Ready-to-eat Food Products Research Articles

Trend-Driven Innovation for RTE Food Market: A Comparison Study Between Consumers from Malaysia and Indonesia

The ready-to-eat (RTE) food market is growing worldwide. Nevertheless, a limited study was found where researchers compare consumer behavioral intention toward RTE foods between countries. This study compares consumers in Malaysia and Indonesia regarding their food preferences and behavioral intentions toward RTE foods. Using a quantitative cross-sectional approach, the researchers developed an online survey and distributed the survey link to consumers aged 18 years and above from both countries via social media platforms. The dataset comprised 321 responses from Malaysia and 262 from Indonesia. Based on the analyses, findings reported some similarities and differences in consumer preferences and behavior intention between both countries. The highest percentages of Malaysian respondents were recorded for plant-based, genetically modified, gluten-free, and allergen-free foods. Interestingly, the highest percentage of Indonesian respondents reported for insect-based food than the Malaysians. More Malaysian consumers preferred ethnic foods from different cultures than Indonesians. About the same highest percentages of consumers from both countries preferred cell-cultured meat, 3D printed foods, and vegan foods. For Malaysian samples, attitude and subjective norms significantly influenced their behavior intention toward RTE foods. For Indonesian samples, subjective norms and behavioral control significantly influence consumer behavior intention toward RTE foods. Findings are relevant for food producers and marketers to explore the young consumer market and to identify new products to fulfill the market demand. This study broadens and deepens the current understanding of both countries' RTE food trends and consumer behavioral patterns. Food producers should promote RTE food products by highlighting their benefits through marketing channels.

Prevalence and growth potential of Listeria monocytogenes in innovative, pre-packed, plant-based ready-to-eat food products on the Belgian market

In recent years, pre-packed ready-to-eat (RTE) food products on the Belgian market have shifted to a more plant-based composition due to a variety of reasons, including consumer concerns about health, animal welfare, and sustainability. However, similar to animal-based RTE foods, plant-based RTE foods can be susceptible to the presence and outgrowth of Listeria monocytogenes (L. monocytogenes). Three innovative, pre-packed, plant-based RTE food product categories on the Belgian market were identified based upon data gaps regarding the prevalence and growth potential of this pathogen. These were vegetarian and vegan deli sandwich slices (category 1), fresh-cut (mixes of) leafy vegetables (category 2), and multi-ingredient salad bowls (category 3). Reports on associated listeriosis outbreaks and recalls were collected and a comprehensive literature review on the prevalence of L. monocytogenes (i.e. detection in 25 g food) was performed. In addition, the prevalence of L. monocytogenes was also determined through an exploratory retail survey of ca. 50 different RTE products of each category. A batch was considered positive if L. monocytogenes was detected in a food item, either on the day of purchase, at the end of shelf life, or both. During the retail survey, L. monocytogenes was not detected in category 2 (0 out of 51 batches), while 1 out of 51 and 6 out of 48 batches were found positive for respectively category 1 and 3. The observed L. monocytogenes concentration did not exceed 10 CFU/g at any point in time in any batch. Furthermore, challenge tests were performed to determine the growth potential of L. monocytogenes in nine pre-packed, plant-based RTE food products (two to four different products of each category, and three different batches per product). After inoculation, products were stored for half of their shelf life at 7 °C and half of their shelf life at 9 °C (simulation of resp. retail and consumer storage). In six of the nine challenge tests executed, growth of L. monocytogenes was supported (i.e. growth potential ≥0.50 log10 CFU/g during shelf life). The highest growth potential was observed for fresh-cut iceberg lettuce (3.60 log10 CFU/g in 9 days), but a large variation regarding the growth potential of L. monocytogenes was noted both between and within the three studied pre-packed, plant-based RTE food product categories. This variation was mainly caused by differences in product composition, physicochemical product characteristics, present (competitive) microbiota such as lactic acid bacteria, applied preservation techniques, and shelf life.

