The increasing number of diversified small-scale farms (DSSF) that raise outdoor-based livestock in the US reflects growing consumer demand for sustainably-produced food. Diversified farms are small-scale and raise a combination of multiple livestock species and numerous produce varieties.
This 2015-2016 cross-sectional study aimed to describe the unique characteristics of DSSF in California, estimate the prevalence of STEC in livestock and evaluate the association between risk factors and the presence of STEC in livestock, using generalized linear mixed models. STEC prevalence was 13.62% (76/558). Significant variables in the mixed effect logistic regression model included daily maximum temperature (OR = 0.95; CI95%: 0.91-0.98), livestock sample source (cattle (OR = 4.61; CI95%: 1.64-12.96) and sheep (OR = 5.29; CI95%: 1.80-15.51)), multiple species sharing the same barn (OR = 6.23; CI95%: 1.84-21.15) and livestock having contact with wild areas (OR = 3.63; CI95%: 1.37-9.62).
Identification of STEC serogroups of public health concern (e.g., O157:H7, O26, O103) in this study indicated the need for mitigation strategies to ensure food safety by evaluating risk factors and management practices that contribute to the spread and prevalence of foodborne pathogens in a pre-harvest environment on DSSF.