Use of Alternative Sanitizers on Minimally Processed Watercress Harvested in Two Different Seasons

Abstract

There is an increasing concern about the formation of halogenated compounds when sodium hypochlorite (SH) is used as food sanitizer. This research evaluated the quality of watercress harvested in two seasons treated with alternative sanitizers combined with modified atmosphere packaging. Chlorine dioxide (5–10 mg/L), acidified sodium chlorite (250–500 mg/L), peroxyacetic acid (50–90 mg/L) and SH (100 mg/L) were used. Initial respiration rate decreased from 80–135 to 40–72 mg CO2 kg/h in spring- and summer-harvested watercress. Chlorine dioxide and SH caused a reduction in aerobic mesophilic bacteria of 1.8 and 1.3 log colony-forming unit (cfu/g), respectively. Enterobacteriaceae reductions of 1.1 log cfu/g were achieved using SH and peroxyacetic acid in spring and 1.4 log cfu/g by applying acidified sodium chlorite in summer. None of the sanitizers could handle high initial microbial loads for more than 8 days, showing that a raw material with low initial microbial count is required to guarantee the product safety. Practical Applications Nowadays, the food market is challenging an increasing demand for safer products that must be elaborated under strict food and environmental standards. In this sense, the application of nontraditional sanitizers could be an alternative to sodium hypochlorite that is being questioned due to the potential formation of halogenated compounds during sanitation. The use of alternative sanitizers in high doses represents a feasible choice for minimally processed vegetables because this technology does not leave toxic residues in foods and neither requires additional investment on industrial facilities, preserves the sensory attributes of vegetables and helps to improve the microbiological quality of ready-to-eat products.