Do Temperature Abuses Along the Frozen Açaí Pulp Value Chain Increase Microbial Hazards?

Does temperature abuse during storage, distribution, marketing, and consumption of unpasteurized frozen açaí pulp increase microbial hazards? This study investigated the behavior of potentially pathogenic (Escherichia coli, Listeria monocytogenes and Salmonella spp.) and spoilage (mesophilic bacteria, yeasts and molds) microorganisms in two simulated thawing conditions: under refrigeration and at room temperature. The effect of repeated cold chain abuse was observed by thawing and refreezing (-20°C) açaí pulp four times over a period of 90 days. Freezing resulted in inhibition of all microorganisms except for mesophilic aerobic bacteria in one single sample. After thawing at 5°C, the kinetic parameters obtained by the Weibull model indicated that mesophilic aerobic bacteria, yeasts and molds and L. monocytogenes showed a longer inactivation time with δ values reaching 35, 126, and 46 days, respectively. The shortest inactivation time for a reduction of 4 log CFU.g^-1 was for E. coli. The concentration of Salmonella spp. and L. monocytogenes in control samples was higher (p < 0.01) than in samples exposed to abusive conditions after 90 days of storage. The results indicate that the abusive thawing conditions studied do not increase the potential hazards of pathogens.