Microbial profile and antibiotic susceptibility of Campylobacter spp. and Salmonella spp. in broilers processed in air-chilled and immersion-chilled environments

Carcass chilling is considered a critical step for inhibiting bacterial growth during poultry processing. The objective of this study was to compare microbiological loads and the incidence of Salmonella spp. and Campylobacter spp. on broiler carcasses subjected to immersion chilling and air chilling. Additionally, the antibiotic resistance patterns of pathogen isolates were determined. The results of this study indicated that the incidence of Salmonella spp. and Campylobacter spp. tends to be significantly lower in air-chilled broilers, suggesting that cross-contamination may be more prevalent for immersion-chilled broilers. No significant differences were detected between chilling treatments for total aerobic populations or for generic E. coli or coliform counts. Psychrotrophic populations were significantly larger (P < 0.05) in immersion-chilled broilers than in their air-chilled counterparts. Campylobacter isolates from immersion-chilled broilers had a higher incidence of resistance to nalidixic acid (NAL) and related fluoroquinolones than isolates from air-chilled broilers did. Additionally, Campylobacter isolates from air-chilled broilers had a higher frequency of resistance to tetracycline than isolates from immersion-chilled broilers did. With regard to Salmonella, isolates from immersion-chilled broilers had a higher incidence of resistance to NAL than isolates from air-chilled samples did. No Salmonella isolates from immersion- or air-chilled broilers were resistant to the fluoroquinolones tested. The chilling method used during processing may influence the microbial profile of postchilled broilers.     

Microbiological water quality requirements for salad irrigation in the United Kingdom

The growth in United Kingdom salad production is dependent on irrigation to maintain product quality. There are concerns that irrigation with poor-quality water could pose a disease risk. This article examines the key issues in the emerging debate on the microbiological quality of water used for salad irrigation in the United Kingdom. The links between irrigation water quality and foodborne disease, and the current international guidance on irrigation water quality, are firstly reviewed. The findings indicate that a number of recent food-poisoning outbreaks have been linked to the consumption of fresh fruits and vegetables and that unhygienic product handling is implicated as the principal source of contamination. There is also credible evidence that salads contaminated in the field, including by irrigation water, can pose a small disease risk at the point of sale. Although irrigation water-quality standards exist in various forms internationally, there is no nationally agreed on standard used in the United Kingdom. This paper then describes the results of a survey conducted in 2003 of United Kingdom irrigation practices that might influence the microbiological quality of salads. The survey showed that surface water is the principal irrigation water source, that overhead irrigation predominates, that the gap between the last irrigation and harvest may be < 24 h in many cases, and that current water-quality monitoring practices are generally very limited in scope. This paper concludes with a discussion of the issues emerging from the review and survey, including the need for improved water-quality monitoring, and the problems associated with establishing water-quality standards that could be either too strict or too lax.     

Microbiological quality of Australian beef

A survey of the microbiological quality of beef carcasses and boneless beef produced in Australia was conducted during the period June to November 1998. Sponge samples were collected from 1,275 carcasses, and meat samples were drilled from 990 cartons of frozen boneless beef. Carcass and boneless beef samples were respectively collected from 21 and 27 establishments that concentrated on export and from 38 and 3 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering no more than 150 cattle equivalents per week. The mean log total viable counts (TVCs) were 2.42/cm2 and 2.52/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 10.3% of carcasses and 5.1% of boneless beef samples and coagulase-positive staphylococci on 24.3% of carcasses and 17.5% of boneless beef. Salmonella was detected on 0.2% of carcasses and 0.1% of boneless beef and E. coli O157:H7 recovered from 0.1% of carcasses but not detected on 990 boneless beef samples. Mean log TVCs/cm2 differed significantly (P < 0.05) between establishment types. They were lower on carcasses from export establishments (2.20) compared with domestic (2.61) and very small plants (3.10). There were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. Excision samples were taken from 670 carcasses to make comparisons with the first baseline study of Australian meat, carried out in 1993 to 1994. While there were differences in sampling and microbiological techniques between the two studies that require detailed consideration, there were small but significant improvements in several microbiological criteria for carcasses and boneless meat.     

Microbiological quality of rabbit meat

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01 +/- 0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P < 0.05) than that (4.96 +/- 0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 +/- 0.18) stored at -1 to +1 degree C (supermarket 1), mean aerobic mesophilic count was 5.87 +/- 1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 +/- 0.18) displayed at -1 to +5 degrees C (supermarket 2), mean aerobic mesophilic count was 6.60 +/- 1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 > large abattoir > supermarket 1 > small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.     

