This study aimed to investigate the behavior of Salmonella enterica and Listeria monocytogenes in processed date paste and syrup at different temperatures. Commercial products were inoculated with ...approximately 6 log CFU/mL of S. enterica or L. monocytogenes and stored at 4, 10, and 24°C for 90 days. S. enterica was able to survive in date products until the end of storage at 4°C. At this temperature, numbers decreased by 2.1 log CFU/g in date paste and by 3.4 log CFU/g in date syrup; however, at 10°C, cells were reduced >4.2 log CFU/g and were undetectable by direct plating in date paste or by enrichment (complete elimination) in syrup. Further, at 24°C, complete elimination of S. enterica was achieved in date paste and syrup by 30 and 7 days, respectively. L. monocytogenes numbers decreased by 1.4, 4.4, and >4.6 log CFU/g in date paste stored at 4, 10, and 24°C for 90 days, respectively. In date syrup, numbers of L. monocytogenes decreased to undetectable levels by 50, 14, and 4 days at 4, 10, and 24°C, respectively, by direct plating and complete elimination was observed at 10 and 24°C by 50 and 30 days of storage, respectively. The initial pH values of date paste and syrup were 4.7 and 4.8, respectively, and remained stable until the end of storage except for L. monocytogenes‐inoculated syrup.
Practical Application
Salmonella enterica and Listeria monocytogenes can easily survive in date paste and syrup particularly at refrigerator temperature, which explains the necessity of preventing the contamination of date products with foodborne pathogens.
Listeria monocytogenes, a contaminant of raw milk, includes hypervirulent clonal complexes (CC) like CC1, CC4, and CC6, highly overrepresented in dairy products when compared to other food types. ...Whether their higher prevalence in dairy products is the consequence of a growth advantage in this food remains unknown. We examined growth kinetics of five L. monocytogenes isolates (CC1, CC4, CC6, CC9, and CC121) at 37 and 4 °C in ultra-high temperature (UHT) milk and raw milk. At 4 °C, hypovirulent CC9 and CC121 isolates exhibit better growth parameters in UHT milk compared to the hypervirulent CC1, CC4, and CC6 isolates. CC9 isolate in raw milk at 4 °C exhibited the fastest growth and the highest final concentrations. In contrast, hypervirulent isolates (CC1, CC4, and CC6) displayed better growth rates in UHT milk at 37 °C, the mammalian host temperature. Proteomic analysis of representative hyper- (CC1) and hypovirulent (CC9) isolates showed that they respond to milk cues differently with CC-specific traits. Proteins related to metabolism (such as LysA or different phosphotransferase systems), and stress response were upregulated in both isolates during growth in UHT milk. Our results show that there is a Listeria CC-specific and a Listeria CC-common response to the milk environment. These findings shed light on the overrepresentation of hypervirulent L. monocytogenes isolates in dairy products, suggesting that CC1 and CC4 overrepresentation in dairy products made of raw milk may arise from contamination during or after milking at the farm and discard an advantage of hypervirulent isolates in milk products when stored at refrigeration temperatures.
Background: “Processed foods” are defined as any foods other than raw agricultural commodities and can be categorized by the extent of changes occurring in foods as a result of processing. ...Conclusions about the association between the degree of food processing and nutritional quality are discrepant. Objective: We aimed to determine 2000–2012 trends in the contribution of processed and convenience food categories to purchases by US households and to compare saturated fat, sugar, and sodium content of purchases across levels of processing and convenience. Design: We analyzed purchases of consumer packaged goods for 157,142 households from the 2000–2012 Homescan Panel. We explicitly defined categories for classifying products by degree of industrial processing and separately by convenience of preparation. We classified >1.2 million products through use of barcode-specific descriptions and ingredient lists. Median saturated fat, sugar, and sodium content and the likelihood that purchases exceeded maximum daily intake recommendations for these components were compared across levels of processing or convenience by using quantile and logistic regression. Results: More than three-fourths of energy in purchases by US households came from moderately (15.9%) and highly processed (61.0%) foods and beverages in 2012 (939 kcal/d per capita). Trends between 2000 and 2012 were stable. When classifying foods by convenience, ready-to-eat (68.1%) and ready-to-heat (15.2%) products supplied the majority of energy in purchases. The adjusted proportion of household-level food purchases exceeding 10% kcal from saturated fat, 15% kcal from sugar, and 2400 mg sodium/2000 kcal simultaneously was significantly higher for highly processed (60.4%) and ready-to-eat (27.1%) food purchases than for purchases of less-processed foods (5.6%) or foods requiring cooking/preparation (4.9%). Conclusions: Highly processed food purchases are a dominant, unshifting part of US purchasing patterns, but highly processed foods may have higher saturated fat, sugar, and sodium content than less-processed foods. Wide variation in nutrient content suggests food choices within categories may be important.
