High nutritional content coupled with low cost and ease of purchase justifies the frequent use of chicken eggs. Even with technological innovations in the production, storage, and distribution of eggs, food poisoning continues to occur. Therefore, in the present study, we 1) evaluated the microbiological profile and the hygienic and sanitary quality of eggs commercialized in town fairs and markets and 2) verified whether there is any correlation between microbiological results and commercialization conditions. Thirty-six samples were collected from six municipalities in the region of Recôncavo from Bahia, Brazil. The hygienic and sanitary conditions were analyzed by quantifying the total coliforms, E. coli, mesophilic and psychrotrophic microorganisms, molds, and yeasts, and by the presence of Salmonella sp. The observational analysis showed that 91% and 68% of the samples in town fairs and markets, respectively, did not comply with the requirements of the current Brazilian legislation. There was no significant difference in the microbiological profile among samples from the fairs and markets. Several samples presented relevant significant values, indicating inadequate hygienic conditions and fecal contamination. Salmonella sp. was found in one sample. There was co-relationship between microorganism count and the variables “external dirt”, “external stains”, and “closeness to other products”, with high concentrations of total coliforms and E. coli in the non-conforming samples. Although no limits exist for mold and yeast counts, the presence of fungi makes the product unfit for consumption. Thus, the commercialization of eggs would benefit from more attention and supervision by the relevant authorities.
Eggs are perhaps the most nutritious food in nature, as they represent a low-cost source of high protein contents. However, worldwide epidemiological data have shown that they may also be a source of Salmonella, causing infections in human [
Considering the foods that caused disease outbreaks in Brazil between 2007 and 2016, eggs and egg-based products ranked third, behind only to mixed food and water [
Pathogens recovered from eggs in the past included the following species: Aeromonas, Campylobacter, Listeria, and Salmonella. However, in terms of reported outbreaks of illness attributed to eggs, only Salmonella is of significance.
Considering that there are only a few studies in Brazil on pathogenic microorganisms and microbiological characterization in eggs, the objective of the present study was to evaluate the microbiological profile of eggs commercialized in public fairs and markets in the municipalities of Recôncavo from Bahia region, Brazil.
The present analysis was carried out between December 2015 and January 2016, and encompassed six municipalities in the Recôncavo da Bahia Region, Brazil: Nazaré, Santo Antônio de Jesus, Cachoeira, Santo Amaro, Cruz das Almas, and São Felipe (39˚06'26"S latitude and 12˚40'39"W longitude, with an altitude of 226 m). Three market suppliers and three town fair suppliers from the above mentioned towns were selected for egg collection. Samples were purchased and each sample unit comprised six eggs per selling firm; a total of 36 samples from 18 markets and 18 fairs.
An observational analysis was performed upon the retrieval of egg samples. This employed a verification list based on Decrees RDC No. 275/2002, RDC No. 216/2004, and RDC No. 35/2009, defining hygienic and sanitary conditions for the commercialization site, eggs, and handlers. These laws emphasize the use of the guidelines that compose the standards of good food manufacturing practices, such as standards of good practices for food services, as well as mandatory maintenance and consumption instructions for egg labeling [
The percent of commercial sites complying or not complying with the above Decrees was identified based on the data obtained from the verification list. A correlation study between the results of observational and microbiological analyses was performed.
The samples were prepared as described by Silva et al. [
Although the eggshell is an important source of bacterial contamination, it was not analyzed due to limited diagnostic resources.
The protocol was made with six replicates.
