TDBBS is voluntarily recalling two pig ear pet treat products that were sold through Amazon.com for possible Salmonella contamination. No illnesses have been reported to date in connection with this recall of TDBBS pig ears.
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Category Archives: microbial contamination
Research – Preventative care: Increasing Hepatitis A vaccinations among food service workers
Thesis: Over the past three years, there has been an ongoing outbreak of Hepatitis A in the United States although it is the only foodborne disease that has a vaccination. Mandating vaccinations to food service workers is essential to reduce the spread of Hepatitis A, especially since outbreaks involving food handlers are in the public eye.
Background & Analysis: It is estimated that in the United States alone there are 48 million cases of foodborne illness annually. Out of these 48 million, 128,000 are hospitalized and 3,000 people die. The CDC recommends to the general public that the best way to prevent Hepatitis A is through vaccination, but not have explicitly stated that food service workers should be administered the vaccination. While food service workers are not traditionally designated as having an increased risk of Hepatitis A transmission, they are not free from risk. Additionally, 24% of Hepatitis A cases are asymptomatic which means a food-handler carrying the virus can unknowingly transmit the disease to a consumer. Historically, when an outbreak occurs local health departments start administering the vaccine for free or at a reduced cost. The funding from these vaccinations is through taxpayer dollars.
Germany – No impact on Campylobacter contamination from new rules
Stricter rules on Campylobacter have not yet led to a decrease in contamination based on figures from a German agency.
Almost a quarter of carcasses in the country had Campylobacter counts of more than 1,000 colony forming units per gram (cfu/g) in 2018, according to the Federal Office of Consumer Protection and Food Safety (BVL).
The process hygiene criterion of no more than 1,000 cfu/g on broiler carcasses at slaughterhouse level was introduced from January 2018 across the EU to determine the presence of Campylobacter spp. in the poultry meat chain. The aim is to prevent poultry meat with high levels of Campylobacter per gram being sold. If high levels are detected, the food business must improve hygiene.
In 2017, prior to introduction of the legislation, 22.7 percent of carcasses in Germany exceeded the levels. In 2018, the rate remained virtually unchanged at 22.6 percent. BVL said ongoing zoonotic monitoring will show to what extent the introduced threshold leads to an improvement in the situation.
Research – Evaluating the Antimicrobial Efficacy of White Mustard Essential Oil Alone and in Combination with Thymol and Carvacrol against Salmonella
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It is estimated that nontyphoidal Salmonella causes approximately 1 million illnesses and 378 deaths per year in the United States. Reduction of Salmonella-related foodborne infections can be achieved through application of food antimicrobials. Essential oils in combination with other antimicrobials can be added to food products to reduce the levels of the organism below the infectious dose for healthy individuals. The purpose of this study was to investigate the antimicrobial efficacy of white mustard essential oil (WMEO) against serovars of Salmonella and its potential to be used with carvacrol or thymol to control Salmonella. Results showed that WMEO at the highest concentration of 0.84% (v/v) compared with the positive control had approximately a 6- to 7-log reduction for all serovars. It was found that no difference in susceptibility existed among the serovars tested (P > 0.05). In addition, the MICs were determined to be 0.5, 0.02, and 0.02% for WMEO, carvacrol, and thymol, respectively, against Salmonella Typhimurium. The fractional inhibitory concentration index was calculated. A score of 1 indicated an additive effect occurred when WMEO was combined with thymol or carvacrol. Combining WMEO with carvacrol or thymol indicated that the concentration of individual essential oils needed to inhibit Salmonella can be reduced using these combinations and warrants further study to determine potential use in controlling Salmonella in commercial food products.
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WMEO showed no significant difference in antimicrobial activity between Salmonella serovars.
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The MIC of WMEO against Salmonella Typhimurium was 0.5%.
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Combination with thymol or carvacrol had an additive effect on the antimicrobial activity of WMEO.
Research – Occurrence and Abundance of Pathogenic Vibrio Species in Raw Oysters at Retail Seafood Markets in Northwestern Mexico
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Seafood has frequently been associated with foodborne illness because pathogens are easily introduced during seafood cultivation, handling, and processing. Vibrio parahaemolyticus and Vibrio cholerae are human pathogens that cause gastroenteritis and cholera, respectively, and Vibrio vulnificus can cause fatal wound infections and septicemia. However, information about the occurrence of these pathogens in oysters from the Pacific coast of Mexico is limited to V. parahaemolyticus. In the present study, we evaluated the presence and abundance of these three Vibrio species in 68 raw oysters (Crassostrea corteziensis) obtained from retail seafood markets in Sinaloa, Mexico. The most probable number (MPN)–PCR assay was used for amplification of the tlh (thermolabile hemolysin), ompW (outer membrane protein), and vvhA (hemolytic cytolysin) genes that are specific to V. parahaemolyticus, V. cholerae, and V. vulnificus, respectively. All oyster samples were positive for at least one Vibrio species. V. parahaemolyticus, V. cholerae, and V. vulnificus prevalences were 77.9, 8.8, and 32.3% overall, respectively, and most species were present in all sample periods with increased prevalence in period 3. The tdh (thermostable direct hemolysin) gene was detected in 30.1%, trh (TDH-related hemolysin) was detected in 3.7%, and tdh/trh was detected in 7.5% of the total tlh-positive samples (53 of 68), whereas the pandemic serotype O3:K6 (orf8 positive) was detected in only 1 sample (1.8%). The total prevalence of tdh and/or trh was 41.5%. In none of the samples positive for V. cholerae were the cholera toxin (ctxA) and cholix (chxA) toxigenic genes or the rfb gene encoding the O1 and O139 antigens amplified, suggesting the presence of non-O1 non-O139 V. cholerae strains. Our results clearly indicated a high prevalence of pathogenic Vibrio species in raw oysters from retail seafood markets in Mexico. Consumption of these raw oysters carries the potential risk of foodborne illness, which can be limited by cooking.