Background and Aim: Ready-to-eat (RTE) foods are widely used at home, restaurants, and during festivals in Bangladesh. So it is very important to investigate possible microbial contamination in RTE ...foods. Therefore, this study aimed to determine the total coliform count (TCC), isolate, identify, and characterize the Escherichia coli in RTE foods. The antimicrobial sensitivity of E. coli obtained from RTE foods was also performed using 12 commonly used antibiotics.
Materials and Methods: A total of 100 RTE food samples were collected aseptically and comprised of ten samples each: Burger, pizza, sandwich, chicken roll, chicken meat loaf, chicken fry, salad vegetable, ice-cream, yogurt, and milkshake sold in Mymensingh city. Samples were inoculated onto Eosin methylene blue agar and incubated at 37°C for 24 h. Isolation and identification of bacteria were performed based on cultural, staining, and biochemical properties, followed by a polymerase chain reaction.
Results: The TCC in Chicken meat loaf, burger, pizza, sandwich, salad vegetable ice-cream, and yogurt samples were 3.57 ± 0.96, 3.69 ± 0.08, 3.50 ± 0.60, 2.60 ± 0.20, 4.09 ± 0.29, 4.44 ± 0.25, and 3.14 ± 0.30 mean log colony-forming units ± standard deviation/mL, respectively. The study found a higher prevalence of E. coli in RTE salad vegetable products than in RTE meat and milk products. Forty percent of the mixed vegetable salad samples showed positive results for E. coli. Whereas E. coli prevalence in RTE meat and milk products was 20% and 16.7%, respectively. All the 21 isolates were subjected to antibiotic susceptibility test against 12 different antibiotics. It was observed that 46.1% were susceptible, 16.6% were intermediate, 46.1% were resistant, and 47.6% were multidrug-resistant (MDR) among seven different antibiotic classes. E. coli isolates were resistant to cephalexin, ceftazidime, oxytetracycline, and ampicillin and sensitive to gentamycin, followed by kanamycin, ceftriaxone, colistin, and enrofloxacin..
Conclusion: The study revealed that RTE foods are a serious issue from a public health point of view. To achieve a safer level of E. coli in RTE foods sold for human consumption, public food outlets must improve hygienic and good production procedures. Moreover, MDR E. coli in these foods pose serious public health threats.
•PPBFs stands for Precooked Plant Based Foods, including traditional and new dishes.•70% of the sample considers PPBFs useful to favour healthy diets.•Health Interest, Market Availability, and Time ...Pressure are the main PBCs.•High quality PPBFs can promote healthy diets of subjects under time pressure.•Clearly labelling health-giving properties of PPBFs encourages healthy choices.
Current lifestyles always pose increasing time pressure that can result in unhealthy diets. Our study addresses the role that high-quality plant-based convenience foods can play in promoting healthier consumptions. While convenience foods are in fact often associated with poor nutritional values, the spread of healthy convenience foods could respond to the needs of new lifestyles and promote better food choices. The study is based on a multicomponent model of the Theory of Planned Behaviour that has made it possible to verify how control factors such as cooking skills, product availability, budget, time pressure, and interest in healthy eating can affect the consumption of precooked plant-based foods. The results of Structural Equation Models applied to a sample representative of the Italian population (600 individuals) highlight the presence of a consistent group of consumers (almost 70%) that consider plant-based convenience foods as a useful means to improve their diet. For this cluster, the control factors that significantly influence behaviour are market availability, interest in healthy eating, and time pressure. The advancements in knowledge that this research produces are translated into guidelines for producers, retailers, and policy makers that, in synergy, might encourage consumers to replace unhealthy foods with healthy ones.
This research evaluated the effluent proportion of E. coli and ETEC in RTE meat products, characterized the isolated strains' clonal relatedness, and determined their antibiotic resistance. 130 RTE ...products were gathered from various restaurants and street fast food vendors in Duhok and Zakho Province. The Isolates of E. coli identified by culture methods were confirmed as ETEC by multiplex PCR of the identified virulence genes. ERIC-PCR was applied to establish the clonal relationships between strains. The disk diffusion method performed the susceptibility of antibiotics on the isolated ETEC. Out of 130 examined samples, 39 (30%) isolates of E. coli and 16 (12.3%) ETEC were detected. Pan-fried burgers were revealed to be the most frequent contaminated sample type, with both E. coli and ETEC 50% and 23.3%, respectively (P≤0.05). A high clonal dispersion (12 genotypes) was observed among the isolated ETEC strains. A strong genetic linkage was discovered between a few isolates retrieved from the same sample type and within the strains from the same geographic source area. A high antibiotic resistance rate was observed with total resistance to Amoxicillin/clavulanate, Clarithromycin, Doxycycline, Erythromycin, and Clindamycin. Isolates from burger samples showed a higher resistance rate when compared with the other sample types (P≤0.05). Multi-drug resistance was noticed in all ETEC isolates. RTE meat products sold in our area have a high rate of clonally heterogeneous carrying multi-drug resistant ETEC and may constitute a significant public health risk.
