Modelling survival behaviour of Salmonella enterica ser. Enteritidis,Typhimurium and Tennessee on table eggs during storage at different temperatures

Quantitative risk assessment studies on the health risk of Salmonella due to consumption of contaminated table eggs are based on the assumption that Salmonella is inside the egg and that the pathogen belongs to serovar Enteritidis. However different serovars of Salmonella may contaminate the surface of table eggs and spread to other foods at consumer's kitchen due to improper food handling. In the present study the survival behaviour of one strain each from Salmonella enterica serovars Enteritidis, Typhimurium and Tennessee on table egg surface during storage at 4, 8, and 20 °C have been described. Besides, in those cases observed data were subjected for modelling; linear, log-linear tail and Weibull models were compared in terms of model fitting and model performance. Overall, in most cases, inactivation kinetics presented a linear trend on Salmonella behaviour so that Weibull and linear models adequately described observed data. Regarding log-linear tail models, though they presented a better fitting, their adequacy could not be assessed given the lack of data in the tail region. Regarding storage temperatures, 4 °C was predicted to be the most inhibitory temperature for table eggs externally contaminated by a strain of S. enterica serovar Enteritidis. After 28 days of storage, a reduction of 4 log₁₀ cfu/g of eggshell on the S. enterica ser. Enteritidis load was registered at 4 °C. S. enterica ser. Typhimurium and Tennessee showed higher survival rates at all tested temperatures. The results highlighted the importance of keeping constant the storage temperature of table eggs in order to reduce the risk of S. enterica ser. Enteritidis contaminating the surface of table eggs. However this temperature might not be the optimal one in view of S. enterica serovars other than Enteritidis.     

Effect of natural-style processing on the oxidative and hydrolytic degradation of the lipid fraction of table olives

The aim of this work was to determine the effect of natural-style processing, by using three different cultivars, on the oxidative and hydrolytic degradation of the lipid fraction of table olives. Samplings were made at harvest and after 4 and 8 months of processing. The Italian table olive cultivars Bella di Cerignola, Termite di Bitetto, and Peranzana, diffused in the Apulia region, were considered. During processing, the total phenols content of the lipid fraction decreased from 381–417 mg/kg oil to 106–125 mg/kg oil, depending on the cultivar. The level of primary oxidation at the end of processing was relatively low, as compared to high quality lipids such as extra virgin olive oil: peroxide value and oxidized triacylglycerols accounted for 11.7–13.1 meq O₂/kg oil and 3.3–7.1 g/kg respectively, depending on the cultivar. A very modest secondary oxidation occurred, as shown by final amounts of triacylglycerol oligopolymers ranging from 0.6 to 0.9 g/kg. On the contrary, a relevant hydrolytic degradation was observed, with free fatty acids accounting for 2.04–2.25 g/100 g oleic acid and diacylglycerols in the range 45.4–48.0 g/kg, at the end of processing. The polar compounds, mainly represented by diacylglycerols, reached values in the ranges 41.1–55.9 g/kg after 4 months and 58.0–62.0 g/kg after 8 months.     

Antimicrobial resistance of Salmonella spp. and Escherichia coli isolated from table eggs

The antimicrobial sensitivity of Salmonella spp. and Escherichia coli isolated from the shells and contents of table eggs sampled from sale outlets in Trinidad was determined using the disc diffusion method. The phage types of S. Enteritidis isolates, the phenotypic characteristics of E. coli isolates and the presence of O157 strain were also investigated. Of a total of 74 isolates of Salmonella tested, 17 (22.9%) exhibited resistance to one or more of the seven antimicrobial agents used compared with 104 (88.1%) of 118 E. coli isolates. The difference was statistically significant (P < 0.05; X²). For both microorganisms, resistance was relatively high to streptomycin (54.2%) and tetracycline (35.9%) but low to gentamicin (11.5%) and sulphamethoxazole/trimethoprim (9.4%). Only 1 (1.4%) isolate of Salmonella was multi-resistant while 55 (46.6%) of E. coli isolates were resistant to three or more antimicrobial agents. The frequency of resistance to antimicrobial agents amongst both bacteria was not significantly (P > 0.05; X²) affected by the location of isolation on the egg (shell or content) or source of eggs (farms, shopping malls or other retailers). Eight (19.5%) of 41 S. Enteritidis isolates tested were resistant compared to 4 (26.7%) of 15 isolates of S. Ohio. All S. Enteritidis isolates belonged to phage type 1 (PT1) and all E. coli isolates were non-haemolytic, non-mucoid, sorbitol fermenters and non-O157 strains. It was concluded that the relatively high resistance amongst the bacteria tested could pose therapeutic problems in consumers, particularly in egg-borne salmonellosis or colibacillosis.     

