Non-starter bacterial communities in aged Cheddar cheese: Patterns on two timescales

2021 ◽  
Author(s):  
Jared Johnson ◽  
Brandon Selover ◽  
Chris Curtin ◽  
Joy Waite-Cusic
Keyword(s):  
Microbial Contamination ◽  
Starter Culture ◽  
Temporal Stability ◽  
Cheddar Cheese ◽  
Time Of Day ◽  
Sequence Variants ◽  
Microbial Composition ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Contact Surfaces

The aim of this study was to investigate the temporal stability of microbial contamination during Cheddar cheese production by examining patterns of non-starter bacteria in 60-day aged Cheddar collected from the start and end of 30 consecutive production days. Further, we explored the source of these temporal microbial variations by comparing microbial communities in the aged cheese to those on food contact surfaces from a piece of cheesemaking equipment previously identified as a major source of non-starter bacteria in the same processing environment. 16S rRNA metabarcoding and culture-based sequencing methods identified two Streptococcus sequence variants significantly associated with the end of the production day in both the aged cheese and the cheese processing environment. Closer inspection of these sequence variants in the aged cheese over the 40-day sampling period revealed sinusoidal-like fluctuations in their relative ratios, which appeared to coincide with the Lactococcus starter rotation schedule. These results demonstrate that the microbial composition of finished cheese can vary according to the timing of processing within a production day. Further, our results demonstrate that time-of-day microbial differences in cheese can result from bacterial growth on food contact surfaces and that the composition of these microbial differences is subject to change day-to-day and may be linked to routine changes in the Lactococcus starter culture. Importance. Long production schedules used in modern cheese manufacturing can create circumstances which support the growth of microorganisms in the cheese processing environment. This work demonstrates that this growth can lead to significant changes in the microbial quality of aged cheese produced later in the production day. Further, we demonstrate that the dominant bacteria associated with these microbial changes throughout production are subject to change between days and might be influenced by specific cheese manufacturing practices. These findings improve understanding of microbial contamination patterns in modern food manufacturing facilities, therefore improving our ability to develop strategies to minimize quality losses due to microbial spoilage.

scholarly journals The Cheese Production Facility Microbiome Exhibits Temporal and Spatial Variability

2021 ◽  
Vol 12 ◽  
Author(s):  
Jared Johnson ◽  
Chris Curtin ◽  
Joy Waite-Cusic
Keyword(s):  
Product Quality ◽  
Cheddar Cheese ◽  
Starter Cultures ◽  
Growth Media ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Repeated Sampling ◽  
Conveyor Belts ◽  
Contact Surfaces ◽  
Cheese Production

A primary goal of modern cheese manufacturing is consistent product quality. One aspect of product quality that remains poorly understood is the variability of microbial subpopulations due to temporal or facility changes within cheese production environments. Therefore, our aim was to quantify this variability by measuring day-day and facility-facility changes in the cheese facility microbiome. In-process product (i.e., milk and cheese) and food-contact surfaces were sampled over the course of three production days at three cheese manufacturing facilities. Microbial communities were characterized using 16S rRNA metabarcoding and by plating on selective growth media. Each facility produced near-identical Cheddar cheese recipes on near-identical processing equipment during the time of sampling. Each facility also used a common pool of Lactococcus starter cultures which were rotated daily as groups of 4–5 strains and selected independently at each facility. Diversity analysis revealed significant facility-facility and day-day differences at each sample location. Facility differences were greatest on the food contact surfaces (i.e., draining-matting conveyor belts), explaining between 25 and 41% of the variance. Conversely, daily differences within each facility explained a greater proportion of the variance in the milk (20% vs. 12%) and cheese (29% vs. 20%). Further investigation into the sources of these differences revealed the involvement of several industrially relevant bacteria, including lactobacilli, which play a central role in flavor and texture development during Cheddar cheese ripening. Additionally, Streptococcus was found to contribute notably to differences observed in milk samples, whereas Acinetobacter, Streptococcus, Lactococcus, Exiguobacterium, and Enterobacteriaceae contributed notably to differences on the food contact surfaces. Facility differences in the cheese were overwhelmingly attributed to the rotation of Lactococcus starter cultures, thus highlighting circumstances where daily microbial shifts could be misinterpreted and emphasizing the importance of repeated sampling over time. The outcomes of this work highlight the complexity of the cheese facility microbiome and demonstrate daily and facility-facility microbial variations which might impact cheese product quality.

scholarly journals Metagenomic Analysis of Microbial Composition Revealed Cross-Contamination Pathway of Bacteria at a Foodservice Facility