Foodborne diseases have always been a threat to human health. They are considered an emergent public health concern throughout the world. Many outbreaks have been found to be associated with biofilm. ...It is well documented that biofilm has become a problem in food industries as it renders its inhabitants resistant to antimicrobial agents and cleaning. In this review, biofilm formation in dairy, fish processing, poultry, meat, and Ready-To-Eat foods industries are discussed, as well as the biofilm forming abilities' of various microorganisms and the influence of food contact surface materials on biofilm formation. In addition, the conventional and emergent control strategies used to gain more proximity to efficiently maintain good hygiene throughout food industries is discussed.
Salmonella is a leading cause of foodborne disease worldwide and ready-to-eat (RTE) foods are regarded as a major source of infection and outbreak. In recent years, the consumption of Chinese RTE ...foods has raised markedly with the pace of life increasing. However, the prevalence of Salmonella in these foods in China and its potential risk to public health has not been well determined and evaluated. This study was undertaken to investigate the prevalence of Salmonella in Chinese retail RTE food products and to determine serotype distribution, antimicrobial resistance, virulence, and genetic diversity of recovered Salmonella isolates. Out of the 539 RTE food products collected and tested from July 2011 to May 2014, 19 (3.5%) were positive for Salmonella. The contamination levels of Salmonella were mostly in the range of 0.3–10 most probable number (MPN)/g, with one sample exceeding 110 MPN/g. Among the 50 isolates identified, 37 isolates (74.0%) were resistant to at least one antimicrobial, while 21 isolates (42.0%) were resistant to more than three antimicrobials. High rates of resistance were observed for tetracycline (56.0%), ampicillin (38.0%), and streptomycin (34.0%). PCR analysis of 15 virulence genes showed that the avrA, ssaQ, mgtC, siiD, sopB, and bcfC genes were detected in all 50 isolates, whereas the genes located on plasmid and prophage varied significantly among the isolates. Ten distinct serovars were identified and S. Derby, S. Meleagridis, S. Enteritidis, and S. Senftenberg were the most prevalent serovars. A total of 11 sequence types by multilocus sequence typing and 20 profiles by pulsed-field gel electrophoresis were generated for the 20 selected isolates and the combination of these two methods presented a better knowledge of genetic diversity of Salmonella isolates. The study provided a systematical surveillance on prevalence of Salmonella in Chinese RTE foods and indicates its potential risk to public health.
•High prevalence of Salmonella contamination in ready-to-eat foods was determined.•S. Derby, S. Enteritidis, S. Meleagridis were the predominant serovars recovered.•Salmonella isolates showed a high prevalence of antibiotic resistance.•Salmonella isolates exhibited a wide range of pathogenicity determinants.•The combination of MLST and PFGE presented a better knowledge of genetic diversity.
The Listeriamonocytogenes diversity throughout deboning, compressing and slicing of Spanish dry-cured ham processing among and within 6 production plants after cleaning and disinfection in two ...different seasons (autumn/winter and spring/summer) was evaluated in this work. L. monocytogenes isolates (n = 66), collected from deboning area (72.7%) and compressing and slicing areas (27.3%), were serotyped as 1/2b (65.1%), 1/2a (27.3%), 1/2c (6.1%) and 4b (1.5%) by PCR-based methods. The typing of the 66 isolates of L. monocytogenes by PFGE using the ApaI and SgsI enzymes revealed a high diversity with 52 pulsotypes and showed cross-contamination within each plant. The frequency of isolation of L. monocytogenes was higher in spring/summer than in autumn/winter. Although L. monocytogenes was not detected in any of the analyzed dry-cured ham samples, the presence of some pulsotypes and cross-contamination in the different industries suppose a hazard of contamination by this pathogen during deboning and slicing of dry-cured ham. The use of molecular typing techniques, such as PCR-based methods and PFGE characterization, could be used to trace the sources, distribution and routes of L. monocytogenes contamination throughout deboning and slicing of dry-cured ham.
•L. monocytogenes prevalence in dry-cured ham deboning and slicing areas was 9.16%.•Most of the L. monocytogenes in deboning and slicing areas were serotyped as 1/2b.•The frequency of L. monocytogenes was higher in spring/summer than in autumn/winter.•Cross-contamination between deboning, compressing and slicing areas was detected.
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