The total coliform and E. coli counts were determined by the pour plate technique, using HiCrome Coliform Agar culture medium (HiMedia). One microliter of sample was diluted on Petri plates and approximately 15 mL of medium was added. The mixture was homogenized and after solidification, the plates were inverted and incubated at 35˚C for 24 h [
The pour plate technique was employed to count mesophilic and psychrotrophic microorganisms on Plate Count Agar medium (Merck). Briefly, 1 mL of sample was transferred to Petri plates, medium was added, and the mixture was homogenized. After solidification, the plates were inverted and incubated in a buffer at 35˚C for 48 h to allow the growth of mesophilic bacteria. The plates were then maintained in a refrigerator (4˚C) for seven days to allow the growth of psychrotrophic microorganisms. The colonies were counted [
The molds and yeasts were counted by the spread plaque technique: 0.1 mL of each diluted sample was transferred to Petri plates containing amalgamated and solidified Agar Sabouraud Dextrose culture medium (Merck), and spread with a sterile Drigalski spatula. The plates were then inverted and incubated at 20˚C under biochemical oxygen demand conditions for five days. The colonies were counted [
The 3M Petrifilm Salmonella Express system was employed to detect Salmonella. First, 25 g of egg sample was weighed and transferred to 225 mL of enriched broth prepared with Enrichment Base 3M Salmonella Express. The Supplement 3M Salmonella Express was homogenized and incubated at 41.5˚C for 18 h. After incubation, 10 µL of the samples were spread with an inoculation spatula onto Petrifilm plates previously hydrated with 2 mL of distilled water. The plates were again incubated at 41.5˚C for 24 h, and then the presumed Salmonella spp. colonies adhering directly to the film were read. The colony color ranged between red and brown, and included a yellow zone, gas bubbles, or both. The plates featuring colonies with the above characteristics were covered with a biochemical disc to confirm the presence of Salmonella spp. They were again incubated at 41.5˚C for 4 h. A change from reddish-brown to a green-bluish hue, dark blue, or black indicated that the colonies were not Salmonella spp. The results are expressed as presence or absence of Salmonella spp.
The results were analyzed in accordance with the microbiological standards for food of animal origin that necessitates the absence of Salmonella spp. in a sample of 25 g for it to be considered safe [
The SPSS software (SPSS Statistics for Windows, version 17.0; SPSS Inc., Chicago, IL) was employed for the statistical analysis. The descriptive analysis of microorganism counts and proportion analysis of qualitative variables, or rather, the results of the Salmonella test and the verification list, were performed. Student’s t-test compared the microbiological profile of the eggs according to the commercialization site (town fairs and markets) and correlated the concentration of microorganisms with the variables in the verification list.
The continuous variables are expressed as mean ± standard deviation (SD), and the cut-off point for the p-value was 0.5% (level of statistical significance is p < 0.05).
The results of microbiological analyses did not show any statistical difference with regard to the commercialization site. Although the mean rate of total coliforms
Microorganism | Public fairs log CFU g−1 | Markets log CFU g−1 | p | ||||
---|---|---|---|---|---|---|---|
MIN | MAX | M | MIN | MAX | M | ||
Total coliforms | <1.0 | 4.72 | 1.85 ± 1.19 | <1.0 | 4.52 | 1.75 ± 1.62 | 0.83 |
Escherichia coli | <1.0 | 3.70 | 1.33 ± 0.89 | <1.0 | 3.48 | 1.32 ± 1.10 | 0.96 |
Mesophiles | <1.0 | 6.48 | 3.59 ± 1.69 | 1.48 | 7.12 | 3.40 ± 1.59 | 0.72 |
Psychrotrophs | <1.0 | 3.60 | 1.85 ± 0.91 | <1.0 | 4.00 | 1.89 ± 1.01 | 0.88 |
Molds and yeasts | <1.0 | 6.60 | 3.76 ± 1.86 | <1.0 | 7.20 | 3.31 ± 2.08 | 0.50 |
Presence | Presence | ||||||
Salmonella | 1 (2%) | 0 |
MIN, minimum rate in samples; MAX, maximum rate in samples; M, mean rate for municipalities; SD, standard deviation. Data are considered significant at p < 0.05.
