Water Quality for Farming Use and Food Safety in the Field

Water is the main vehicle to bring pollution to farming products, as it is very easy for pathogen microorganisms to remain present or even reproduce themselves in it. Water is also present in most processes and comes into contact with surfaces such as hands of workers, packaging tables, hauling vehicles and even fruits and vegetables themselves. All of this without ignoring the possibility of water being polluted by any kind of chemicals frequently used in the farming industry itself.

For all of these reasons, it is of utmost importance that during Eleven Rivers’ weekly audits, water becomes a priority subject to be thoroughly reviewed and considers factors such as:

Water quality according to use

Irrigation water (If water comes into contact with the edible part of the crop, it must be management water  quality)

Management water (Various uses, such as: foliar applications, personal hygiene, product washing, contact surface washing, chemicals)

Water for consumption (Intended for drinking and/or ice making)

Applicable regulations for water quality in Mexico:

OFFICIAL MEXICAN STANDARD NOM-001-SEMARNAT-1996, ESTABLISHES THE MAXIMUM PERMISSIBLE LIMITS OF POLLUTANTS IN WASTEWATER DISCHARGES ON DOMESTIC WATERS AND GOODS (irrigation water)

OFFICIAL MEXICAN STANDARD NOM-127-SSA1-1994, “ENVIRONMENTAL HEALTH, WATER FOR HUMAN USE AND CONSUMPTION – PERMISSIBLE LIMITS OF QUALITY AND THE TREATMENTS WATER MUST BE SUBMITTED TO FOR PURIFICATION ” (management water)

OFFICIAL MEXICAN STANDARD NOM-201-SSA1-2002, PRODUCTS AND SERVICES. WATER AND ICE FOR HUMAN CONSUMPTION, PACKED AND IN BULK. HEALTH SPECIFICATIONS. (ice)

Water intended for farming (FSMA):

Water Quality:

The final rule establishes two sets of criteria for microbial quality of water, which are based on the presence of E. coli, and may indicate the presence of fecal contamination.

Detectable generic E. coli are not allowed for certain water uses in farming, where it is reasonably likely that potentially hazardous microbes, if present, will be transferred to the product through direct or indirect contact;

Examples include:

Water used for hand washing during and after harvest,

Water used on surfaces in contact with food,

Water used in direct contact with products (including ice making) during or after harvest, and

Water used to irrigate shoots.

The standard establishes that:

“If generic E. coli is detected, such water use must be immediately suspended and corrective actions should be taken before reusing it for any of these purposes.”

The use of untreated surface waters for any of these purposes is prohibited.

The second set of numerical criteria is for farming use water being applied directly to product crops, the inedible part (except for shoots).

Criteria are based on two values, the geometric mean (GM) and the statistical threshold (STV).GM of samples is equal or less than 126 CFU of generic E. coli per 100 ml of water, andSTV of samples is equal or less than 410 CFU of generic E. coli per 100 ml of water.

GM is an average, and therefore, it represents what is called the central trend in water quality (basically, the average amount of generic E. coli on a source of water).

STV shows the amount of variability in water quality (indicating E. coli levels when adverse conditions get involved, such as rain or a river flooding stage which can wash wastes in rivers and channels). Although this is excessive simplification, it can be described as the level where 90% of samples are below the value.

FDA is studying the development of an online tool farms can use to enter their water sample data and calculate these values.

Measures to ensure water quality:

Inspection