*3.5.2 Workers, on-farm activities, and farming equipment and tools*

#### *3.5.2.1 Farm workers*

Authorized or unauthorized human activity, regardless the status, farm worker or trespassers, could take place on the farm premises and on growing fields and could result in the produce contamination with pathogens. However, due to the daily, continuous type of work, the farmers and farm workers are playing an important role in maintaining uncompromised the microbial safety of the fresh produce,

### *Pathogenic* Escherichia coli*: An Overview on Pre-Harvest Factors That Impact the Microbial… DOI: http://dx.doi.org/10.5772/intechopen.101552*

leafy greens, respectively, while performing their duties. A survey of Midwestern United States farms brought up an important aspect: while the most farmers were familiar with GAPs, the GAPs were not fully implemented on farms because they did not believe that the fresh produce contamination with pathogens were the direct result of their on-farm practices and there are several factors which farmers view as obstacles in GAPs implementation (**Table 9**) [139, 140].

Also, multiple studies indicated that the workers' clothing, hands, feet, and training are involved in fresh produce contamination with pathogens [141–143]. The survey data obtained by Antwi-Agyei *et al.* supports the fact that on-farm workers' hygiene practices could favor the on-field produce contamination with pathogen via hands- and feet-to-soil contact: (a) 73% of workers are practicing open field defecation, while only 25% use a public toilet, and 2.4% other toilets; (b) the percentage of farmers' prior contact to fecal contamination was 69 (as hand-to-soil contact) and 74 (as feet-to-soil contact) [144]. In this context, the data from **Table 7** correlates with other findings related to farm workers hygiene and on-field activities, and, more important with the willingness and the ability of farmers to provide proper conditions for avoiding fresh produce contamination by field workers. Practically, the hygiene interventions specifically designed for produce farm workers and workers' hygiene behavior is affected by farmers on-site policies and offered food safety training. Surveys performed by Bartz *et al.*, Antwi-Agyei *et al.*, and Fabiszewski *et al.* support the fact that the farm workers' hands are the main contamination vehicle of leafy greens during pre-harvest activities, such as: bed preparation, transplanting, soil tilling, weed removal, irrigation, due to the lack of field workers' accessibility of toilets, handwashing posts, eating and resting posts, training, and facilitative work policies to encourage workers to respect and practice the on-field hygiene [141, 142, 144, 145]. According to common guide issued in 1998 by FDA in collaboration with U.S. Department of Agriculture (USDA) and CDC, both farmers and workers must be reminded: (a) that anything that comes in contact with fresh produce has the potential of contaminating it and, for most foodborne pathogens associated with the fresh produce, the major source of contamination is human or animal feces, and (b) worker hygiene and sanitation practices during production, harvesting, sorting, packing, and transportation play a critical role in minimizing the potential for microbial contamination of fresh produce [146]. The multiple survey-based research on farm management and on farm workers indicate several mitigation strategies that could be implemented concomitantly (**Table 10**).


**Table 9.**

*Examples of factors that farmers consider obstacles in implementing GAPsa on their farms\*,a .*


#### **Table 10.**

*Examples of mitigation strategies for being applied concomitantly for ensuring on-farm food safety during pre-harvest stage.*

#### *3.5.2.2 Farming equipment and tools*

Farming is labor intensive and require a variety of working equipment and tools for land preparation (i.e., primary and secondar tilling, primary and secondary applications of manure/fertilizers or pesticides and insecticides, sowing the seeds or transplanting the seedlings, folding, irrigation etc.) and management, manure management, and workers protective equipment. Focusing on the pre-harvest phase of the farm-to-fork chain, the manipulation of leafy greens in the field is of particular concern due the risk of cross-contamination of the produce from unsanitary, soiled farm equipment. Little or no cleaning and sanitation between activities, lack of equipment and tools segregation, and lack of proper storage represent major causes of concern since these can become a direct source of produce contamination with pathogens [66, 93, 148]. In addition, processing of produce in the field such manual practices, and mechanical activities should be performed in ways that reduce the contamination of produce from soil, workers, or equipment surfaces [66]. Since on-farm surveys indicated that some farms do not clean and sanitize properly their equipment, or the equipment was most commonly cleaned by using only water without applying detergents and sanitizers. However, if water alone is used for cleaning the equipment and tools, famers should use only water with high microbiological quality (comparable with drinking water). Several management strategies (standard operation procedures and good hygiene practices, good agricultural practices) were designed to assist farmers and farm workers to reduce the microbial hazard and the microbial cross-contamination between equipment and tools and the fresh produce (**Table 11**) [149–151].

### **4. Conclusions**

A better understanding of the pathogens' behavior in pre-harvest environments will support the developing of effective on-farm food safety management strategies (GAPs, HACCP) and interventions that will ensure the delivery of a safe produce to the consumer. Leafy greens should be given a high food safety priority since they are an important vehicle for pathogenic *E. coli* and are playing an important role in the emergence of new foodborne outbreaks. There are many possible sources of contamination of leafy greens due to their exposure to many different environmental factors, and multiple handling phases until reaching the consumers. Moreover,

*Pathogenic* Escherichia coli*: An Overview on Pre-Harvest Factors That Impact the Microbial… DOI: http://dx.doi.org/10.5772/intechopen.101552*


#### **Table 11.**

*Examples of on-farm cleaning and sanitation procedures for equipment and tools.*

pathogenic *E. coli* could survive in leafy greens for commercially relevant periods even multiple disinfection procedures are applied. Therefore, pre-harvest stage must be viewed and approached as an important process which favors the contamination with pathogenic *E. coli*. The improvement of leafy greens microbial safety can be achieved by embracing the farming management strategies which will help growers to re-examine their own farming processes for reducing or eliminating the food safety risks. Comprehensive surveys, risk assessments, and scientific research on pre-harvest factors are needed to continue to identify risks, mitigation priorities, and the efficacy of different intervention strategies. Because of the frequent growers' failure to implement food safety rules and guidelines on their production premises, the existing mitigation strategies are not a "silver bullet" for minimizing the risk of leafy greens pathogen contamination. Therefore, both regulators and researchers should use the existing and the new incoming information for proposing and continuously designing potential mitigation strategies to be implemented by farmers for reducing the risk of leafy greens contamination with pathogenic *Escherichia coli* to harmless levels. These mitigation strategies have to undergo changes and be re-designed to address newly identified and reported on-farm deviations or violations of the food safety guidelines or of the Good Agricultural Practices (GAPs). Accordingly, the farmers and farm managers should be persuaded and helped to undergo more training sessions. National and international organizations and agencies, and researchers must support farmers to maximize their understanding and adherence to food safety guidelines for increasing their awareness on their role in the assurance of food safety throughout the leafy greens *farm-to-fork* continuum.

Escherichia coli *- Old and New Insights*
