Cow’s milk has been part of human diet for a long time. However, raw milk has been associated with various foodborne outbreaks particularly due to bacterial pathogens. Microorganisms in milk are originated from the udder of cattle and as a result of contamination from inadequately cleaned and sanitized teat, milking equipment, air, soil, or workers. Milk obtained under hygienic conditions generally has microorganisms in the range of 103-104 CFU/ml, while that obtained under less hygienic may contain >106 CFU/ml. Raw milk generally contains psychrotrophic, thermoduric and thermophilic microorganisms and occasionally contains pathogens. A survey on raw milk samples from 248 dairy farmers in Pennsylvania, US, found Campylobacter jejuni in 2% of the samples, Shiga toxin producing Escherichia coli (STEC) in 2.4%, Listeria monocytogenes in 2.8%, Salmonella in 6%, and Yersinia enterocolitica in 1.2% samples; while 12% of the samples contained more than one pathogen. Despite the fact that pasteurization has improved the safety of milk; various countries still allow the distribution of raw milk under strict requirements. A 13-year study in the US reported 121 milk-related outbreaks with known food sources and etiological agents. Although pasteurized milk could cause outbreaks, a higher percentage (60%) of the outbreaks was caused by unpasteurized milk and cheese. A higher milk-borne outbreak rate (75%) also occurred in the US states that allow distribution of raw milk to the retail level. The study also suggested that the most predominant etiologic agent in nonpasteurized milk outbreaks was Campylobacter spp while those in pasteurized milk outbreaks was Norovirus. Raw milk consumption should be avoided when there is no confidence on the herds’ and/or farm supervision.
Susu adalah cairan bergizi
berwarna putih yang
dihasilkan oleh kelenjar susu
mamalia. Sejarah mencatat bahwa
manusia di Eropa Tengah telah
mengonsumsi susu sapi sejak
ribuan tahun yang lalu. Pada
4000 tahun sebelum Masehi telah
ditemukan bukti-bukti bahwa
manusia memerah susu sapi.
Dengan 3.25% protein, 4.2% lemak,
4.6% laktosa, 0.65% mineral dan
87.3% air, susu sapi termasuk
bahan pangan yang lengkap
kandungan gizinya. Akan tetapi
kandungan gizi tersebut, ditambah
faktor-faktor lainnya, juga sangat
mendukung pertumbuhan
mikroorganisme termasuk bakteri
patogen, sehingga konsumsi susu
segar (mentah) telah dihubungkan
dengan berbagai outbreak
penyakit bawaan pangan. Proses
pasteurisasi yang dikembangkan
oleh Louis Pasteur pada 1822-1895
berhasil meningkatkan keamanan
mikrobiologi susu, akan tetapi
proses ini pun harus dikendalikan
dengan baik agar tidak terjadi
kontaminasi pasca pasteurisasi.
Oleh: Prof. Ratih Dewanti-HariyadiProfesor Mikrobiologi Pangan
Departemen Ilmu dan Teknologi Pangan
Peneliti SEAFAST Center, Institut Pertanian Bogor
Selengkapnya artikel ini dapat dibaca di majalah FOODREVIEW INDONESIA edisi Juni 2015, yang dapat diunduh di www.foodreview.co.id