A Risk Assessment ofEscherichia ColiO157:H7 in Ground Beef

Is the prevalence and shedding concentrations of E. coli O157 in beef cattle in Scotland seasonal?

“…However, we must treat this result with caution because this difference in shedding concentration is due to a few high shedding cattle and as such, further studies are required to determine the significance of this result. Investigations into the presence of E. coli O157 in retail foods have also shown a greater prevalence during summer where in a 12 month study Chapman et al [15] found 82% of retail meats testing positive for E. coli O157 were collected between May and September and in US [4] workers found ground beef samples were three times as likely to contain E. coli O157 in the period June-September as at other times. However, it must be pointed out that concentrations of E. coli O157 were not calculated.…”

“…The main reservoir of E. coli O157 is considered to be ruminants and in particular cattle which have a highest prevalence in the United States during the warmer summer months [3] and which has been used to partly explain increased human infection at this time [4]. In Scotland however, prevalence studies [5] in beef suckler cattle destined for food have shown that herd level prevalence is greatest in animals that are housed (i.e.…”

Attribution of Human VTEC O157 Infection from Meat Products: A Quantitative Risk Assessment Approach

“…The duration of the lag phase (LPD) is the time that elapses before the bacteria start to grow and is calculated by Ebel et al . : ( 3 ) where a = 9.998, and b =−2.69. ( 32 )…”

“…Last, the maximum population density (MPD) is the maximum number of VTEC O157 present in a product and is given by: where TMD = Triangular (5, Uniform (5,10),10) ( 3 ) is the theoretical maximum density (the maximum VTEC O157 growth achievable in a product) and f =−0.014. ( 32 )…”

“…Risk assessment is a transparent and logical approach for assessing the risk of an unwanted outcome and has been used in the field of food safety by governments, in particular, over the last 10 years. This is highlighted by the numerous risk assessment models for VTEC O157, in particular, currently available from a range of countries including the United States, ( 3 ) the Netherlands, ( 4 ) Canada, ( 5 ) Australia, ( 6 ) and the Republic of Ireland. ( 7,8 ) All of these models have focused on beef mince, which is considered to be the primary product associated with human food‐borne infection.…”