Occurrence and antimicrobial resistance of enterococci in retail foods

This study aimed to show the vancomycin-resistant enterococci VRE contamination and antibiotic resistance profiles of Enterococcus spp. in different kinds of food acquired from various markets between January 2007 and June 2007. Two hundred samples were used in the research. They consisted of 50 samples of meat (20 chicken, 20 beef, 10 fish), 50 samples of cheese (20 cheddar, 20 Turkish white, 10 cream), 50 samples of RTE (10 burgers, 10 pizzas, 10 chicken nuggets, 10 milk deserts, 5 beef roast and 5 salads), 30 samples of spice (10 black pepper, 10 red pepper, 10 curry) and 20 samples of yogurt. The results of the study indicated high levels of contamination with Enterococcus spp. in 100 of all the samples (50 %). The highest resistance was recorded for a cream cheese sample, with resistance to 12 types of antibiotics. The lowest resistance was in a chicken sample, with resistance to 2 types of antibiotics. Only 4 strains were identified as vancomycin-resistant enterococcus (VRE), four of which were E. faecalis and originated from chicken. The results of this study underline the public health implications of VRE and the urgency about the preventive measures that must be taken to control the antibiotic use at farm level.     

Prevalence,enumeration, and characterization of Salmonella isolated from aquatic food products from retail markets in China

This study aimed to estimate the extent and level of Salmonella contamination of aquatic food products in China, and to determine serotype, virulotype, and the antimicrobial resistance profiles of recovered Salmonella isolates. Out of 554 samples collected from July 2011 to May 2014, 86 (15.5%) tested positive for Salmonella. The highest contamination rate occurred in oysters (23.1%, 6/26), followed by freshwater fish (18.6%, 43/231), shrimp (13.0%, 13/100), and saltwater fish (12.2%, 24/197). The contamination levels generally corresponded to a most probable number (MPN)/g of 0.3–10, although one sample exceeded 110 MPN/g. Among the 103 isolates, S. Typhimurium, S. Wandsworth, S. Thompson, and S. Derby were the most prevalent serovars. Sixty-eight isolates (66.0%) were resistant to at least one antimicrobial, and 35 (34.0%) were resistant to more than three. High rates of resistance were observed for tetracycline (35.9%), ampicillin (28.2%), nalidixic acid (26.2%), trimethoprim-sulfamethoxazole (25.2%), chloramphenicol (20.4%) and streptomycin (18.4%). Of note, S. Thompson isolates exhibited resistance to multiple extended-spectrum cephalosporins, ciprofloxacin, and other antimicrobials. PCR analysis of 15 virulence genes showed that ssaQ, mgtC, siiD, sopB, and bcfC were present in all 103 isolates, whereas the remaining loci were variably distributed. S. Typhimurium, S. Enteritidis, and S. Weltevreden isolates exhibited a wider range of pathogenicity determinants compared with the other strains. Our study provides a comprehensive surveillance on prevalence of Salmonella in aquatic food products from China and indicates its potential risk to public health. These data are valuable for epidemiological studies, risk management, and public health strategies.     