Factors that Influence the Buying Behaviour of Ready to Eat Food Products

The present investigated was conducted at Dadri, Gautam Buddh Nagar, UP. Out of 50 respondents this data has been collected from research area. 13% people opinion is about RTE food is easily available now days in the market. 14% consumers purchase the food on the basis of their taste. About 8% people buying that food because their family preferand like the ready to eat food and 1% people are those who are buying that food to influence by other and 10% also those were convenient from other users. Mostly around 15% consumers were those always buying consuming the RTE food for saving their cooking and preparation time. In the end rest 0% people nil due to the no data.
 On the other hand, there were few respondents out of 100% those have valid reason based on their past consumption experience to purchase ready to eat (RTE) food. Firstly, there was around 4% people those were unable to buy RTE food due to the lack of their awareness and knowledge also. Approximately 6% consumers were those who dislike the RTE products due to any valid reason. Around 26% people were not able to buy the RTE food products due to the high price of product. Nearby 20% consumers dislike the products due their low quality.
 4% consumers were unable to buy the RTE food products due to the unavailability. Approximately 34% people dislike the products because according to them, Ready to Eat food are too much health conscious because those are available in the form of extra fat, extra fibers, etc. Less than 6% consumers are those who haven’t any valid reason to buy RTE food products.

Consumers’ attitudes toward refrigerated ready-to-eat meat and dairy foods

Abstract The constant variation of people’s lifestyle has been linked to changes in people’s eating habits. The consumption of ready-to-eat (RTE) food products, such as fresh vegetables, salads, dairy, pre-cooked meat, or pre-cooked meals, has increased in all western countries. This study aims at characterization of the Portuguese consumers’ attitude toward chilled RTE meat and dairy foods consumption. The study was performed using a questionnaire survey disclosed through an internet platform. The sample consisted of 350 individuals, who voluntarily answered the questionnaire. The survey included questions to characterize the Portuguese purchase and food safety attitudes related to dairy and meat RTE food products. The questionnaire also included questions for the sociodemographic characterization of the sample involved. According to the results, it is not clear to the customers as which is the safer refrigerated RTE food selling format, pre-packed or foods on request. The participants consider refrigerated RTE dairy and meat food products safer when purchased at the delicatessen department in the supermarket than those purchased at open markets or bazaars. With respect to the customers’ habits, they usually purchase RTE dairy or meat food products mainly from the supermarket, and in pre-packed format. Globally, the results reveal that Portuguese consumers are conscious and follow assertive attitudes toward food safety, contributing to maintain the refrigerated food chain, even when they take the product home.

Microbial safety of ready-to-eat food sold by retailers in Thohoyandou, Limpopo province, South Africa

Problems of foodborne diseases relating to the microbiological quality/safety of food continue to be of big concern globally. The study was undertaken to assess the microbial safety of ready-to-eat (RTE) foods sold in retailers around Thohoyandou, Limpopo province, South Africa. A total of 96 RTE food products were purchased from four (4) different retailers and transported to a laboratory for analysis. Food handling practices, personal hygiene and pest control measures were observed and recorded. To enumerate Coliform, Salmonella species, Staphylococcus aureus, Bacillus cereus, Escherichia coli, total plate count, Yeasts and Moulds serial dilution of (10−1 − 10−5) and pour plate/spread method were employed. The checklist on the retailers revealed that they followed good manufacturing practice and good personal hygiene expect retailer 4. Microbial counts for all samples ranged from 1.10 to 3.95 log x cfu/g. Bacillus cereus and yeasts counts for all samples ranged from 1.71 to 3.95 and 1.43 to 3.73 log x cfu/g, respectively. S. aureus and coliforms mean counts ranged from 1.10 to 2.68 and 1.53 to 3.58 log x cfu/g. Total plate count ranged from 2.12 to 3.91 log x cfu/g for all the retailers. Moulds and Salmonella were not detected in all the samples tested. Indole test confirmed positive E. coli and citrate test confirmed positive for S. aureus and B. cereus. Mean counts of some microorganisms were above satisfactory microbial limits, and this may pose hazard to public health.