2021 ◽  
Vol 12 ◽  
Author(s):  
Eun Seob Lim ◽  
Jin Ju Kim ◽  
Woo Jun Sul ◽  
Joo-Sung Kim ◽  
Bomin Kim ◽  
...  
Keyword(s):  
Amplicon Sequencing ◽  
Temporal Variations ◽  
Cross Contamination ◽  
Microbial Composition ◽  
Air Contamination ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Food Quality And Safety ◽  
Contact Surfaces ◽  
Contamination Routes

Bacterial contamination of food-contact surfaces can be a potential risk factor for food quality and safety. To evaluate the spatial and temporal variations of the potential cross-contamination routes, we conducted a biogeographical assessment of bacteria in a foodservice facility based on the diversity of microflora on each surface. To this end, we performed high-throughput amplicon sequencing of 13 food-contact and non-food contact surfaces in a foodservice facility throughout a year. The results showed that Bacillus, Acinetobacter, Streptophyta, Enterobacter, Pseudomonas, Serratia, Enhydrobacter, Staphylococcus, Paracoccus, and Lysinibacillus were the dominant genera found on the kitchen surfaces of the foodservice facility. Depending on the season, changes in Firmicute/Proteobacteria ratios were observed, and the fan becomes the main source of outdoor air contamination. The microbial flow associated with spoilage was also observed throughout food preparation. Taken together, our results would be a powerful reference to hygiene managers for improvement of food processes.

scholarly journals Microbiological Analysis of Food Contact Surfaces in Child Care Centers

2008 ◽  
Vol 74 (22) ◽  
pp. 6918-6922 ◽  
Author(s):  
Catherine M. Cosby ◽  
C. A. Costello ◽  
W. C. Morris ◽  
B. Haughton ◽  
M. J. Devereaux ◽  
...  
Keyword(s):  
Child Care ◽  
Care Center ◽  
Microbiological Quality ◽  
Time Of Day ◽  
Microbiological Analysis ◽  
Child Care Centers ◽  
Survey Period ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Contact Surfaces

ABSTRACT A study of six child care centers was conducted to assess the microbiological quality of three food contact surfaces (one food serving surface and two food preparation surfaces) and one non-food contact surface (diaper changing surface) to determine the effectiveness of cleaning and sanitization procedures within the facilities. Aerobic plate counts (APCs) and Escherichia coli/coliform counts of 50-cm2 areas on all surfaces were determined using standard microbiological swabbing methods. Samples were taken three times a day (preopening, lunchtime, and following final cleanup) twice per month for 8 months in each child care center (n = 288 sampling times). Mean log APCs over the survey period were 1.32, 1.71, 1.34, 1.96, 1.50, and 1.81 log CFU/50 cm2 for the six centers. Mean log coliform counts were 0.15, 0.40, 0.33, 1.41, 0.28, and 1.12 CFU/50 cm2 for the same centers. Coliforms were detected in 283 of 1,149 (24.7%) samples, with counts ranging from 1 to 2,000 CFU/50 cm2, while E. coli was detected in 18 of 1,149 (1.6%) samples, with counts ranging from 1 to 35 CFU/50 cm2. The findings of this study demonstrated that the extent of bacterial contamination was dependent on the center, time of day, and the area sampled. While no direct correlation between contamination and illness can be made, given the high risk of food-borne illness associated with children, microbial contamination of food contact or non-food contact surfaces is an aspect of food safety that requires more attention. Emphasis on training and the development of modified standard sanitation operating procedures for child care centers are needed to reduce potential hazards.

A Survey of Microbial Contamination of Food Contact Surfaces at Broiler Slaughter Plants in Taiwan

2004 ◽  
Vol 67 (12) ◽  
pp. 2809-2811 ◽  
Author(s):  
C. P. HO ◽  
N. Y. HUANG ◽  
B. J. CHEN
Keyword(s):  
Microbial Contamination ◽  
Processing Plant ◽  
Hand Tools ◽  
Bacterial Counts ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Cleaning Procedures ◽  
Contact Surfaces ◽  
Contamination Levels ◽  
Bacterial Type

Microbial contamination levels at broiler slaughter plants were investigated at three major slaughter plants in Taiwan during the summer and winter. The microbial contamination levels in chicken carcasses and on food contact surfaces were examined using the swab method. The results indicated that the bacterial counts were affected by the slaughter processing plant, processes, and season (P < 0.05). The bacterial counts on food contact surfaces of the equipment before operation were not significantly lower than those after processing. Regardless of the bacterial type, bacterial counts of chicken carcasses generally decreased from the scalding step to the washing step before evisceration and then increased. The cleaning procedures for food contact surfaces should be evaluated, and special attention should be given to utensils used during processing, such as gloves, baskets, and hand tools.

