ABSTRACT
Pathogens affecting raw milk from cows Claire Verraes, Sabine Cardoen and Wendie Claeys, Federal Agency for the Safety of the Food Chain, Belgium; and Lieve Herman, Institute for Agricultural and Fisheries Research, Belgium
1 Introduction
2 Pathogenic microorganisms in raw milk
3 Sources of microbiological contamination of raw milk
4 The growth of bacteria in raw milk
5 Heat treatment and other techniques to prevent bacterial contamination of milk
6 Occurrence of pathogenic microorganisms in raw milk and cheese made from raw milk
7 Outbreaks related to the consumption of raw milk and of cheese made from raw milk
8 Summary
9 Future trends
10 Where to look for further information
11 References
Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29 April 2004 laying down specific hygiene rules for food of animal origin defines ‘raw milk’ as milk produced by the secretion of the mammary gland of farmed animals that has not been heated to more than 40 ºC or undergone any treatment that has an equivalent effect. ‘Dairy products’ are defined as products resulting from the processing of raw milk or from the further processing of such products. According to this regulation, raw milk must come from animals that do not show any symptoms of infectious diseases communicable to humans through milk. These animals should show a good general state of health, present no sign of disease that might result in the contamination of milk and, in particular, should not suffer from any genital tract infection with discharge, enteritis with diarrhoea and fever or a recognizable inflammation of the udder. They must not have any udder wound that is likely to affect the milk. Raw milk must come from cows belonging to a herd that, within the meaning of Directive 64/432/EEC, is free or
officially free of brucellosis and of tuberculosis. The isolation of milk from the infected, or suspected of being infected, animals must be effective to avoid any adverse effect on other healthy animals’ milk. The requirements concerning hygiene on milk production holdings (premises and equipment, hygiene during milking, collection and transport and staff hygiene) are also described in Regulation (EC) N° 853/2004. The criteria for raw milk collected for industrial processing are as follows: A representative number of raw milk samples taken by random sampling must be checked, and the food business operators must initiate procedures to ensure that the samples meet the following criteria (for raw milk from cows): a plate count at 30 °C (per mL) ≤ 100 000 (rolling geometric average over a two-month period, with at least two samples per month); a somatic cell count (per mL) ≤ 400 000 (rolling geometric average over a three-month period, with at least one sample per month). When raw milk or dairy products undergo heat treatment, food business operators must ensure that this satisfies the requirements of Regulation (EC) N° 852/2004. Raw milk meant for consumption falls under the general food regulation, specifying that food must be free of pathogens.