was not very high, several samples reached the maximum rate, corresponding to 4.72 log CFU g−1 in town fairs. According to Franco and Landgraf [
In the present study, the mean E. coli counts were low, ranging between <1.0 and 3.70 log CFU g−1. The amount of thermotolerant coliforms, represented mainly by E. coli, indicated fecal contamination [
Although there were no significant differences in the rate of psychrotrophic microorganisms among the samples obtained from town fairs and markets, the maximum rates indicated high levels in some samples. The psychrotrophic microorganisms indicate the general contamination of a product, level of hygiene employed during handling and storage, and conservation period [
In the present study, the count of molds and yeast in samples from town fairs and markets was 3.76 and 3.31 log CFU g−1, respectively. The Decree No. 1/1990 specifies general norms for egg inspection and derivatives, and classifies eggs contaminated with fungi on the exterior and interior as unfit for consumption. Accordingly, these eggs are not safe for consumption and should not be sold [
Bacteria and fungi are the main microorganisms responsible for the physical and chemical changes observed in eggs. An assessment of the internal quality attributes of eggs associated with the storage form is indispensable; after oviposition, eggs inevitably begin to undergo structural changes, which can lead to the loss of quality and eventually deterioration. The reduction of contamination of equipment and facilities in farms can reduce bacterial contamination in final production of eggs by 80%. In this scenario, the presence of airborne fungi even with the adoption of Good Manufacturing Practices (GMPs) during egg production indicates the need for monitoring air quality in industries and greater selection and quality control of eggs coming from selected farms [
In the present study, among the samples analyzed for Salmonella sp., only one sample (3%) did not comply with the national standards [
According to a survey by Rossi and Bampi [
Only one (5%) fair presented at least one egg with cracks or a broken shell.
Indicator | Town fairs (n = 18) | Markets (n = 18) | ||||
---|---|---|---|---|---|---|
%C | %NC | %C | %NC | |||
Cracks/broken shell | 94 | 5.6 | 83 | 17 | ||
External dirt | 6 | 94 | 11 | 89 | ||
External stains | 0 | 100 | 11 | 89 | ||
Packaging | 0 | 100 | 94 | 6 | ||
Place of shelf | 0 | 100 | 0 | 100 | ||
Refrigeration | 0 | 100 | 0 | 100 | ||
Closeness to other products | 0 | 100 | 17 | 83 | ||
Expiration date | 0 | 100 | 17 | 83 | ||
Mandatory information on packaging: “The consumption of this product in the raw or undercooked state may be harmful to health” | 0 | 100 | 22 | 78 | ||
Mandatory information on package: “Keep eggs under refrigeration” | 0 | 100 | 17 | 83 | ||
Inspection label | 0 | 100 | 11 | 89 | ||
Presence of vectors and pests | 78 | 22 | 94 | 6 | ||
Personal hygiene | 0 | 100 | NA | |||
Simultaneous handling of money and food | 0 | 100 | NA | |||
Total in each site (%) | 9 | 92 | 32 | 69 | ||
C, conformity with the law; NC, non-conformity with the law; NA, not applicable.
Most commercialized eggs were intact, or rather, without any cracks. Markets had a 16% non-conformity rate with regard to this criterion. Pascoal et al. [
A high percent of eggs at town fairs and markets has been reported to be stained and contain external dirt. According to Barros et al. [
No fair passed the conformity test with regard to the packaging in which the eggs were commercialized. The eggs were sold with inadequate packaging, such as nylon nets, newspapers, plastic bags, and others. The association between inadequate packaging and egg exposure to air currents or contaminating agents makes a product highly susceptible to harmful microorganisms [
No fair passed the conformity test with regard to the place where the eggs were exposed. In fairs, the eggs were placed in inappropriate containers, in dirty stalls, and on the floor, and even hung on bars. The eggs were commercialized along with other products, such as fruits, vegetables, cereals, meat, and condiments. When different products are placed close to eggs, their odors are transmitted and cross-contamination may occur.
