Category Archives: Coliforms

Research – Microbiological Survey of Wheat Flour Sold at Retail in Canada, 2018-2019

Journal of Food Protection

Following two O121 STEC outbreaks linked to wheat flour, this study was conducted to gain baseline information on the occurrence of bacterial pathogens and levels of indicator organisms in wheat flour in Canada. A total of 347 pre-packaged wheat flour samples were analyzed for Salmonella spp., Shiga Toxin-Producing Escherichia coli (STEC), Listeria monocytogenes ( L. monocytogenes ) , aerobic colony count (ACC), total coliforms, and generic Escherichia coli ( E. coli ) . Salmonella spp. and O157 STEC were not detected in any of the samples. L. monocytogenes was identified in two samples (0.6%) at levels below the limit of detection (<0.7 log CFU/g). Non-O157 STEC were isolated from six samples (1.7%) and were characterized for the presence of STEC virulence genes: stx 1, stx 2 and subtypes, eae , hlyA, and aggR . One O103:H25 STEC isolate carried virulence genes ( stx 1 a + eae ) that are known to be capable of causing diarrhea and/or bloody diarrhea in humans. Of the five remaining non-O157 STEC isolates, four carried single stx 2a or stx 2c genes and were considered to have the potential of causing diarrhea. The remaining non-O157 STEC isolate ( stx 2 ), while not a priority non-O157 STEC was not available for sequencing and thus its potential to cause illness is unknown. ACC, total coliforms, and generic E. coli were detected   in 98.8%, 72.6% and 0.6% of the flour samples. The mean counts of ACC were greater in whole-wheat flour as compared to the other flour types tested ( p <0.001). The results of this study suggest that the occurrence of O157 STEC and Salmonella  is low, but the occurrence of non-O157 STEC in wheat flour with the potential to cause human illness of diarrhea is relatively common. Therefore, the consumption of raw flour could increase the likelihood of STEC infections. Further research is merited for potential risk mitigation strategies within the food production system and with consumers.

RASFF Alert – Coliforms – Natural Mineral Water

European Food Alerts

RASFF

presence of coliforms (7.8 x 10¹ [5.5 x 10¹; 1.1x 10²] /250ml) in natural mineral water from Belarus in Lithuania

Research – Microbiological profile, incidence and behavior of Salmonella on seeds traded in Mexican markets.

Journal of Food Protection

Seed consumption has increased in recent years because the high nutrient content of seeds. However, the number of outbreaks caused by Salmonella associated with the consumption of low water activity food items has also increased, although these food items do not support microbial growth. The main goal of this study was to quantify microbial indicators and to determine the prevalence and content of Salmonella spp. in chia, amaranth and sesame seeds obtained from Mexican retail outlets. In addition, the behavior of this pathogen on seeds was also evaluated. One hundred samples of each product (chia, amaranth and sesame seeds) were collected from Queretaro City markets. Aerobic plate count (APC), coliforms and Escherichia coli were quantified, and the presence and number of Salmonella were also determined. Chia, amaranth and sesame seeds (1 kg each) were inoculated with a cocktail containing five Salmonella strains (~6 log CFU mL -1 ) and were stored at ambient temperature and populations of Salmonella were quantified. The median APC contents in chia, amaranth, and sesame seeds were 2.1, 2.4, and 3.8 log CFU g -1 , respectively, and the content of coliforms on the seeds ranged from 0.48 to 0.56 log MPN g -1 . E. coli was present at low concentrations in the three types of seeds. Salmonella was detected in chia (31%), amaranth (15%), and sesame (12%) seeds, and the population ranged from 0.48 to 0.56 Log MPN g -1 . Salmonella spp. decreased through 240 days of storage, showing inactivation rates of 0.017, 0.011 and 0.016 log CFU h -1 in chia, amaranth, and sesame seeds, respectively. The high prevalence of Salmonella in the seeds highlights potential risks for consumers, particularly giving that seeds are generally consumed without treatments guaranteeing pathogen inactivation.

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s ( < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss ( < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

Research – Presence of Bacterial Pathogens and Levels of Indicator Bacteria Associated with Duck Carcasses in a Commercial Processing Facility

Journal of Food Protection

ABSTRACT

Little information has been published on the microbiological aspects of U.S. commercial duck processing. The objective of this study was to measure prevalence and/or levels of bacteria in duck samples representing the live bird and partially or fully processed oven-ready duck meat. At 12 monthly sampling times, samples were collected at six sites along the processing line in a commercial duck slaughter plant. Crop and cecum samples were collected at the point of evisceration. Whole carcass rinse samples were collected before and after carcass immersion chilling plus application of an antimicrobial spray. Leg quarters were collected from the cut-up line before and after application of an antimicrobial dip treatment. All samples (five from each site per monthly replication) were directly plated and/or enriched for Salmonella and Campylobacter. For the last 10 replications, carcass and leg quarter rinse samples were also evaluated for enumeration of total aerobic bacteria, Escherichia coli, and coliforms. Most cecum, crop, and prechill carcass rinse samples were positive for Campylobacter (80, 72, and 67%, respectively). Carcass chilling and chlorinated spray significantly lowered Campylobacter prevalence (P < 0.01), and even fewer leg quarters were positive for Campylobacter (P < 0.01). Passage through a chlorinated dip did not further reduce Campylobacter prevalence on leg quarters. Salmonella was infrequently found in any of the samples examined (≤10%). Total aerobic bacteria, coliforms, and E. coli levels were reduced (P < 0.01) on whole carcasses by chilling but were not different after cut-up or leg quarter dip treatment. Overall, current commercial duck processing techniques as applied in the tested plant were effective for reducing the prevalence and levels of Campylobacter on duck meat products.

