Microbiological safety of goat milk and cheese: Evidences from a meta-analysis

Abstract

This chapter synthesizes published information concerning the incidence of zoonotic pathogenic microorganisms-Listeria monocytogenes, Staphylococcus aureus and shigatoxin-producing Escherichia coli-in raw goat milk and cheese. Meta-analytical data were extracted from primary studies undertaken in Brazil, China, Czech Republic, Germany, Iran, Italy, Malaysia, Mexico, Norway, Portugal, Spain, Sweden, Switzerland, Turkey and USA. In both raw goat milk (overall incidence 42.6%; 95% CI: 23.0-64.8%) and cheese (overall incidence 26.4%; 95% CI: 10.8-51.6%), S. aureus was found to be the most frequent contaminant bacterium, which suggests that control measures during milk handling are still to be reinforced. In addition, the high frequency of detection of generic E. coli in raw goat milk cheese (overall incidence 11.9%; 95% CI: 3.8-31.6%) is another indicator of hygiene deficiencies during production. Moreover, E. coli strains with virulence genes have been very frequently detected in raw goat milk (overall incidence 10.5%; 95% CI: 5.3-19.6%). L. monocytogenes, a pathogen that mainly affects the susceptible population, presented a high incidence in both raw goat milk (overall incidence 3.4%; 95% CI: 2.2-5.1%) and goat milk cheese (overall incidence 8.5%; 95% CI: 4.9-14.6%). In conclusion, the present meta-analysis confirms that raw goat milk and cheese are important vehicles of transmission of foodborne diseases. Further research work towards improving the current microbiological quality of these products, particularly in traditional production units, is essential.