Occurrence and characteristics of Vibrio vulnificus in retail marine shrimp in China

Vibrio vulnificus is a gram-negative bacterium that naturally occurs in estuarine waters and marine environment. Consumption of seafood contaminated with V. vulnificus or exposure to the contaminated water causes septicemia, gastroenteritis or wound infections in humans. This study aimed at identifying the prevalence of V. vulnificus in shrimps in Chinese seafood market. From June to September 2009, 239 samples encompassing six shrimp species were collected from ten cities in China. To quantify the prevalence and the levels of V. vulnificus in shrimps, the most probable number (MPN) method was used combining with the polymerase chain reaction (PCR) which was used to classify the isolates by detecting V. vulnificus hemolysin gene (vvhA). One hundred and forty out of 239 samples were positive for V. vulnificus, with the geometric mean level at 153.3 MPN/g. The prevalence and levels of V. vulnificus in shrimps varied in different geographic areas, with the values for the samples in the South cities (179.6 MPN/g) remarkably higher than that in the North cities (7.6 MPN/g). In addition, we found that 61.7% (79/128) of the V. vulnificus positive samples contained C-type (Clinical) strains and 8 contained E-type (Environmental) strains. The antimicrobial susceptibility of the isolates to 12 antibiotics was tested as well. Most of the 169 isolates remained susceptible to the majority of antimicrobials tested, whereas some strains tend to be less sensitive to amikacin, ampicillin, tetracycline and gentamicin. In conclusion, V. vulnificus is commonly found in retail marine shrimp in Chinese seafood market, and most of the shrimp samples contained C-type strains, which may pose a potential threat to human health.     

Quantitative surveys of Salmonella and Campylobacter on retail raw chicken in Yangzhou,China

To assess the risks to consumers from Salmonella and Campylobacter in whole raw chickens sold in Yangzhou City, 12-month quantitative surveys were performed in succession. In this study, 480 samples were collected from supermarkets and wet markets from 2011 to 2013. The examination method of Salmonella was optimized from the most probable number (MPN), and the level of Campylobacter contamination was tested using the direct plating method. These results showed that the positive rates of Salmonella and Campylobacter were 33.8% and 51.3%, respectively, and the corresponding mean values of enumeration were 0.524 MPN/g and 1473.49 colony-forming units/g. For prevalence and loads of Salmonella, there was no significant difference between supermarkets and wet markets. However, for Campylobacter, the contamination level of wet markets was greater compared to supermarkets. Seasonality was observed in both qualitative and quantitative studies for both pathogens, with summer being the high-incidence season. Diversity among Salmonella isolates was high in terms of serovar, and the dominant serotypes were Salmonella Typhimurium (34.6%) and Salmonella Enteritidis (16.7%). Diversity of Campylobacter isolates demonstrated that Campylobacter jejuni (45.5%) and Campylobacter coli (30.9%) were the most common species, except for the mixed contamination. Survey results indicated that there was a need for more interventions to minimize the exposure of consumers to Salmonella and Campylobacter.     

Prevalence and quantification of Salmonella contamination in raw chicken carcasses at the retail in China

The quantitative contamination load of Salmonella in raw chicken carcasses at the retail level in six provinces and cities of China was determined within 1595 carcasses over 12 consecutive months. The overall Salmonella contamination rate was 41.6% and the median load of those contaminated was 4.6 MPN/100 g with 1.8 MPN/100 g as the 25th percentile and 18.0 MPN/100 g as the 75th percentile. There were significant variations in prevalence among carcasses sampled either in different provinces or sampling months. Carcasses collected in August had not only the highest prevalence of contamination (55.8%), but also the highest median (14.0 MPN/100 g) and 75th percentile load (120.0 MPN/100 g) values compared to January with lowest prevalence (26.5%), median (1.5 MPN/100 g) and 75th percentile load (7.6 MPN/100 g). The chilled (55.1%) stored carcasses was significantly higher in prevalence than those frozen (33.5%) and those freshly slaughtered (28.3%), those unpackaged (45.1%) was more likely to be contaminated with Salmonella than those packaged (37.4%). The present study revealed the widely prevalent Salmonella contamination among retail carcasses, indicating a strong potential of the cross-contamination occurred before and/or at the retail level. The study also provided quantitative data for a risk assessment evaluating potential intervention methods to reduce the risk of salmonellosis by consuming chicken meat of Chinese origin.     