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V. parahaemolyticus, V. cholerae, and V. vulnificus were prevalent in raw oysters from Mexico.
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The tdh and trh genes and the pandemic O3:K6 serotype were detected in raw oysters.
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The ctxA and chxA genes, and O1/O139 serotypes were absent from V. cholerae–positive samples.
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The consumption of raw oysters represents a health risk for Vibrio infections.
Research – An Assessment of Listeriosis Risk Associated with a Contaminated Production Lot of Frozen Vegetables Consumed under Alternative Consumer Handling Scenarios
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Frozen foods do not support the growth of Listeria monocytogenes (LM) and should be handled appropriately for safety. However, consumer trends regarding preparation of some frozen foods may contribute to the risk of foodborne listeriosis, specifically when cooking instructions are not followed and frozen products are instead added directly to smoothies or salads. A quantitative microbial risk assessment model FFLLoRA (Frozen Food Listeria Lot Risk Assessment) was developed to assess the lot-level listeriosis risk due to LM contamination in frozen vegetables consumed as a ready-to-eat food. The model was designed to estimate listeriosis risk per serving and the number of illnesses per production lot of frozen vegetables contaminated with LM, considering individual facility factors such as lot size, prevalence of LM contamination, and consumer handling prior to consumption. A production lot of 1 million packages with 10 servings each was assumed. When at least half of the servings were cooked prior to consumption, the median risk of invasive listeriosis per serving in both the general and susceptible population was <1.0 × 10−16 with the median (5th, 95th percentiles) predicted number of illnesses per lot as 0 (0, 0) and 0 (0, 1) under the exponential and Weibull-gamma dose-response functions, respectively. In scenarios in which all servings are consumed as ready-to-eat, the median predicted risk per serving was 1.8 × 10−13 and 7.8 × 10−12 in the general and susceptible populations, respectively. The median (5th, 95th percentile) number of illnesses was 0 (0, 0) and 0 (0, 6) for the exponential and Weibull-Gamma models, respectively. Classification tree analysis highlighted initial concentration of LM in the lot, temperature at which the product is thawed, and whether a serving is cooked as main predictors for illness from a lot. Overall, the FFLLoRA provides frozen food manufacturers with a tool to assess LM contamination and consumer behavior when managing rare and/or minimal contamination events in frozen foods.
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A tool for frozen food manufacturers to assess listeriosis risk was developed.
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Scenarios of low-level L. monocytogenes in frozen vegetables did not typically result in illness.
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Listeriosis cases depended on model inputs related to consumer handling and initial concentration.
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Scenarios of more testing increased the probability of finding a contaminated lot and reduced risk.
Research -Predictive Model of Listeria monocytogenes Growth in Queso Fresco
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Listeria monocytogenes is a hardy psychrotrophic pathogen that has been linked to several cheese-related outbreaks in the United States, including a recent outbreak in which a fresh cheese (queso fresco) was implicated. The purpose of this study was to develop primary, secondary, and tertiary predictive models for the growth of L. monocytogenes in queso fresco and to validate these models using nonisothermal time and temperature profiles. A mixture of five strains of L. monocytogenes was used to inoculate pasteurized whole milk to prepare queso fresco. Ten grams of each fresh cheese sample was vacuum packaged and stored at 4, 10, 15, 20, 25, and 30°C. From samples at each storage temperature, subsamples were removed at various times and diluted in 0.1% peptone water, and bacteria were enumerated on Listeria selective agar. Growth data from each temperature were fitted using the Baranyi model as the primary model and the Ratkowsky model as the secondary model. Models were then validated using nonisothermal conditions. The Baranyi model was fitted to the isothermal growth data with acceptable goodness of fit statistics (R2 = 0.928; root mean square error = 0.317). The Ratkowsky square root model was fitted to the specific growth rates at different temperatures (R2 = 0.975). The tertiary model developed from these models was validated using the growth data with two nonisothermal time and temperature profiles (4 to 20°C for 19 days and 15 to 30°C for 11 days). Data for these two profiles were compared with the model prediction using an acceptable prediction zone analysis; >70% of the growth observations were within the acceptable prediction zone (between −1.0 and 0.5 log CFU/g). The model developed in this study will be useful for estimating the growth of L. monocytogenes in queso fresco. These predictions will help in estimation of the risk of listeriosis from queso fresco under extended storage and temperature abuse conditions.