Microbiological quality of artisanal Sepet cheese

Microbial diversity in milk and in cheese itself affects the biochemical and sensory characteristics of artisanal cheeses. In this study, the microflora of Sepet cheese, which is a traditional artisanal cheese in Turkey, was investigated. Average lactococci, lactobacilli, enterococci, yeast, mould, coliform, psychrotrophic and total aerobic bacteria, presumptive Staphylococcus aureus counts were; 7.31 ± 1.08, 7.19 ± 1.02, 6.84 ± 0.92, 3.19 ± 1.40, 0.84 ± 0.89, 2.18 ± 1.81, 4.92 ± 1.15, 7.53 ± 1.13 and 1.25 ± 1.70 log cfu/g, respectively. Staphylococci, coliform and mould counts were less than 1.00 log cfu/g at the end of ripening, which was at around 6–8 °C for 3 months. According to phenotypic and genotypic identifications, isolates were closely related to Lactobacillus plantarum, Weisella confusa, Weisella paramesenteroides, Pediococcus pentasaceous, Enterococcus casseliflavus, Enterococcus durans and Enterococcus faceium. This study provides baseline data on the microflora of traditional artisanal Sepet cheese, which is a prerequisite for a successful scale up to industrial production.     

Microbiological quality of fresh-cut sweet potatoes

Sweet potato roots were dipped in various concentrations of chlorine for 5 min at 1 or 20 °C before and after slicing, and then stored at 2 or 8 °C for 14 days to evaluate the effects of different chlorine treatments and storage temperatures on the microbiological quality of fresh‐cut sweet potato slices. The microflora of fresh‐cut sweet potato slices was dominated by mesophiles, followed by psychrotrophs and fungi initially and during storage. The 2 °C storage was necessary to keep the microbial load at a low level. No spoilage was observed in fresh‐cut sweet potatoes at both storage temperatures for 14 days. Chlorination of sweet potatoes before slicing was not effective in ensuring acceptable microbiological quality of fresh‐cut sweet potatoes. Dipping slices in 200 ppm chlorine at 1 °C reduced the population of all micro‐organisms during storage.     

Microbiological quality of Australian sheep meat

Microbiological quality of sheep carcasses and boneless sheep meat produced in Australia was surveyed during the period June to November 1998. Sponge samples were collected from 917 carcasses, and meat samples were drilled from 467 cartons of frozen boneless meat. Carcass and boneless meat samples were respectively collected from 7 and 10 establishments that concentrated on export, and from 36 and 5 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering cattle and sheep but no more than 1,200 sheep equivalents per week. The mean log total viable counts were 3.55/cm2 and 3.30/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 29.2% of carcasses and 24.5% of boneless meat samples and coagulase-positive staphylococci on 24.1% of carcasses, and 38.6% of boneless meat samples. Salmonella was detected on 0.1% of carcasses and 1.3% of boneless meat samples. E. coli O157:H7 was recovered from 0.7% of carcasses and 1.3% of boneless sheep meat. There were statistically significant differences between establishment types for some microbiological criteria, although there were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. While there were differences in sampling and microbiological techniques between this study and another conducted in 1993 to 1994 that require detailed consideration, there were small but significant improvements in several microbiological criteria for boneless meat. While data that would allow for comparison of carcass data were not gathered, it is unlikely that improvements in the microbiological quality of boneless sheep meat could accrue without improvements to carcasses.     

Microbiological and biochemical quality of grouper (Epinephelus chlorostigma) stored in dry ice and water ice

The changes in the microbiological and biochemical quality of grouper (Epinephelus chlorostigma) stored in dry ice (solid carbon dioxide) were investigated. Fresh fish stored in dry ice at the ratio of 1:1 (wt/wt) were found to be organoleptically suitable for consumption when they were stored for 30 h without re‐icing. Fish stored in water ice (as control) at the ratio of 1:1 (wt/wt) and in a combination of dry ice and water ice at the ratio of 1:0.2:0.5 (wt/wt/wt) were acceptable up to 18 and 24 h, respectively. Total bacterial load ranged from 10⁵ to 10⁷ CFU g^?1, while total psychrophiles from 10³ to 10⁶ CFU g^?1. Total lactics were found in the levels of 10²–10⁴ CFU g^?1. Total volatile basic nitrogen contents were within the limit of acceptability in all the three treatments, whereas trimethylamine nitrogen content exceeded the limit (15 mg%) and hypoxanthine content was 11.11 mg (100 g)^?1 on the 30 h in grouper stored only in dry ice. Lowest temperature of ?5.8 °C was recorded in grouper stored only in dry ice. Hundred percent CO₂ environment within the package was found in grouper that were stored in dry ice and combination of dry ice and water ice.     