Prevalence and characterization of Yersinia enterocolitica isolated from retail foods in China

Yersinia enterocolitica is an important food-borne enteropathogen that causes gastrointestinal syndromes. The aims of this study were to identify Y. enterocolitica in food samples in China, and to assess the pathogenic potential and antimicrobial resistance, and to characterize the genotypes of the isolates. From July 2011 to May 2014, a total of 2320 food samples were obtained, and 47 (2.03%) were found positive for Y. enterocolitica, while 706 retail-level ready-to-eat products and 249 vegetable samples were negative. A total of 58 Y. enterocolitica strains were isolated. All isolates belonged to biotype 1A, and the primary serotype was O:8. All strains lacked the ail, virF, ystA, and ystC virulence genes, but harbored the ystB, fepD, ymoA, fes, and sat genes. All 58 strains were sensitive to kanamycin and sulfonamide, but were resistant to two or more antibiotics. Most of the strains expressed the β-lactamase genes; the presence of blaA and blaB was detected in 97% and 100% of isolates, respectively. Many strains were resistant to trimethoprim/sulfamethoxazole (79.3%), ampicillin (91.4%), and cephalothin (91.4%). The 58 strains were grouped into three clusters and one singleton by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) at a similarity coefficient of 70%, and each cluster was largely organized by geographical region. This study provides a valuable accounting of the prevalence of Y. enterocolitica from a nationwide survey of foods in China, and highlights the seasonal effects of Y. enterocolitica prevalence in foods in China for the first time.     

Molecular screening and characterization of Shiga toxin-producing Escherichia coli in retail foods

Shiga toxin-producing Escherichia coli (STEC) strains are one of the most important recently emerged groups of food borne pathogens. This study investigated the prevalence of molecular markers for STEC and characteristics of E. coli O157 isolates from foods sold at retail markets in Wuhan, China. A total of 489 samples (350 meat products and 139 raw vegetables) were purchased from 22 large scale markets between July of 2011 and September of 2013. The meat samples consisted of frozen chicken products, raw pork, raw beef, frozen fish products and processed duck products. The raw vegetable samples consisted of lettuce, bok choy, radish, spinach, cucumber, and tomato. Shiga toxin genes (stx1 and stx2) and an O-group marker of the seven main pathogenic STEC serogroups (O157, O26, O45, O103, O111, O121, and O145) were detected in the samples by using PCR. 100% agreement was obtained between the results of the PCR targeting for wzy_O157 and the PCR targeting for rfbE_O157 gene. The result demonstrated that PCR assay targeting for wzy_O157 gene can be employed as an effective screening method for E. coli O157 in food sample. In the study, E. coli O157 and non-O157 STEC were detected in 55 (11.2%) and 75 (15.3%) samples by PCR screening, respectively. There was significant difference in the occurrence of STEC contamination between supermarkets (19/127, 15.0%) and open markets (111/362, 30.7%) (P < 0.05). Out of 489 samples, 5 samples carried O45, 1 sample carried O145 and 1 sample carried O111. Markers for O103, O26 and O121 were not detected. This result differed from other reports. Immunomagnetic separation based cultivation technique was used to isolate E. coli O157 from 27 food samples collected in 2013. Finally 7 E. coli O157 isolates were obtained. Among the 7 isolates, the prevalent stx genotype was stx_1a and stx_2a. Four E. coli O157 strains exhibited toxic effects on Vero cells, while 3 isolates had no detectable cytotoxicity effects even though they contained stx genes. All E. coli O157 isolates were sensitive to the 12 antimicrobials tested except for roxithromycin. There are some inconsistencies between the PCR screening and culture results. Characteristics of STEC isolates should be evaluated and considered for monitoring STEC contamination in foods.     

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.     

