Validation of Good Agricultural Practices (GAP) on Minnesota Vegetable Farms

Prevalence and molecular characterization of Salmonella isolated from wild birds in fresh produce environments

Wild birds pose a difficult food safety risk to manage because they can avoid traditional wildlife mitigation strategies, such as fences. Birds often use agricultural fields and structures as foraging and nesting areas, which can lead to defecation on crops and subsequent transfer of foodborne pathogens. To assess the food safety risk associated with these events, wild bird feces were collected from produce fields across the southeastern United States during the 2021 and 2022 growing seasons. In total 773 fecal samples were collected from 45 farms across Florida, Georgia, South Carolina, and Tennessee, and 2.1% (n = 16) of samples were Salmonella-positive. Importantly, 75% of Salmonella were isolated from moist feces, showing reduced Salmonella viability when feces dry out. 16S microbiome analysis showed that presence of culturable Salmonella in moist feces correlated to a higher proportion of the Enterobacteriaceae family. From the Salmonella-positive samples, 62.5% (10/16) contained multi-serovar Salmonella populations. Overall, 13 serovars were detected, including six most commonly attributed to human illness (Enteriditis, Newport, Typhimurium, Infantis, Saintpaul, and Muenchen). PCR screening identified an additional 59 Salmonella-positive fecal samples, which were distributed across moist (n = 44) and dried feces (n = 15). On-farm point counts and molecular identification from fecal samples identified 57 bird species, including for 10 Salmonella-positive fecal samples. Overall, there was a low prevalence of Salmonella in fecal samples, especially in dried feces, and we found no evidence of Salmonella transmission to proximal foliage or produce. Fecal samples collected in farms close together shared highly related isolates by whole genome sequencing and also had highly similar Salmonella populations with comparable relative frequencies of the same serovars, suggesting the birds acquired Salmonella from a common source.

Produce Growers' On-Farm Food Safety Education: A Review

ABSTRACT

From planting to distribution, fresh produce can be contaminated by humans, water, animals, soil, equipment, and the environment. Produce growers play an essential role in managing and minimizing on-farm food safety risks. Because of an increase in public awareness about produce safety, farmer food safety education has become an important research and extension topic. This review article summarizes findings by researchers who have evaluated produce growers' food safety knowledge and attitudes and the effectiveness of food safety educational programs for growers. A search of on-line databases, journal archives, conference abstracts, and reference lists of relevant studies was conducted to locate peer-reviewed articles on produce growers' food safety knowledge and behavioral changes. Study selection criteria included publications in English, publication between 2000 and 2019, and a focus on one of six topics: handling of agricultural water, soil amendments, domesticated animal and wildlife management, worker health and hygiene, food safety plans and record-keeping, and cleaning and sanitation. Forty-three published articles were included in the analysis. Handling of agricultural water and soil amendments were the two topics least understood by growers, whereas worker health and hygiene were the best understood. Food safety educational interventions were evaluated in 13 studies, and most studies used in-person workshops and self-reported pre- and postintervention knowledge assessments. Most reported increased knowledge, some reported improved attitudes and perceived behavioral control, and only four reported behavioral changes. Because of small sample sizes, many studies did not include a statistical analysis of the differences between pre- and postintervention survey results. This review article provides insights and guidance for the development of food safety education for produce growers.

HIGHLIGHTS

Microbiological Parameters in the Primary Production of Berries: A Pilot Study

The primary production of fresh soft fruits was considered to be a suspected critical point for the contamination of frozen berries that were responsible for the large 2013⁻2014 Hepatitis A virus (HAV) outbreak in Europe. In this study, an Italian berries’ production area was studied for its agro-technical characteristics, and the fresh fruits were analyzed for the presence of enteric viruses (HAV and Norovirus (NoV) genogroup I and genogroup II (GGI and GGII)), the enumeration of hygienic quality parameters, and the prevalence of bacterial pathogens. A total of 50 producers were sampled, who specialized in the exclusive or shared cultivation of berries. Escherichia coli was detected in two blackberry samples, whereas HAV and Norovirus were not detected. The samples were negative for Salmonella spp., Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC). The farms’ attributes were not associated with positive samples, apart from the presence of E. coli and the aerobic mesophilic bacteria for blackberry that were statistically correlated. In blueberries, the high aerobic mesophilic count could likely be associated with the resistance of the outer layer to handling. However, the two pathogens (Salmonella spp. and STEC) and the targeted viruses (HAV, NoV GGI and GGII) were not detected, highlighting the low risk of foodborne pathogens and viral contamination at the primary production stage of the berry food chain in the area considered in this pilot study.