Microbiological quality of frozen raw and cooked shrimps

The microbiological quality of frozen raw and cooked shrimps destined for import and export was determined. The total number of frozen shrimp samples tested were 657 comprising 54 (FW) freshwater shell-on, 29 freshwater peeled deveined, 123 seawater (SW) shell-on, 410 seawater peeled deveined, and 41 seawater cooked. The geometric means for APC g⁻¹, coliform counts (MPN g⁻¹) and E. coli counts (MPN g⁻¹) were, respectively, FW shell-on, 890 000, 82 and 14; FW peeled deveined, 430 000, 16 and 5; SW shell-on, 310 000, 10 and 3; SW peeled deveined, 410 000, 9 and 3 and seawater cooked 7000, 4 and 3. 653 (99%) of the samples had S. aureus counts of less than 50 MPN g⁻¹. Shigella and Vibrio cholerae were not detected and Salmonella was positive for 3 (0·5%) of the 657 samples tested.     

Microbiological quality and shelf life modeling of ready-to-eat cicorino

Growth of the microbial population resident in ready-to-use fresh cut cicorino, a variety of Chichorium intybus, was determined in the various preparation steps with the aim of defining the hazard critical control points. The investigation concerned cut cicorino from two producers. During the process a 1- to 1.5-fold increase of microbial counts was observed, and the retail product showed values of 10(5) to 10(6) CFU/g. The shelf life of the product was kinetically modeled in order to check the effects of storage temperature and assess the microbial indexes most relevant for hygiene and quality of the distributed product. A modified Gompertz function described the kinetics of microbial growth and allowed definition of a stability time and its dependence on temperature. Stability times were of 0.3, 3.7, and 4.7 days at storage temperatures of 20, 10, and 5 degrees C, respectively. Q10 (the fold decrease of stability time for an increase of 10 degrees C) was 3.85. The results from this study may be used to predict the effects of temperatures experienced in the distribution chain on bacterial levels in cicorino.     

Microbiological quality of sushi from sushi bars and retailers

Sushi is a traditional Japanese food, mostly consisting of rice and raw fish. Fish is considered a healthy food, but as with other animal products, consumption of raw muscle incurs potential health risks such as ingestion of pathogenic bacteria or parasites. In this study, 250 sushi samples were analyzed for their microbiological status and the prevalence of pathogenic bacteria. A comparison was made between frozen sushi from supermarkets and fresh sushi from sushi bars. Aerobic mesophilic bacteria counts differed for sushi from these two sources, with means of 2.7 log CFU/g for frozen sushi and 6.3 log CFU/g for fresh sushi. The prevalence of Escherichia coli and Staphylococcus aureus was higher in the fresh samples. Salmonella was found in four (1.6%) of the sushi samples, and Listeria monocytogenes was found in three (1.2%) of the samples. These results indicate that the microbiological quality of industrially processed sushi is higher than that of freshly prepared sushi. The quality of freshly prepared sushi strongly depends on the skills and habits of the preparation cooks, which may vary.     

Microbiological and sensory quality of sonicated calcium-added orange juice

Ultrasonic treatments were applied at a frequency of 20 kHz and three wave amplitudes for 2, 4, 6, 8 and 10 min, to orange juice with added calcium. Aerobic mesophilic count (AMC), yeast and mold counts (YMC), Hunter color values, ascorbic acid concentration and sensory attributes were measured. Wave amplitude of 89.25 μm for 8 min was selected for final treatment of the juice, and storage studies were performed at 4 and 10 °C. Microbial inactivation followed Geeraerd, Herremans, and Van Impe (2000) model. The treatment decreased AMC by 1.38 log CFU/ml, and YMC by 0.56 log CFU/ml. The sensory quality of the juice was slightly deteriorated after treatment, but during storage, it degraded faster for controls than for treated samples. Controls were rejected by the sensory panel after 6 days storage at 4 °C due to off-flavor, and ultrasonicated juice after 10 days due to off-odor. Consequently, a shelf-life extension of 4 days was achieved. At both times (6 or 10 days) AMC reached 6.5 log CFU/ml, which suggests a relation between sensory deterioration and bacterial activity. Sonication also affected color and decreased ascorbic acid content. This study shows that ultrasonication may be useful to extend the shelf-life of orange juice.     

Microbiological quality and shelf life prediction of chilled fish

A number of storage experiments have been carried out with whole cod and vacuum-packed cod fillets stored in ice. The microbiological quality of the fish was determined on the basis of detection time estimated rapidly by conductance assays in a TMAO-containing medium at 25 degrees C. Detection time and sensory data have been incorporated into a predictive linear model to estimate the remaining shelf life of the products. It is concluded that the shelf life of iced whole cod can be predicted using this model but not that of vacuum-packed fillets because of the greater variability of bacterial activity in packaged fish.     