Ochratoxin A in Spanish retail ground roasted coffee: Occurrence and assessment of the exposure in Catalonia

Occurrence of ochratoxin A (OTA) in ground roasted coffee from different brands and types available in Spain was assessed. Based on these data, exposure of the Catalan population to OTA through coffee consumption was estimated. Coffee samples were purchased in hypermarkets and supermarkets of twelve cities of Catalonia, Spain, and composite samples were prepared for analysis. OTA was extracted, cleaned-up by immunoaffinity columns, and detected by HPLC-fluorescence detection. Mean OTA content (n = 72) was 2.17 ± 0.79 ng/g (range 1.21–4.21 ng/g, 49% occurrence). An additional sampling was done by brands (n = 45), mean OTA contamination being 2.07 ± 0.61 ng/g (range 1.30–5.24 ng/g, 95% occurrence). Coffee consumption data were obtained by means of a food frequency questionnaire. Mean coffee consumption per capita was 11.58 ± 8.73 g/person/day. OTA daily intake (DI) was estimated by means of deterministic and probabilistic methods. In both cases, estimated DI (around 0.22 ng/kg bw/day) was below the latest PTDI value of 17 ng/kg bw/day suggested by EFSA.     

Importance of eggshell cuticle composition and maturity for avoiding trans-shell Salmonella contamination in chicken eggs

The cuticle coating the eggshell surface is the first line of defense of the egg against bacterial ingress. However, the cuticle properties (i.e., thickness, degree of coverage, chemical composition) have a very large natural variability and this work analyzed how this variability influence the risk of eggs being contaminated by Salmonella. Microbial growth on the eggshell surface as well as the incidence of Salmonella penetration in eggs increases significantly with hen age for the groups (25, 35, and 52 weeks) considered in this study. It shows also that the cuticle is most effective against bacterial penetration between 6 and 72 h after eggs have being laid when this coating is fully mature and has not dried excessively. In contrast, freshly laid eggs can be easily contaminated as they have an immature cuticle which is not able to resist bacterial penetration. This study show also that the chemical composition of the mature cuticle determines the risk of trans-shell contamination by Salmonella. In particular, it shows that eggs with a cuticle rich in proteins have a decreased shell permeability and greater resistance against Salmonella penetration. The novel analytical technique used here to quantify the cuticle quality (based on infrared spectroscopy; ATR-FTIR) could be used in assisted selection programs aimed to improve the quality and safety of eggs.     

Prevalence and characterization of Listeria monocytogenes isolated from retail food in Henan,China

Listeria monocytogenes, an important foodborne pathogen, is the causal agent of listeriosis. In this study, a total of 954 food samples originating from raw meat, cooked meat products, seafood, and vegetables purchased from supermarkets and open-air markets in Henan province, China, were analyzed for the presence of L. monocytogenes. All L. monocytogenes isolates were subjected to serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial resistance. The overall percentage of L. monocytogenes prevalence was 6.2% (n = 59) with the highest rate of 7.4% for cooked meat products followed by raw meat (6.7%). The isolates belonged to five serotypes (1/2a, 1/2b, 1/2c, 4b, and 4c), with serotype 1/2a being predominant (55.9%). PFGE revealed a low genetic diversity among the isolates, irrespective of their sources, suggesting that dominant clones are widespread in different food products in Henan. Resistance to cefotaxime (30.5%) and ciprofloxacin (13.5%) was most often, whereas resistance to tetracycline, trimethoprim/sulfamethoxazole, and erythromycin was observed less frequently. The presence of L. monocytogenes in food products and antimicrobial resistance among the isolates represents a potential public health risk. Our results indicate that effective hygienic measures and bacteriological controls are necessary in China to reduce the contamination of retail food samples by L. monocytogenes.     

