Educational Programming

Microbial Transfer & Cross-Contamination in Milling Facilities

Scott Osborne, Mennel Milling Company; Andreia Bianchini-Huebner, University of Nebraska

Contributors: Jayne Stratton & Aryany Leticia Pena Gomez, University of Nebraska

Microbial contaminants entering the mill with incoming wheat kernels and the accumulation of grain or flour residues within milling equipment present significant risks for cross-contamination during processing. This potential transfer of microorganisms from equipment to food raises serious food safety concerns, often associated with pathogen cross-contamination in food processing environments, a leading cause behind food recalls. When assessing natural levels of microbial contamination, equipment dedicated to cleaning and tempering operations harbors elevated microbial loads, serving as reservoirs for mesophilic bacteria, Enterobacteriaceae, and molds. Moreover, coliform counts significantly increase from wheat kernels to milled fractions, especially in flour handling and storage equipment. To further understand these microbial interactions in the mill, wheat contaminated with non-pathogenic E. coli (~4.5 log CFU/g) was processed. Results of this trial showed higher microbial transfer in non-flour milling fractions (~3.6 log CFU/g). However, significant contamination levels were also observed in straight-grade flour (~2.6 log CFU/g). Additionally, this contamination was reflected on the milling equipment surfaces, showing quantifiable microbial counts (up to 2.3 log CFU/10 cm2). Following the contaminated batch, non-inoculated wheat was sent through the mill as a simulation of wheat that had been treated via pathogen mitigation technologies. The mill ran for a period of time equivalent to two times its capacity, while samples were collected. Additionally, simple cleaning steps were implemented. These steps effectively reduced microbial contamination in flour fractions and equipment (<1 log CFU/g and <1 log CFU/10 cm2) to baseline levels. These data demonstrate that cross-contamination in wheat milling processing can easily occur, transferring microbial contamination from wheat kernels to equipment and fractions and vice versa. Importantly, these same contaminants are also able to be flushed through the system using grains that are free of microbial contamination. These results imply that pathogen mitigation technologies implemented during the tempering step can be an effective tool in producing flour that has significantly reduced microbial contamination, given a proper flush of the mill is carried out initially, without the concern that it will be re-contaminated during the milling process. [/av_iconlist_item] [av_iconlist_item title='Wednesday, April 17 | 1:35-2:05 p.m. ' icon='ue8c1' font='entypo-fontello' heading_tag='' heading_class='' link='' linktarget='' title_attr='' linkelement='' av_uid='av-2g7aq1' sc_version='1.0']

FDA Inspections – What’s Key?

Glenn Bass, FDA

Level-Up Your Foggings and Fumigations

Eric Meyers, ADM

Have you ever wondered why you see insect trails within days of a fogging? Or a quick rebound in pheromone counts and sifter tailings? Would substantial insect fallout be evidence of a successful treatment or an indicator of something else going on? Stored product insects are a unique group that can be challenging to manage effectively and with underperforming sanitation and pest control, they can cause a number of disruptions. Extensive fogging’s and fumigations are a common practice however they should be considered a part of an overall strategy and not routine practice. To achieve the best results, site preparation is key, with cleaning and exposure being the two driving factors. Subsequently, a post treatment inspection can offer great learning opportunities on how to improve MSS, GMP, pest control programs and preparation efforts treatment to treatment.