Milk-and-Dairy-Products-in-Human-Nutrition-FAO

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Milk and dairy products in human nutrition
Box 6.4
Lactoperoxidase system
Thermal pasteurization and cool storage are the main methods for safeguarding the
quality of milk in developed countries. However these methods are not always possible
in all countries and alternative methods are needed that are safe, cheap and
easily applicable under farm conditions. One such system is the LP system. The LP
system exploits antimicrobial compounds naturally present in milk by increasing the
concentrations of two components or activators (thiocyanate and hydrogen peroxide)
reacting with each other. This reaction is catalysed by the enzyme LP, which is naturally
present in milk, and leads to the formation of antibacterial compounds. The activation
of the LP system effectively extends the shelf-life of raw milk by 7-8 hours under ambient
temperatures of around 30 °C or longer at lower temperatures. The effectiveness
depends on the initial amount and type of microbiological contamination and the
temperature during the treatment period. The use of the LP system for preservation
of raw milk has been reported in several countries (Björck, Claesson and Schulthess,
1979; Thakar and Dave 1986; Fonteh et al., 2005). The use of the LP system is not
designed to replace adequate heat treatment, or remove the need for good hygiene
practices (FAO and WHO, 2006a), but has application where it is not possible to use
mechanical refrigeration for technical, and/or economic reasons. The LP system can
play an important role in preventing the spoilage of milk, in many regions of the world
where evening milk may be spoiled after storage overnight (Claesson, 1992; Jandal,
1997). The Codex guidelines for the preservation of raw milk by use of the lactoperoxidase
system [CAC/GL 13-1991] was adopted in 1991 (FAO and WHO, 1991).
milk or milk products post processing. Pathogens such as Listeria monocytogenes in
particular can survive and thrive in processing environments and contaminate milk
and dairy products during or after processing.
The control measures used for chemical and physical hazards in food are generally
preventive in nature and focus on avoiding and minimizing their presence rather
than elimination at a later stage. In addressing chemical hazards, attention should
be given to maintaining a clean production environment and safe feed and water to
reduce the potential introduction of chemical contaminants such as dioxins, heavy
metals and mycotoxins, as well as implementation of good animal husbandry and
practices to ensure that veterinary drugs, pesticides etc. do not exceed levels that
would present an unacceptable risk to the consumer.
Procedures and exchange of information are also required to ensure traceability
of the product. Codex Alimentarius defines traceability/product tracing as “the
ability to follow the movement of a food through specified stage(s) of production,
processing and distribution” (FAO and WHO, 2011c). In the event that there is
an outbreak of a food-borne illness, those responsible must be able to identify,
isolate and recall contaminated product. This often presents challenges both in the
highly organized milk and dairy industry in developed countries and in the lessorganized,
more-informal sector often seen in developing countries. In developed