Table 1.

Stratification of environmental sources, transmission routes and risk factors of AMR –plant‐based food production sector

AMR sources	Plant‐based foods for animal use		Plant‐based foods for human use				Supporting references	Comments
	Field crops					Covered
Primary production	Forage	Feed	Root	Leafy green	Aerialb	Vegetables, fruits and mushrooms
Irrigation water	++	++	++	++	++	+	Christou et al. (2017), Araújo et al. (2017), Gekenidis et al. (2018)	Aerial parts of the plant will be exposed in the case of overhead irrigation.
Animal wastea	++	++	++	++	+	+	Heuer et al. (2011)	Organic greenhouse production may use animal manure as a fertiliser
Human wastea	++	++	++	++	+	–	Bondarczuk et al. (2016)	Mandated delays between sludge application and harvest of crops destined for human consumption will attenuate risk. Situation with forages not as clear.
Workers/visitors	–	–	–	–	–	+	Machado‐Moreira et al. (2019)
Wildlife	?/+	?/+	?/+	?/+	–	–	Swift et al. (2019)
Air	?/+	?/+	?/–	?/+	?/+	?/–	Laube et al. (2014)	Contamination risk dependent on proximity to barns or other sources of airborne emissions
Growth substrate	–	–	–	–	–	+	Dróżdż et al. (2020)	Poultry manure can comprise part of the growth substrate and needs to be composted effectively.
Proximal animal farms	?/+	?/+	?/+	?/+	?/+	?/–	Holvoet et al. (2013)	Likelihood of contamination via runoff following manure application greater when livestock farm is nearby
Biocides	?/+	?/+	?/+	?/+	?/+	?/+	FAO/WHO (2018)	Although biocides could co‐select for AMR, there is an absence of evidence that it occurs in production or processing environments
Heavy metals	+	+	+	+	+	+	Seiler and Berendonk (2012), EFSA FEEDAP Panel (2016), FAO/WHO (2018)	Although heavy metals could co‐select for AMR, there is an absence of evidence that it occurs in commercial production or processing environments. The EFSA FEEDAP Panel recommended ‘implementing a monitoring of copper pollution from agriculture in areas in which food‐producing animals are fed, with particular attention to the potential development of microbial antibiotic resistance in the environment. The data would help to identify any area under risk’.
Harvest and handling	Forage	Feed	Root	Leafy green	Aerial	Vegetables & fruits
Water	?/+	?/+	?/+	?/+	?/+	?/+		No literature available; relative risk based on expert opinion
Humans	?/+	?/+	?/+	?/+	?/+	?/+		No literature available; relative risk based on expert opinion
Wildlife	?/+	?/+	?/+	?/+	?/+	?/‐		No literature available; relative risk based on expert opinion
Machinery, bins, totes	?/‐	?/‐	?/+	?/+	?/+	?/‐		No literature available; relative risk based on expert opinion
Processing	Forage	Feed	Root	Leafy green	Aerial	Vegetables & fruits
Water	?/+	?/+	?/+	?/+	?/+	?/+		No literature available; relative risk based on expert opinion
Humans	?/+	?/+	?/+	?/+	?/+	?/+		No literature available; relative risk based on expert opinion
Seed sprouting					++		EFSA BIOHAZ Panel (2011b)	Recommendations have been made for safe production, notably by protecting seed quality. These are intended for reducing risk from pathogens, not ARB.

Importance of the single sources is given from – (not important) to + (represents a source/factor of AMR, evidence for introduction existing for other bacteria), to ++ (important source/factor of AMR)). ?: specific information is missing.?/‐ No scientific evidence but presumably no source/factor, ?/+ No scientific evidence but presumably source/factor as AMR is present in the source and introduction to the farm is possible. Importance is assigned based on the presence of supporting references and expert assessment, as scientific evidence on the relative attribution of AMR to the specific environmental sources is generally lacking. Dark gold: environmental sources, red: other selective pressures/risk factors.

^aSources of contamination (e.g. though manure or sludge).

^b‘Aerial’ food products include above ground vegetables, fruits and seeds (e.g. walnuts, olives, tomatoes, apples, etc.).