HIGHLIGHTS
  • Campylobacter and Salmonella can be associated with live ducks for commercial slaughter.
  • Antimicrobial treatment reduced the prevalence of Campylobacter in duck samples.
  • Antimicrobial treatment reduced levels of aerobic bacteria, coliforms, and E. coli in duck samples.

Research – Scale‐up model of forced air‐integrated gaseous chlorine dioxide for the decontamination of lowbush blueberries

Wiley Online 

Gaseous chlorine dioxide (ClO2) is a promising sanitizer for frozen products because of its efficacy under nonthermal and waterless conditions. A major knowledge gap exists between laboratory trials and effectiveness at the industrial scale. To address this, a pilot study implementing a pallet‐sized fumigation container (60 harvest totes) was designed for gaseous ClO2. Fifty kilograms of blueberries were exposed to initial dose of 57.46 mg/L, representing a treatment of 2.35 mg/g of blueberries. Blueberries remained enclosed for 10 hr. Reduction of all viable cells, coliforms, yeasts, and molds were measured by plating treated samples on Tryptic Soy Agar, Violet Red Bile Agar, and Dichloran Rose Bengal Chloramphenicol Agar and compared to untreated controls. The results demonstrate that a significant reduction of 1.5 log CFU/g can be achieved against coliforms after ClO2 exposure. Our findings demonstrate a cost‐effective procedure that could be adapted to commercial processing.

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s (p < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss (p < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

Research – Microbiological and parasitological contamination of vegetables, water and soil in rural communities

AJOM

Microbiological and parasitological contamination of vegetables, water and soil in rural communities of a municipality in the state of Bahia, Brazil, was assessed. Samples of Lactuca sativa, L., Coriandrum sativum and Solanum lycopersicum, soil, and irrigation water were analyzed between August and October, 2015. Total coliforms (TC), Escherichia coli, molds and yeasts on vegetables, soil and water, heterotrophic bacteria in water and soil were counted. Parasitological analyses were performed by spontaneous sedimentation method and by Rugai technique for vegetables and soil and by direct and Faust exams for water. Physical and chemical analyses included pH, temperature, dissolved oxygen and turbidity. TC counts were higher in lettuce samples (mean 2.8 log CFU g-1). E. coli counts did not comply with legislation in a lettuce sample with 3.3 log CFU g-1. TC had the highest counts, with mean between 3.7 and 4.9 log CFU g-1 in soil samples. All water samples showed poor conditions and most samples were positive for at least one parasite. Due to high microbial density and several parasite types in most samples, results showed poor sanitary quality of vegetables with health risks for people. It is crucial to invest in educational activities for handlers and farmers so that a better vegetable quality could be offered to the population. More efficient monitoring is required by health authorities, requiring periodic assessments for parasites so that consumers may have a better life quality.

Research – Microbial contamination of grocery shopping trolleys and baskets in west Texas, 2020

Barf Blog

Indicator microorganisms evaluated were those detected by aerobic plate count (APC), yeast and molds (YM), Enterobacteriaceae (EB). Environmental listeria (EL), coliforms (CF), and E. coli (EC).  In addition, listeria monocytogenes, staphylococcus aureus, Escherichia coli O157 and salmonella sp. Were tested for.  Trolley grills (n=36) had 2.7 x 10CFU/cm2.  Trolley handles (n=36) had 2.7 x 10of CF and 5.2 CFU/cm2 of YM.  The bottom of handheld baskets (n=25) had 3.5 x 105 CFU/cm2 of CF and 5.07 CFU/cmof EC.  S. aureus was found on 96% of the baskets, 50% of the trolley handles (18 out of 36 samples), and 42% of the trolleys’ grills.  E. coli O157 was identified on 17% of baskets, 3% on trolley grills, and 3% on handles.  Salmonella sp. was detected on 16% of baskets and 8% of trolley grills.  L. monocytogenes was detected on 17% of the bottoms of handheld baskets but on none of the other samples. 

RASFF Alert – STEC E.coli – Coliforms – E.coli – Black Pepper Cheese

RASFF-Logo

RASFF – shigatoxin-producing Escherichia coli (stx1+ stx2+ /25g) and too high counts of coliforms (>150000 /g) and of Escherichia coli (>150000 /g) in black pepper cheese from Italy in Germany