Impact of lactic acid bacteria on the control of Listeria monocytogenes in ready-to-eat foods

Abstract Due to the increased demand for ready-to-eat (RTE) minimally processed foods, alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded. A significant safety hazard in RTE food products is the growth of the foodborne pathogen Listeria monocytogenes (L. monocytogenes). After processing, recontamination or cross-contamination of L. monocytogenes in RTE food products may occur and the lack of cooking can lead to an increased risk of listeriosis. Further, some RTE food products (e.g. cheese and cured meat) can have a long processing period and shelf life, thus allowing for the growth and proliferation of L. monocytogenes in the food matrix. Lactic acid bacteria (LAB) are generally recognized as safe probiotics and have been proposed as a biological control approach to eliminate foodborne pathogens including L. monocytogenes. LAB have been reported to extend the shelf life of food products and inhibit pathogen proliferation via growth competition and metabolite production. LAB are native microflora of many RTE foods, but only certain LAB may inhibit pathogen growth. Therefore, the specificity of LAB species should be employed in their use in RTE foods. This review will discuss the antimicrobial mechanisms of LAB against L. monocytogenes, selective use of LAB in food matrices, and their uses in food processing and packaging.

Occurrence, serovars and antibiotic resistance of Salmonella spp. in retail ready-to-eat food products in some Chinese provinces

Ready-to-eat (RTE) food products have been involved in numerous outbreaks of salmonellosis; however, epidemiological studies and data concerning Salmonella spp. contaminants of these foods are lacking in China. During 2015.6–2016.6, a total of 300 retail RTE food products were collected from 15 provincial capitals of China to determine the prevalence of Salmonella spp. and investigate serovar distribution and antibiotic resistance of the recovered isolates. Overall, seven (2.3%) of the food samples were contaminated by Salmonella spp. and the MPN values ranged from 0.3 to >110 MPN/g. Of the 26 recovered Salmonella isolates, eight serovars and eight MLST patterns were detected, with Salmonella enterica serovar Derby ST40 being the most prevalent. All isolated Salmonella serovars have previously been implicated in human infections. Eighty percent of the isolates were resistant to at least one antibiotic class, and thirty percent were multidrug-resistant. The isolates had the highest resistance rates to tetracycline (70.0%), with tet(A) at 60.0% and tet(B) at 10.0%. The occurrence of Salmonella spp. and the high antibiotic-resistance rates of the isolates detected in the RTE foods could be potential human health risks. These results indicate that further supervision and hygienic regulations are needed in the RTE food production chain to ensure microbiological safety.

Genetic diversity of Listeria monocytogenes isolated from ready-to-eat food products in retail in Poland

The study describes the characterization of Listeria monocytogenes isolated from the general 2017–2019 national official control and monitoring sampling program. A total of 60,928 of ready-to-eat (RTE) food products were collected in retail in Poland, while the number of L. monocytogenes contaminated samples was 67 (0.1%). The majority of the strains belonged to molecular serotype IVb followed by IIa, frequently associated with human listeriosis. Furthermore, 61.2% of the isolates were resistant at least to one of the tested antimicrobials: penicillin, ampicillin, meropenem, erythromycin, sulfamethoxazole-trimethoprim, amoxicillin-clavulanic acid, ciprofloxacin, chloramphenicol, gentamicin, vancomycin, tetracycline and rifampicin. Virulence genes inlA, inlC, inlJ and lmo2672 were detected in all of the isolates. In our study the llsX gene (encoding LLS) exhibited 11.6% positivity. The 32 strains were grouped into 12 clonal complexes (CCs) which belong to the major clones that are in circulation in Europe. Among them, seven strains with the cgMLST close relatedness (CC2) were isolated from diverse food sectors, underlining a large circulation of this clone in Poland, most likely from multiple introduction sources. Additionally, two RTE strains CC6 and one CC37 were identified as closely related by cgMLST to two publicly available genomes of clinical strains isolated in Poland in 2012–2013. These results indicate the large strain circulation and point to RTE food products as a potential source of human listeriosis.The present study provided data to capture the contamination status of L. monocytogenes in foods at the retail level in Poland and assess the potential risk of this pathogen for human safety.

