milk is concentrated in the fat fraction during product manufactureTCM levels in Irish butter have always been well within legal requirements but European competitors and consumers are requiring a maximum level of 0.03 mg/kg.To maintain a position of dominance in the butter market, it is necessary to reduce TCM levels in butter to 0.03 mg/kg, which effectively means reducing TCM levels in milk to <0.002 mg/kg.Key points
TCM is a residue in milk caused by interaction of chlorine (from washing detergent) and milk.
TCM in milk must be <0.002 mg/kg. If levels are higher, then check the following critical factors influencing TCM development in milk:
Type of product used for cleaning and disinfection should be from a reputable supplier.Avoid use of high chlorine products (refer to Teagasc list of detergent analysis).Volume used and method of mixing of product is critical.Sufficient rinsing of milk from surface before detergent circulation – 14 litres/milking unit.Sufficient rinsing of detergent from surface after detergent circulation – 14 litres/milking unit.Cluster dipping in chlorine-based product should not be used.Avoid using hypochlorite as a sterilizer in the final rinse water of the milking machine wash routine.Do not add additional chlorine to the wash solution.*B O’Brien, D Gleeson and K Jordan, Teagasc Animal and Grassland Research and Innovation Centre, Teagasc Food Research Centre, Moorepark, Fermoy, Co Cork
This story was first published in 2012
It has been established that the development of high readings for Trichloromethane (TCM) arises from the cleaning and disinfecting procedures that use solvents containing active chlorine.
Active chlorine is still one of the most effective and economical antimicrobial compounds. However, the use of cleaning and disinfection solutions containing active chlorine can lead to a further reaction, resulting in an unintentional side effect, ie the development of high TCM readings.
If active chlorine comes in contact with an organic material, such as milk, chlorine binds to it and forms total organic chlorine, which includes TCM. Thus, TCM can develop within the cleaning and disinfection solution.
If this cleaning and disinfection solution is not removed completely from the equipment by rinsing, then TCM will be transferred to the milk that subsequently comes in contact with those surfaces. When TCM contaminates raw milk, it tends to be associated with the fat phase and, therefore, accumulates in high fat products subsequently manufactured, eg cream and butter.
Research findings
The level of TCM in a milk tanker load is dependent on the TCM levels of the individual milk collections making up that load. This is particularly important for milk producers and processors. It shows that it is critical that each milk supplier takes responsibility for their milk TCM level. Milk from one supplier that is high in TCM, when added to a milk tanker load with acceptable TCM level (less than 0.002mg/kg in milk) can result in all of the milk in that load being measured as high in TCM (greater than 0.002mg/kg).A reduction in rinse water volume from 14 to seven litres/milking unit resulted in an increase in milk TCM concentration. However, bulk milk TCM was not affected when the rinse water volume was increased from 14 to 16.5 litres/milking unit. Therefore, the currently recommended rinse water volume (14 litres/milking unit) was found to be satisfactory in minimising milk TCM residues. But this information needs to be taken in association with the current advice, which states that the first 4.5 litres of milk, at the start of milking, should be run to waste. Increased concentrations of hypochlorite (steriliser) in the final rinse water of milking machine wash routines caused an increase in the formation of TCM in milk. Peracetic acid can be used as a steriliser in the final rinse water as an alternative to chlorine.Control of TCM in milk on-farm
Use suitable cleaning and disinfection products with acceptable correct chlorine content (refer to Teagasc list of Detergent Analysis).Mix cleaning and disinfection product correctly (use a measuring cup) and according to advice on the container (nine litres of detergent-water mix/cluster). Use sufficient clean rinse water (14 litres per milking unit) to remove milk residue before detergent circulation. Do not re-use detergent more than once. Use sufficient clean rinse water (14 litres per milking unit) to remove detergent after wash cycle.Use the same caution in washing bulk tanks as milking machines.Service your bulk tank regularly; ensure correct setting for sufficient rinse water and correct detergent usage.Peracetic acid may be used as an alternative steriliser to hypochlorite in the final rinse water, if required.Peracetic acid may be used as an alternative to hypochlorite for cluster dipping if this practice is being carried out.Success to date in reducing milk TCM levels has been due to joint co-operation between producers, processors and Teagasc.
It has been achieved through routine screening for TCM in both tanker milk and individual supplier milk; farm visits to identify incorrect practices, allied with advice on the correct practices, and a vigorous advisory campaign through Teagasc and the co-ops.
Milk processors are following a protocol in which tanker milk is tested for TCM. Those high in TCM are identified. Milk from farms contributing to those tankers are then tested for TCM and thus herd milk high in TCM is identified. These are then targeted with advice, assistance and further testing to reduce TCM levels.
An intensive analysis programme is in place with approximately 25,000 milk samples tested for TCM during 2011. TCM in butter has been reduced very significantly over the last four years (from 0.07 mg/kg to 0.03 mg/kg) which has allowed the continued demand for Irish butter in export markets.
Future
It is vitally important that TCM levels are maintained low as future specifications for acceptable levels in product are likely to be reduced. It is necessary to maintain TCM levels of <0.002 mg/kg in milk to ensure that TCM never exceeds 0.03 mg/kg in the butter product. This means elimination of almost all chlorine residues in milk. It is expected that in excess of 25,000 milk samples will be screened for TCM in 2012.
Problem
The TCM developed in milk is concentrated in the fat fraction during product manufactureTCM levels in Irish butter have always been well within legal requirements but European competitors and consumers are requiring a maximum level of 0.03 mg/kg.To maintain a position of dominance in the butter market, it is necessary to reduce TCM levels in butter to 0.03 mg/kg, which effectively means reducing TCM levels in milk to <0.002 mg/kg.Key points
TCM is a residue in milk caused by interaction of chlorine (from washing detergent) and milk.
TCM in milk must be <0.002 mg/kg. If levels are higher, then check the following critical factors influencing TCM development in milk:
Type of product used for cleaning and disinfection should be from a reputable supplier.Avoid use of high chlorine products (refer to Teagasc list of detergent analysis).Volume used and method of mixing of product is critical.Sufficient rinsing of milk from surface before detergent circulation – 14 litres/milking unit.Sufficient rinsing of detergent from surface after detergent circulation – 14 litres/milking unit.Cluster dipping in chlorine-based product should not be used.Avoid using hypochlorite as a sterilizer in the final rinse water of the milking machine wash routine.Do not add additional chlorine to the wash solution.*B O’Brien, D Gleeson and K Jordan, Teagasc Animal and Grassland Research and Innovation Centre, Teagasc Food Research Centre, Moorepark, Fermoy, Co Cork
This story was first published in 2012
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