Prevalence,identification and molecular characterization of Cronobacter sakazakii isolated from retail meat products

Cronobacter sakazakii is an opportunistic foodborne pathogen predominantly in neonates with reported incidences in adults especially immunocompromised and the elderly. The current study was carried out to determine the prevalence of these organisms on meat products sold at Mansoura city, Egypt; besides its ability to compete with E. coli O157:H7 and Salmonella on their media. Suspected colonies were phenotypically-identified using API 20E system, additional biochemical tests, besides production of yellow-pigmented colonies; and genotypically-identified using species-specific PCR assays to detect the gene responsible for α-glucosidase activity, 16S rRNA gene and internal transcriber spacer sequence between 16S and 23S rRNA. Out of the 93 tested isolates, 14 isolates were confirmed as C. sakazakii with contamination rates of 16% (8/50) and 15% (6/40) of ground beef and beef burger samples, respectively and overall contamination rate of 15.6% (14/90) of all tested samples. The isolates were distributed among 7 different biogroups. These results added new epidemiological evidence about the widespread occurrence of these pathogens on tested meat products and such occurrence is an indicator for potential contamination with pathogens and so a health risk for consumers. Furthermore, C. sakazakii is an important competitor to E. coli O157:H7 and Salmonella on their selective media.     

Salmonella prevalence associated with chicken parts with and without skin from retail establishments in Atlanta metropolitan area,Georgia

The objective of this study was to determine Salmonella prevalence in chicken parts with and without skin collected from retail establishments in Atlanta metropolitan area (Georgia, USA). Retail packs (n = 525) of cut-up chicken parts (i.e., breasts and thighs with skin-on and skin-off, and drumsticks with skin-on) were collected from supermarket stores in five counties in Atlanta metropolitan area. The skin-on and skin-off retail chicken packs by part type were paired by production company, plant numbers, and sell-by date. The skin from skin-on parts was removed and analyzed for presence of Salmonella; whereas the top layer of meat from skin-off parts was removed and analyzed for this pathogen. Additionally, Salmonella isolates were genotypically characterized. Salmonella prevalence in the skin of chicken breasts (44.7%) was significantly (P < 0.05) higher than in the meat (12.3%) of skin-off breast samples. Similarly, the prevalence was significantly (P < 0.05) higher in the skin of chicken thighs (40.9%) than that in the meat of skin-off thighs (22.8%). Salmonella prevalence in skin of drumsticks was 41%. Among the 117 isolates characterized, eight Salmonella serotypes were identified including Heidelberg (46.1%), Kentucky (26.4%), Typhimurium (11.1%), Infantis (5.1%), Seftenberg (2.5%), and Thompson (0.8%). High clonality of Salmonella isolates within and between chicken part type was observed. Skin-on chicken part may act as a greater source of Salmonella transmission to consumers compared to skin-off chicken parts.     

Prevalence,molecular identification and antimicrobial resistance profile of Salmonella serovars isolated from retail beef products in Mansoura,Egypt

The present study was undertaken to determine the prevalence of Salmonella in 270 raw meat samples (90 each of fresh beef, ground beef, and beef burger) purchased on nine occasions from various supermarkets and butchers' shops in Mansoura city, Egypt. Using conventional biochemical identification, Salmonella species were recovered from 23.3% (21/90), 20% (18/90), and 12.2% (11/90) of fresh beef, ground beef and beef burger samples, respectively with an overall prevalence of 18.5% (50/270) among all the meat products examined. Higher prevalence were obtained based on molecular identification, by detecting gyrB and invA genes, which verified the presence of Salmonella species in 30.0% (27/90), 26.7% (24/90), and 16.7% (15/90) of fresh beef, ground beef, and beef burger samples, respectively with an overall prevalence of 24.4% (66/270) among all the meat products tested. Of the 2635 presumptive colonies tested, 228 were biochemically identified as Salmonella, while 272 were molecularly identified as Salmonella, which were all positive for the enterotoxin (stn) virulent gene. Of the 272 serologically tested strains, 266 were serologically identified into six Salmonella serovars, while 6 strains were untypable. Salmonella Typhimurium and Salmonella Enteritidis were the most prevalent serovars with an incidence of 38.2% (104/272) and 34.6% (94/272), respectively. The other four serovars identified were Salmonella Haifa, Salmonella Muenster, Salmonella Virchow, and Salmonella Anatum were detected at lower prevalences of 11% (30/272), 7.4% (20/272), 4% (11/272) and 2.6% (7/272), respectively. Interestingly, the antimicrobial susceptibility testing indicated that all of the 100 Salmonella serovars tested were multidrug resistant (resistant to three or more antibiotics). Our findings demonstrated that the retail beef products tested were widely contaminated with multidrug-resistant Salmonella and such contamination may constitute a major public health concern.     