Microbiological quality of ready-to-eat food products in southern Taiwan

This study was to assess the microbiological quality of commercial ready-to-eat (RTE) food products sold in southern Taiwan. A total of 126 RTE food samples, including staple, meat, seafood, and vegetarian food products, were purchased from traditional markets, supermarkets, and warehouse stores. These foods were kept at refrigerator, room temperature, or hot stored at the time of sale. Aerobic plate count (APC), coliform, Escherichia coli, and Staphylococcus aureus were evaluated. APC in excess of 5 log CFU/g was obtained in traditional markets (27 samples), supermarkets (20 samples), and warehouse stores (15 samples). Seafood products were the most contaminated compared to staple products, meat products, or vegetarian foods. The highest incidence of APC greater than 5 log CFU/g was detected from food products stored at room temperature. Refrigerator stored food products were the second incidence, followed by hot kept food products. No significant differences were found for coliform and E. coli among the various markets or food types (p > 0.05). RTE food products sold in the traditional market, supermarkets, and warehouse stores contaminated with S. aureus were 19.0%, 12.7%, and 9.5%, respectively. The percentage of samples over-contaminated with S. aureus was 15.9% (seafood), 9.5% (staple and meat products), and 6.3% (vegetarian food products). RTE food products stored at room temperature had the highest contamination of S. aureus, followed by refrigerator and hot stored food products (p < 0.05).

Fate of Listeria monocytogenes in Ready-to-Eat Refrigerated Dips Treated with High Pressure Processing

Various outbreaks and recalls have been associated with Listeria monocytogenes contamination of ready-to-eat (RTE) food products, including dips. High pressure processing (HPP) is useful for reducing levels of bacteria in many RTE food products, but its efficacy for reduction of pathogens in RTE dips is not well understood. In this study, laboratory-prepared hummus, tahini, baba ghanoush, guacamole, and pesto were initially treated with HPP at 350 MPa for up to 240 s to assess L. monocytogenes inactivation and determine D-values. D350 MPa-values in hummus, guacamole, and baba ghanoush were 105.3, 71.3, and 34.0 s, respectively. No significant reduction in L. monocytogenes levels was observed in tahini or pesto at 350 MPa for 240 s or after additional treatment for up to 600 s at 600 MPa (P > 0.05). Overall, the results of this study highlight the efficacy of HPP for reducing L. monocytogenes levels in certain RTE dips and but not in others.

Antimicrobial Resistance, Virulence Determinants, and Biofilm Formation of Enterococcus Species From Ready-to-Eat Seafood.

Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp (n = 288), boiled shrimp (n = 216), and smoked shrimp (n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby–Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis, 17 (28.8%); E. faecium, 29 (49.2%); E. gallinarum, 6 (10.2%); E. casseliflavus, 2 (3.4%); E. hirae, 3 (5.1%); and E. durans, 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3–11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: ermA, 13/29 (44.8%); vanA, 14/22 (63.6%); tetA, 14/27 (51.9%); tetM, 15/27 (55.6%); ermB, 4/29 (13.8%); and vanB, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum, and E. hirae. This study further revealed that RTE food products are reservoirs of potential virulent enterococci with antibiotic-resistant capabilities. This provides useful data for risk assessment and indicates that these foods may present a potential public health risk to consumers.

