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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Residue Chemistry and Predictive Microbiology Research » Research » Publications at this Location » Publication #376086

Research Project: Integration of Multiple Interventions to Enhance Microbial Safety, Quality, and Shelf-life of Foods

Location: Residue Chemistry and Predictive Microbiology Research

Title: Food safety issues and mitigation of prosopis flour

item FELKER, PETER - Casa De Mesquite Llc
item Fan, Xuetong

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/20/2021
Publication Date: 12/16/2021
Citation: Felker, P., Fan, X. 2021. Food safety issues and mitigation of prosopis flour. Book Chapter.

Interpretive Summary:

Technical Abstract: Aflatoxins have been reported on Prosopis pods collected in the wild in Arizona that experiences summer rainfall, which could maintain sufficient moisture levels to allow the Aspergillus fungus to propagate. One lot of Prosopis flour from Peru was found to have 25 ppb which is slightly over the FDA 20 ppb limit. The rod-shaped Bacillus cereus that can produce toxins causing diarrhea and/or vomiting brought on an FDA recall of Prosopis flour in 2012. The Indian meal moth (Plodia interpunctella) that is unsightly but is not a significant human health hazard, often infects Prosopis flour in storage as it does for many common kitchen flours. The Bruchid seed weevil (Algarobius prosopis) burrows into Prosopis pods, consuming the seeds in the seed endocarp for various parts of its life cycle. Bruchids continuously propagate in stored pods until all seeds are consumed. As spores of the Aspergillus fungus and Bacillus cereus are known to propagate in insect intestinal tracts increasing toxin concentrations, it is important to mitigate damage by the bruchid insect as soon as possible. The bruchid insects can be killed by aluminum phosphide fumigants or by subjecting the pods to temperatures greater than 52°C for more than an hour in a mini plastic greenhouse. Irradiation of Prosopis flour with 6 kGy gamma rays reduced the population of Bacillus from 3.4-5.4 log CFU/g to non-detectable levels (detection limit 1 log CFU/g). An FDA petition to use gamma irradiation at a dose of 6 kGy is awaiting results on the effect of irradiation on soluble and non-soluble fibers in Prosopis flour. A 28-second treatment of the flour with intense pulsed light combined with TiO2 beads reduced the Bacillus population by 1.69 log CFU/g. To reduce the populations of Bacillus in the flour by 90% with dry heat, thermal treatment (55 min at 100°C or 27 min at 110°C) may be applied. All mitigation techniques may be useful in decreasing frequently unpermitted, high B. cereus populations in the 10,000 to 90,000 CFU/g range to less than the 10,000 CFU/g permitted range.