Raw milk and raw milk cheeses as vehicles for infection by Verocytotoxin‐producing Escherichia coli

Abstract

Raw milk and raw milk cheeses can be a source of food-borne pathogens, including Verocytotoxin (Shiga toxin)-producing Escherichia coli (VTEC ⁄ STEC). Outbreaks of VTEC O157: H7 infections have been attributed to the consumption of raw milk and associated dairy products. Although the general prevalence of VTEC O157 in raw milk and raw milk cheeses is low, it can be higher for non-O157 VTEC. The clinical significance of many of these VTEC is unclear, although some are associated with disease. Studies show that E. coli O157 strains can survive the various stages of the cheesemaking process and that raw milk and raw milk cheeses remain a potential vehicle for VTEC infections.

Detection of Shiga Toxin-Producing Escherichia coli Serotypes O26:H11, O103:H2, O111:H8, O145:H28, and O157:H7 in Raw-Milk Cheeses by Using Multiplex Real-Time PCR

“…Domestic ruminants have long been identified as a major reservoir for STEC (29). Although STEC transmission to humans is frequently associated with consumption of raw or undercooked meat, raw milk and dairy products have also been implicated in human disease (4). Detection and isolation of STEC in foodstuffs by traditional culture methods is rather laborious and time-consuming and is complicated by the lack of common biochemical characteristics distinguishing most STEC from other E. coli strains.…”

Survey of Minas frescal cheese from Southwest Minas Gerais for virulence factors and antimicrobial resistance in Escherichia coli isolates

“…None of the E. coli isolates examined by PCR amplifi cation showed the presence of stx1, stx 2 or eae encoding genes, what means there is no STEC strains among the cheese isolates tested, as shown in table 2. Different cheese varieties have lead evidence of STEC contamination based on presence of stx gene or isolated STEC (BAYLIS, 2009). In France a cluster of four cases of haemolytic uraemic syndrome (HUS) in children, caused by E. coli O157-VT2 was traced to consumption of cheese made with unpasteurized mixed cows' and goats' milk (DESCHÊNES et al, 1996).…”

“…Cattle are an important reservoir of toxigenic E. coli, and have been implicated as a source of E. coli that infect and cause disease in human beings (BAYLIS, 2009). The aims of the present study were to determine the presence of STEC and ExPEC strains in Minas frescal cheese and also to verify the resistance of E. coli strains isolated from cheese to antimicrobial drugs.…”

“…The STEC strains can gain access to milk by fecal contamination or by direct excretion (mastitis) from the udder into the milk (LIRA et al, 2004). Outbreaks and sporadic cases of illnesses have been traced to consumption of STEC-contaminated cheese (BAYLIS, 2009).…”

Microbial species of safety concern in milk from informal processors in Harare, Zimbabwe

“…Consumption of unprocessed milk and its by-products is potentially hazardous and has been associated with several types of infections including brucellosis (Ramos et al, 2008), tuberculosis (Doran et al, 2009), salmonellosis (Poppe, 2011), yersinosis (Greenwood and Hooper, 1990), Escherichia coli O157:H7 (Anand and Griffiths, 2011) and staphylococcal enterotoxins poisoning (Baylis, 2009;Ostyn et al, 2010). Despite modern dairy ensuring that consumers get processed safe milk, consumption of unprocessed milk is still common in Zimbabwe especially in the rural areas with the two main types being fresh liquid milk and naturally fermented milk.…”