MecA-related structure in methicillin-resistant coagulase-negative staphylococci from street food in Taiwan

Antibiotic-resistant patterns, a mecA homologue complex, and staphylococcal cassette chromosome mec (SCCmec) were analysed in samples of ready-to-eat (RTE) street food in Taiwan. RTE food samples (270) were collected in three densely populated Taiwanese cities between June and November 2014. Among 14 strains being identified as methicillin-resistant coagulase-negative staphylococci (MRCoNS), genetic diversities was determined by PFGE analysis. SCCmec types IV, V, VIII and TXG-24 were detected in 9, and mecASs (a mecA homologue) detected in 8. The mecASs gene complex from S. sciuri subsp. sciuri TXG-24 was found to be closely related to those found in both S. sciuri subsp. sciuri (ATCC29062) and S. sciuri subsp. rodentium (ATCC700061). SCCmecTXG24 carries a class A mec complex, a ccrA5B3-like gene complex, a heavy metal gene complex, and an IS1216 mobile element carrying tet(S). Matching identity to ccrA5 was 84.5% for ccrA in S. pseudintermedius KM241. Matching identify to ccrB3 was 92.1% for ccrB in S. pseudintermedius AI16. Similar ccrA and SCCmec boundary sequences suggest that SCCmec is easily transmitted to coagulase-negative staphylococci (CoNS). Based on MRCoNS strains identified in this research, Taiwanese RTE food products likely carry multiple antibiotic resistance genes that can be transmitted to hospitals and other clinical settings.

Listeria monocytogenes in Retail Delicatessens: An Interagency Risk Assessment—Risk Mitigations

Cross-contamination, improper holding temperatures, and insufficient sanitary practices are known retail practices that may lead to product contamination and growth of Listeria monocytogenes. However, the relative importance of control options to mitigate the risk of invasive listeriosis from ready-to-eat (RTE) products sliced or prepared at retail is not well understood. This study illustrates the utility of a quantitative risk assessment model described in a first article of this series (Pouillot, R., D. Gallagher, J. Tang, K. Hoelzer, J. Kause, and S. B. Dennis, J. Food Prot. 78:134-145, 2015) to evaluate the public health impact associated with changes in retail deli practices and interventions. Twenty-two mitigation scenarios were modeled and evaluated under six different baseline conditions. These scenarios were related to sanitation, worker behavior, use of growth inhibitors, cross-contamination, storage temperature control, and reduction of the level of L. monocytogenes on incoming RTE food products. The mean risk per serving of RTE products obtained under these scenarios was then compared with the risk estimated in the baseline condition. Some risk mitigations had a consistent impact on the predicted listeriosis risk in all baseline conditions (e.g. presence or absence of growth inhibitor), whereas others were greatly dependent on the initial baseline conditions or practices in the deli (e.g. preslicing of products). Overall, the control of the bacterial growth and the control of contamination at its source were major factors of listeriosis risk in these settings. Although control of cross-contamination and continued sanitation were also important, the decrease in the predicted risk was not amenable to a simple solution. Findings from these predictive scenario analyses are intended to encourage improvements to retail food safety practices and mitigation strategies to control L. monocytogenes in RTE foods more effectively and to demonstrate the utility of quantitative risk assessment models to inform risk management decisions.

Successful management of Listeria spp. in an avocado processing facility

Listeria monocytogenes can grow and multiply in various food matrices and cause severe human illness. Apart from the influence on consumer health, L. monocytogenes contamination of ready-to-eat (RTE) food products causes major economic losses due to product recalls. Control of foodborne pathogens in RTE food products is a challenge, specifically in foods that cannot undergo a heat-treatment during processing. The aim of this study was to develop control strategies for the management of L. monocytogenes in an avocado processing facility, additional to a quality control system. An in-house monitoring system (IMS) was established to test specifically for Listeria spp. in the final products and processing environment, including floors, equipment, work areas and personnel. Guacamole and environmental samples were collected and tested on-site for Listeria with the ISO 11290-1 method. Based on the prevalence of Listeria, the facility introduced new strategies in processing to counter cross contamination. Results from the 2014 guacamole production season showed almost complete eradication of Listeria spp. in final products (0.17%, n = 1170) and the processing facility (0.79%, n = 1520). This is a major achievement since the highest incidence of Listeria spp. over a period of five years was measured at 11.39% (n = 948) in the final product during the 2013 season and 13.44% (n = 1927) in the processing facility in 2011. These results indicate that successful management of Listeria spp. in an avocado processing facility can be accomplished with in-house monitoring of the listerial population and subsequent adjustments to the processing system.