scholarly journals Genetic Listeria monocytogenes Types in the Pork Processing Plant Environment: From Occasional Introduction to Plausible Persistence in Harborage Sites

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 717
Author(s):  
Niels Demaître ◽  
Geertrui Rasschaert ◽  
Lieven De Zutter ◽  
Annemie Geeraerd ◽  
Koen De Reu
Keyword(s):  
Genetic Diversity ◽  
Environmental Samples ◽  
Genetic Characterization ◽  
Processing Plant ◽  
Pfge Analysis ◽  
Food Contact ◽  
Plant Environment ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Cleaning And Disinfection

The purpose of this study was to investigate the L. monocytogenes occurrence and genetic diversity in three Belgian pork cutting plants. We specifically aim to identify harborage sites and niche locations where this pathogen might occur. A total of 868 samples were taken from a large diversity of food and non-food contact surfaces after cleaning and disinfection (C&D) and during processing. A total of 13% (110/868) of environmental samples tested positive for L. monocytogenes. When looking in more detail, zone 3 non-food contact surfaces were contaminated more often (26%; 72/278) at typical harborage sites, such as floors, drains, and cleaning materials. Food contact surfaces (zone 1) were less frequently contaminated (6%; 25/436), also after C&D. PFGE analysis exhibited low genetic heterogeneity, revealing 11 assigned clonal complexes (CC), four of which (CC8, CC9, CC31, and CC121) were predominant and widespread. Our data suggest (i) the occasional introduction and repeated contamination and/or (ii) the establishment of some persistent meat-adapted clones in all cutting plants. Further, we highlight the importance of well-designed extensive sampling programs combined with genetic characterization to help these facilities take corrective actions to prevent transfer of this pathogen from the environment to the meat.

scholarly journals UV-C LED Irradiation Reduces Salmonella on Chicken and Food Contact Surfaces

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1459
Author(s):  
Alexandra Calle ◽  
Mariana Fernandez ◽  
Brayan Montoya ◽  
Marcelo Schmidt ◽  
Jonathan Thompson
Keyword(s):  
Light Emitting Diode ◽  
Chicken Breast ◽  
Light Emitting ◽  
Work Surface ◽  
Food Contact ◽  
Bacterial Aggregation ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Uv C ◽  
Surface Pores

Ultraviolet (UV-C) light-emitting diode (LED) light at a wavelength of 250–280 nm was used to disinfect skinless chicken breast (CB), stainless steel (SS) and high-density polyethylene (HD) inoculated with Salmonella enterica. Irradiances of 2 mW/cm2 (50%) or 4 mW/cm2 (100%) were used to treat samples at different exposure times. Chicken samples had the lowest Salmonella reduction with 1.02 and 1.78 Log CFU/cm2 (p ≤ 0.05) after 60 and 900 s, respectively at 50% irradiance. Higher reductions on CB were obtained with 100% illumination after 900 s (>3.0 Log CFU/cm2). Salmonella on SS was reduced by 1.97 and 3.48 Log CFU/cm2 after 60 s of treatment with 50% and 100% irradiance, respectively. HD showed a lower decrease of Salmonella, but still statistically significant (p ≤ 0.05), with 1.25 and 1.77 Log CFU/cm2 destruction for 50 and 100% irradiance after 60 s, respectively. Longer exposure times of HD to UV-C yielded up to 99.999% (5.0 Log CFU/cm2) reduction of Salmonella with both irradiance levels. While UV-C LED treatment was found effective to control Salmonella on chicken and food contact surfaces, we propose three mechanisms contributing to reduced efficacy of disinfection: bacterial aggregation, harboring in food and work surface pores and light absorption by fluids associated with CB.

Efficacy of saturated steam against Listeria innocua biofilm on common food-contact surfaces

Food Control ◽  
2021 ◽  
Vol 125 ◽  
pp. 107988
Author(s):  
Zi Hua ◽  
Frank Younce ◽  
Juming Tang ◽  
Dojin Ryu ◽  
Barbara Rasco ◽  
...  
Keyword(s):  
Listeria Innocua ◽  
Saturated Steam ◽  
Food Contact ◽  
Common Food ◽  
Food Contact Surfaces ◽  
Contact Surfaces
Sign in / Sign up

Export Citation Format

Share Document