Microbiological, physical and chemical quality of water used in artisanal dairy factories from Tandil, Argentina

Dairy production requires an abundant good-quality water supply. This research aimed to study water quality in eight artisanal dairies from Tandil, Buenos Aires province, Argentina, which use groundwater resource. Data were collected and water samples were taken in different visits from 2016 to 2020. The analysis showed that 41% of the samples obtained from the perforations did not meet the physical and chemical criteria established by the Argentine Food Code for drinking water, mainly due to excess salts such as nitrates or salts that cause hardness, and 41 % were not suitable according to microbiological criteria, mainly due to a high total coliform count (TC). Likewise, high TC counts and the presence of Escherichia coli and Pseudomonas aeruginosa were evidenced in water samples obtained from dairy farms (54 % CT, 19 % E. coli and 12 % P. aeruginosa) and factories (33% CT, 7% E. coli and 2% P. aeruginosa). Sulfite-reducing clostridia, enterococci, and Salmonella spp. were also detected in some samples. Despite the good quality of the aquifer in the region, these results evidenced sites with point contamination, which could be related to the infiltration of the discharged effluents and the disposal of excreta in the vicinity of the wells. The use of water with microbiological and/or physical and chemical quality problems in these establishments can negatively affect the quality of the products and constitute a risk to the health of consumers.