Prevalence, antimicrobial resistance and genetic diversity of Salmonella isolated from retail ready-to-eat foods in China

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.

English

Recontamination of ready-to-eat (RTE) products during post-processing may be the cause of outbreaks of food-borne disease. In this study, a total of 150 RTE samples were obtained for bacteriological examination (coliforms, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, Psychrotrophic bacteria and Psychrophilic bacteria). Various types of RTE food products that contained frozen (cooked and semi-cooked) and refrigerated (cooked) poultry meat foods, were purchased randomly periodically in January and March, 2012. 65% of cooked samples and 62% of semi cooked samples contain more than 102 CFU/g coliform, while S. aureus was more than 102 CFU/g in 35 and 40% of samples, respectively. Also 28% of cooked samples and 44% of semi cooked samples contained E. coli. 14% of all samples were contaminated by Salmonella. The results for enumeration of B. cereus, psychrophilic and psychrotrophic microorganisms were: 2/96 &plusmn; 0/09 log CFU/g, 5/02 &plusmn; 1/77 log CFU/g and 3/05&plusmn;0/04 log CFU/g, respectively. &nbsp; Key words: Foodborne pathogens, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, psychrotrophic bacteria, psychrophilic bacteria, cooked, semi-cooked.

Analysis of Older Adults’ Domestic Kitchen Storage Practices in the United Kingdom: Identification of Risk Factors Associated with Listeriosis

Increased listeriosis incidence among older adults (≥60 years) has been reported internationally, with many cases reported to be sporadic and associated with ready-to-eat (RTE) food products with extended refrigerated shelf life. Given that the home kitchen is recognized as a significant location where foodborne illnesses are acquired, it is important that consumers implement safe food practices to minimize risks. This is crucial for vulnerable consumers, such as older adults. Consumer food safety recommendations in the United Kingdom to reduce the risk of listeriosis at home include (i) following “use-by” dates on unopened prepacked RTE food products, (ii) consuming RTE food products within 2 days of opening, and (iii) ensuring the safe operating temperatures of domestic refrigerators (≤5°C). This study utilized observation, self-reporting, and microbiological analysis to determine actual food storage practices to identify behavioral risk factors. A domestic kitchen survey was conducted in older adult (≥60 years) consumers’ domestic kitchens (n = 100) in South Wales, United Kingdom. Forty-one percent of foods in home refrigerators were beyond the use-by date, of which 11% were unopened RTE food products commonly associated with listeriosis. Sixty-six percent of opened RTE foods had been or were intended to be stored beyond the recommended 2 days after opening. Older adults failed to ensure safe refrigeration temperatures, with 50% of central storage and 85% of door storage areas operating at temperatures >5°C. Older refrigerators operated at significantly (P < 0.05) higher temperatures. Given that Listeria monocytogenes was isolated in 2% of kitchens, these findings suggest that storage malpractices may have a greater effect on the potential risk of listeriosis than its presence alone. The study has determined that many older adults fail to adhere to recommendations and subject RTE foods associated with L. monocytogenes to prolonged storage at unsafe temperatures which may render food unsafe for consumption.

Cold atmospheric pressure plasma treatment of ready-to-eat meat: Inactivation of Listeria innocua and changes in product quality

The application of cold atmospheric pressure plasma for decontamination of a sliced ready-to-eat (RTE) meat product (bresaola) inoculated with Listeria innocua was investigated. Inoculated samples were treated at 15.5, 31, and 62 W for 2–60 s inside sealed linear-low-density-polyethylene bags containing 30% oxygen and 70% argon. Treatments resulted in a reduction of L. innocua ranging from 0.8 ± 0.4 to 1.6 ± 0.5 log cfu/g with no significant effects of time and intensity while multiple treatments at 15.5 and 62 W of 20 s with a 10 min interval increased reduction of L. innocua with increasing number of treatments. Concentrations of thiobarbituric acid reactive substances (TBARS) increased with power, treatments and storage time and were significantly higher than those of control samples after 1 and 14 days of storage at 5 °C. However, the levels were low (from 0.1 to 0.4 mg/kg) and beneath the sensory threshold level. Surface colour changes included loss of redness of ∼40% and 70% after 1 and 14 days of storage, respectively, regardless of plasma treatment. The results indicate that plasma may be applicable in surface decontamination of pre-packed RTE food products. However, oxidation may constitute an issue in some products.