No purchase site placed eggs under refrigeration. The eggs were maintained at room temperature; most were exposed to sun light and heat when sold at town fair sites without any coverage. Pascoal et al. [
The above Decree, which deals with the consumption and preservation of eggs and inspection of their label, made certain information compulsory on the package. The expiry date on the packages was visible and complied with the norm only in the markets; the town fair sites did not mention it, making consumers’ choice difficult. Only four and three markets complied with the requirement of mandatory information on the package regarding product consumption and refrigeration, respectively. Not all market sites complied with these requirements; the percent of compliance was 22% and 16%, respectively (
Although this Decree [
Fourteen purchase sites in town fairs and one in the markets analyzed did not pass the conformity test for vectors and pests. These insects jeopardize food safety, and are instrumental in transmitting several harmful microorganisms [
Furthermore, food handlers in fairs failed to conform to the basic hygiene norms. There was lack of personal hygiene, and they were handling food and money simultaneously during the sale of products. Decree RDC n˚ 216/2004 specifies that no food handler should touch money or practice any activity, which may contaminate food [
Stringhini [
All bacteria have their ideal environment where they find optimal growth conditions. Temperature may have positive or negative effects on the growth of a bacterial population. Because of this, it is worth mentioning that several bacteria grow at ambient temperatures varying from 25˚C to 40˚C (mesophilic), some live at temperatures below 15˚C (compulsory psychrophiles), there are facultative psychrophiles, which exhibit optimal growth below 20˚C and finally the thermophiles, which has its growth rate of 50˚C to 60˚C. According to Braun & Fehlhaber [
There was a significant (p < 0.05) relationship between the total coliform counts and the variables “external dirt”, “external stains”, and “closeness to other products”, demonstrating a large number of non-conforming samples. No significant relationship was found for E. coli counts. Furthermore, no significant difference was detected with respect to the other variables.
The results of this study corroborate with those of previous studies [
The results of the present study reinforced that contaminated eggs are one of the common sources of infection through food products, increasing the chance of infections in consumers. While Brazilian Law necessitates the absence of Salmonella spp. in food products, these regulations are not uniformly enforced due to unofficial commerce of poultry products. In addition, the eggs sold at markets are often maintained at ambient temperature, which ranges from 27˚C - 35˚C throughout the year in Northeast Brazil. This temperature range is ideal for the proliferation of mesophilic bacteria, such as Salmonella spp. [
Eggshell cleaning is one of the most important steps to prevent microbiological contamination, because the major source of contamination of eggs is feces. However, even after being washed and sanitized, the eggs may be contaminated from external sources, which makes packaging, transportation, and storage critical factors for the quality of the final product [
The present observation analysis of egg selling sites revealed that they failed to comply of most the criteria established for egg commercialization and food handling, especially in town fairs. Although most samples proved to be microbiologically
Variables | TC | E. coli | ||||
---|---|---|---|---|---|---|
C | NC | p | C | NC | p | |
External dirt | <1.0 | 1.88 | 0.00 | <1.0 | 1.36 | 0.13 |
External stains | <1.0 | 1.85 | 0.00 | <1.0 | 1.35 | 0.13 |
Closeness to other products | <1.0 | 1.88 | 0.00 | <1.0 | 1.36 | 0.13 |
C, conformity with the law; NC, non-conformity with the law; Data were considered significant at p < 0.05.
adequate according to the current legislation, one sample from a public fair was contaminated with Salmonella sp. The consumption of food contaminated with this bacterium is harmful for the population.
Moreover, all the samples revealed the presence of microorganisms, with most of them being pathogenic, such as E. coli, indicating unsatisfactory hygienic conditions and fecal contamination. This shows that the commercialization process requires more attention and supervision by the concerned authorities to ensure that high-quality food reaches consumers and the risks caused by microorganisms are avoided.
We would like to thank the Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB Grant No. 23007.009264/2015-59) for funding the present study.
The authors declare no conflicts of interest regarding the publication of this paper.
da Silva Lima, W.K., Barros, L.S.S., da Silva, R.M., de Deus, T.B., das Virgens Lima, D. and dos Santos Silva, A. (2018) Hygienic and Sanitary Conditions of Eggs Commercialized in Town Fairs and Markets. Food and Nutrition Sciences, 9, 855-867. https://doi.org/10.4236/fns.2018.97064