Identification of microbial hazards, methods for their control and critical control points for black pudding (‘boudin noir’)

Abstract

Hazard analyses of black pudding (`boudin noir') preparation practices were conducted in four operations at an abattoir in Trinidad. The analyses consisted of watching all steps of preparation of the product on three occasions by each of the four processors, taking samples of ingredients and mixtures used during the steps to culture for common food pathogens, taking swab samples of chopping boards used for celery, pepper, onions and garlic, recording the sequential temperatures of water used for heating the stuffed intestine and the internal temperature of the stuffed intestine. A general build up of aerobic mesophilic bacteria was observed on addition of various ingredients like spices, celery, pepper, onions, garlic, fat, bread and blood before stuffing the intestine with a semi-solid mixture. The mean total aerobic plate count was 8.8×10 8±2.7×10 9and 8.5×10 5±1.3×10 6g −1for pre-heated and post-heated stuffed intestine, respectively. Preheated samples yielded Escherichia coli(89.0%), Staphylococcus aureus(99.0%) and Salmonella(14.6%). The mean temperatures of water used in heat processing ranged from 81.0±3.5 to 87.0±8.0°C, the mean internal temperature of stuffed intestine during processing ranged from 63.2±2.8 to 72.6±2.5°C and the mean processing time ranged from 17.3±10.2 to 26.7±4.2min between processors. The temperature treatments employed by the processors were lower than the 85°C for 10–15min recommended for the product. Consequently, the temperature exposure achieved between a 1–4log decrease in the counts aerobic mesophilic bacteria per gram. Of the 22 ready-to-consume black pudding samples tested, 15 (68.2%), 19 (86.4%) and 3 (13.6%) were positive for E. coli, S. aureusand Salmonella, respectively. Hazards were primarily associated with the keeping of blood at ambient temperature for several hours before use, insanitary practices and keeping processed black pudding at ambient temperature. Critical control points were cooking or heat processing, handling of the product after cooking and holding processed black pudding.