Occurrence of Salmonella spp. in persimmon fruit (Diospyrus kaki) and growth of Salmonella enteritidis on the peel and in the pulp of this fruit

The occurrence of Salmonella spp. on persimmon (Diospyrus kaki) surface of ‘Fuyu’ and ‘Rama Forte’ was evaluated during a 5-month-period (from April to August) of two season periods (years 2005 and 2006). The fruits were collected in wholesale (CEAGESP) and street markets in Sao Paulo and Campinas City, Brazil. A total of 582 fruits were analyzed using the BAX^® system, which is based on the Polymerase Chain Reaction (PCR). The ability of this pathogen to grow on the peel and pulp of the two persimmon varieties was also verified at different incubation periods at temperatures of 10, 20 and 30 °C. The growth parameters were obtained by modeling the experimental data using the Gompertz function. The presence of Salmonella spp. was evidenced in 5 of the 582 analyzed fruits (0.9% incidence). The growth studies showed that Salmonella enteritidis can grow on the peel as well as in the pulp of the two persimmon varieties studied incubated at 10, 20 and 30 °C and that low temperatures can reduce the generation rate but do not inhibit its growth.     

Prevalence of Salmonella in raw minced meat,raw fresh sausages and raw burger patties from retail outlets in Gaborone,Botswana

The prevalence of Salmonella in raw minced meat, raw burger patties and raw fresh sausages was determined by analysing 122 minced meat, 120 sausages and 58 burger patties obtained from retail outlets in Gaborone, Botswana. The prevalence rate was 20%. The most prevalent serogroups were B, followed by C and E/G. The Salmonella enterica serovars isolated were S. Typhi, S. Enteritidis, S. Anatum, S. Reading, S. Melagridis, S. Typhimurium, S. Paratyphi B, S. Newport, S. Bovis-morbificans, S. Braenderup, S. Infantis, S. Tennessee and S. Montevideo. The presence of S. Typhi and Paratyphi in meat products indicate human origin and therefore poor personal hygiene during handling of the meat products. Multidrug resistance patterns involving sulphatriad, sulphafurazole, tetracycline and cotrimoxazole were observed. Isolates in serogroups B and C were resistant to a greater number of antibiotics than isolates from other serogroups.     

Occurrence of Listeria monocytogenes and Salmonella spp. in meat processed products from industrial plants in Southern Italy

The main goal of the present investigation was to assess the microbiological safety of two typical meat-derived products, i.e. raw pork sausages and entrails lamb rolls, produced in Salento (Apulia, Southern Italy). Analyses were carried out for 7 years (from 2008 to 2014) and a total number of 6720 samples was collected by specialized personnel. The presence of Listeria monocytogenes and Salmonella spp. was detected by a PCR-based assay, combined with culturing in enrichment broth. The prevalence of L. monocytogenes was assessed in 2.4% entrails lamb rolls and in 4.2% raw pork sausages samples, whereas the occurrence of Salmonella spp. was revealed in 2.7% lamb rolls and in 3.5% pork sausages. A statistically significant seasonal variation was found in the occurrence of L. monocytogenes; in fact a higher number of samples contaminated by this pathogen was recorded in spring and autumn. On the contrary, no significant seasonal changes occurred in the prevalence of Salmonella spp. The data reported indicate that, due to the presence of these pathogens, the Italian food processors need to improve the microbiological monitoring of the processing chains, in order to guarantee health safety.