Microbiological quality of foods packaged under modified atmospheres

The microbiological quality of various sandwiches and meats packaged under modified atmosphere was evaluated. Samples were analyzed both on the day of manufacture and at the end of shelf life. On day 0, around 60% of products examined contained ≤10⁵ total aerobic counts g⁻¹, while at the end of the shelf life approximately 63·3% of samples contained ≥10⁷ cfu g⁻¹.Listeria spp. were found in eight of the 58 lots examined, withL. monocytogenes being present in five of the eight samples. One lot was found to containAeromonas hydrophila, while another one containedStaphylococcus aureus. Clostridium botulinum andSalmonella spp. were not found in any of the samples.     

Microbiological quality of white-brined cheeses: a review

White-brined cheeses are widely produced in the North-east Mediterranean area and the Balkans. Traditionally, they were manufactured as artisanal cheeses, and nowadays they are manufactured on an industrial scale, and rigorous control of the production and maturation processes is essential. Aspects of the microbiology of white-brined cheeses and their significance with respect to the quality and safety of the final products are discussed in this review.     

Microbiological quality of ice used to refrigerate foods

Ice used for human consumption or to refrigerate foods can be contaminated with pathogenic microorganisms and may become a vehicle for human infection. To evaluate the microbiological content of commercial ice and ice used to refrigerate fish and seafood, 60 ice samples collected at six different retail points in the city of Araraquara, SP, Brazil, were studied. The following parameters were determined: total plate counts (37°C and 4°C), most probable number (MPN) for total coliforms, fecal coliforms and Escherichia coli, presence of Salmonella spp., Shigella spp.,Yersinia spp., E. coli, Vibrio cholerae and Aeromonas spp.. Results suggested poor hygienic conditions of ice production due to the presence of indicator micro-organisms. Fifty strains of E. coli of different serotypes, as well as one Y. enterocolitica biotype 1, serogroup O:5, 27 and phage type Xz (Ye 1/O5,27/Xz) and oneSalmonella Enteritidis phage type 1 (PT1) were isolated. Aeromonas spp., Shigella spp. and V. cholerae were not detected. The presence of high numbers of coliforms, heterotrophic indicator micro-organisms and pathogenic strains suggested that commercial ice and ice used to refrigerate fish and seafood may represent a potential hazard to the consumer in our community.     

Microbiological quality of retail chicken by-products in Spain

The microbiological quality of retail chicken parts (legs, wings and giblets) and processed chicken products (hamburgers and sausages) in Spain was investigated. Mean counts (log(10) cfu/g) ranged from 5.56 to 7.28, 5.96 to 7.87, 3.49 to 5.42, 2.60 to 4.33 and 2.47 to 3.48 for mesophiles, psychrotrophs, coliforms, Escherichia coli and Staphylococcus aureus, respectively. Chicken parts were generally regarded as being of unacceptable quality, since psychrotrophs, E. coli and S. aureus counts were higher than the maximum limits established in the guidelines for poultry meat. On the basis of Spanish Microbiological Standards, 80% of the samples of hamburgers and sausages were also regarded as being of unacceptable quality. The main reason for the lack of acceptability was excessive counts of mesophiles. The results in this study indicate that chicken by-products (especially those made with ground meat) could represent notable hazards to humans and are a cause of public health concern.     

Microbiological quality of some retail spices in India

A total of 154 samples of 27 kinds of spices from retail shops of 20 States of India was investigated to determine their microbial status. As per ICMSF specifications, the total aerobic mesophilic bacteria (TAMB) count showed that 51% of the samples were in the unacceptable level (>10⁶ cfu g⁻¹). While moulds were detected in 97% of the samples, yeast was found in only one. Bacillus cereus, Clostridium perfringens, Staphylococcus aureus and members of Enterobacteriaceae occurred in 85, 59, 11 and 85%, respectively of the kinds. Whereas black pepper powder, caraway, garlic and red chilli did not contain B. cereus, this foodborne pathogen was found in all the samples of ajmud, small cardamom and cumin powder. Coliforms and faecal coliforms were found in 33 and 15%, respectively of the kinds. Escherichia coli was detected in only one sample, of garlic. Salmonella and Shigella were found only in 2.6% of the samples. Although they contained less TAMB, the non-packaged spices had a higher load of moulds, B. cereus and Enterobacteriaceae than that of polyethylene-packaged ones.