Prevalence and classification of toxigenic Staphylococcus aureus isolated from refrigerated ready-to-eat foods (sushi, kimbab and California rolls) in Korea

To investigate the presence of toxigenic Staphylococcus aureus in ready-to-eat (RTE) Korean foods and determine the distribution of genes related to various types of toxin production. A total of 3293 commercial RTE refrigerated foods (sushi, n = 1882; kimbab, n = 975; California rolls, n = 436) were collected from Korean grocery stores, department stores and convenience stores between January 2006 and June 2007. Of these, 197 (5.98%) RTE samples were contaminated with coagulase-positive Staph. aureus, that is, 61 (6.26%) kimbab, 110 (5.84%) sushi and 26 (5.96%) California rolls. Multiplex PCR determined the presence of 12 toxigenic genes: sea, seb, sec, sed, see, seg, seh, sei, sej, tst-1, eta and etb. Approximately half (49.75%) of the Staph. aureus isolates had toxigenic properties, and most of the toxigenic isolates possessed genes coding for the simultaneous production of two or more types of toxin. The most frequent toxigenic types found in Korean RTE foods were as follows: seg = sei > sea > tst-1 > etb > seh > eta > sec > sej. This study provided a comprehensive analysis of toxigenic S. aureus isolates from Korean RTE foods and their toxigenicity types. This emphasizes the potential risk of various types of toxigenic Staph. aureus in refrigerated RTE food products, which should be better managed to establish safer food chains in global food markets. This result may contribute to an extended database on Staph. aureus food contamination and mitigate the lack of available information on microbiological hazards in Southeast Asian Nations.

Impact of Nitrite on Detection of Listeria monocytogenes in Selected Ready‐to‐Eat (RTE) Meat and Seafood Products

The impact of sodium nitrite (NaNO2) on detection and recovery of Listeria monocytogenes from select ready-to-eat (RTE) foods including smoked salmon, smoked ham, beef frankfurters, and beef bologna was assessed. Nitrite-containing (NC; 100 to 200 ppm NaNO2) or nitrite-free (NF) foods were inoculated with a 5-strain cocktail of L. monocytogenes by immersion into Butterfield's buffer solution containing 5.4 to 7.4 x 10(3) L. monocytogenes per milliliter. Inoculated products were vacuum-packaged and stored at 5 degrees C. A weekly comparative analysis was performed for presence of L. monocytogenes using 5 detection methods on products held at 5 degrees C for up to 8 wk. L. monocytogenes initially present at <100 CFU/g during the first 2 wk of storage increased throughout the study, attaining final populations of approximately 1 x 10(4) to 1 x 10(5) CFU/g. Lactic acid bacteria predominated throughout the study in all products. Exposure to NaNO2 (100 to 200 ppm) resulted in 83% to 99% injury to the L. monocytogenes strains tested. The genetic-based BAX System (DuPont Qualicon, Wilmington, Del., U.S.A.) and modified USDA/FSIS methods detected 98% to 100% of Listeria-positive food samples and were consistently superior to and significantly different (P < 0.05) from conventional cultural methods in recovering Listeria from NC samples. Data show that nitrite-induced injury adversely affects detection and recovery of L. monocytogenes from NC food, confirming earlier findings that nitrite-induced injury masks L. monocytogenes detection in NC RTE food products. Nitrite-injured Listeria can subsequently repair upon nitrite depletion and grow to high levels over extended refrigerated storage.