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Growth of L. monocytogenes was examined in queso fresco at constant temperatures.
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A positive correlation was found between temperature and growth rate.
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A tertiary model was developed to predict growth under nonisothermal conditions.
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The acceptable prediction zone analysis suggests that the tertiary model was acceptable.
Research -Modeling the Effects of the Preculture Temperature on the Lag Phase of Listeria monocytogenes at 25°C
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In predictive microbiology, the study of the microbial lag phase, i.e., the time needed for bacteria to adapt to a new environment before multiplying, has received a great deal of attention in the research literature. The microbial lag phase is more difficult to estimate than the specific growth rate because the lag phase is impacted by the previous and actual growth environments. In this study, the growth of Listeria monocytogenes preincubated at 0, 5, 10, and 15°C and subsequently grown at 25°C was investigated at the single-cell and population levels. The population lag phase of L. monocytogenes was obtained by fitting the Baranyi model, and the single-cell lag time was estimated by the time to detection method. The lag phase at the single-cell and population levels of L. monocytogenes presented a downward trend as the preculture temperature ranged from 0 to 15°C. The population lag phase of L. monocytogenes was lower than the single-cell lag time at the same preculture temperature. In addition, except for the zero-lag distribution at a preculture temperature of 15°C, all the single-cell lag time distributions of L. monocytogenes followed a Weibull distribution under all preculture temperatures. The preculture temperature had a significant impact on the rapid variation in the single-cell lag time distribution. Thus, the influence of preculture temperature on the lag phase needs to be quantitatively analyzed for better assessment of microbiological risk.
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The variability of single-cell lag time could be described by the Weibull distribution.
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The population lag was shorter than the single-cell lag at the same preculture temperature.
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The preculture temperature had no significant effects on the growth rate.
Research – Prevalence of Campylobacter coli and Campylobacter jejuni in Retail Chicken, Beef, Lamb, and Pork Products in Three Australian States
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The aim of this study was to investigate the prevalence and distribution of Campylobacter species in a variety of fresh and frozen meat and offal products collected from retail outlets in New South Wales (NSW), Queensland (Qld), and Victoria (Vic). A total of 1,490 chicken, beef, lamb, and pork samples were collected from Australian supermarkets and butcher shops over a 2-year sampling period (October 2016 to October 2018). Campylobacter spp. were detected in 90% of chicken meat and 73% of chicken offal products (giblet and liver), with significantly lower prevalence in lamb (38%), pork (31%), and beef (14%) offal (kidney and liver). Although retail chicken meat was frequently contaminated with Campylobacter, the level of contamination was generally low. Where quantitative analysis was conducted, 98% of chicken meat samples, on average, had <10,000 CFU Campylobacter per carcass, with 10% <21 CFU per carcass. Campylobacter coli was the most frequently recovered species in chicken meat collected in NSW (53%) and Vic (56%) and in chicken offal collected in NSW (77%), Qld (59%), and Vic (58%). In beef, lamb, and pork offal, C. jejuni was generally the most common species (50 to 86%), with the exception of pork offal collected in NSW, where C. coli was more prevalent (69%). Campylobacter prevalence was significantly higher in fresh lamb (46%) and pork (31%) offal than in frozen offal (17 and 11%, respectively). For chicken, beef, and pork offal, the prevalence of Campylobacter spp. was significantly higher on delicatessen products compared with prepackaged products. This study demonstrated that meat and offal products are frequently contaminated with Campylobacter. However, the prevalence is markedly different in different meats, and the level of chicken meat portion contamination is generally low. By identifying the types of meat and offal products types that pose the greatest risk of Campylobacter infection to consumers, targeted control strategies can be developed.
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Retail chicken meat is frequently contaminated with low levels of Campylobacter.
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C. coli was more commonly detected in chicken meat and offal than C. jejuni.
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C. jejuni was more commonly detected in beef, lamb, and pork offal than C. coli.
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In nonchicken offal, prevalence of Campylobacter was highest on lamb offal.
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Prevalence of Campylobacter was higher in fresh than in frozen offal.
Research -Farmers and feed advisers encouraged to better test feed for mycotoxins
Premier Nutrition has encouraged farmers and feed advisers to take greater care in analysing incoming cereal samples to ensure accurate feed formulation, after analysis of the 2019 wheat and barley harvest revealed regional variations in protein and energy levels.
Eloise Lawlor, Premier Nutrition, explained that despite overall yields being recorded as higher than the five-year average, the harvest survey recorded decreased levels of protein in wheat.
“The national survey results have shown an average 0.4 percent drop in wheat protein levels, with energy also decreasing by 0.09MJ/kg” Lawlor said.
She explained that diverse weather conditions in the summer of 2019 has led to higher moisture levels, and therefore the decreased levels of energy were somewhat predictable. “To compensate for these deficits in protein and energy, soya and fat inclusions may increase in diet formulations,” she added,
Lawlor confirmed that although wetter conditions have influenced energy content, which would normally be predicted to increase the levels of mycotoxins, average mycotoxin levels across the UK have remained low.
