Microbial Evaluation and Proximate Composition of Pastries Sold Within the University of Uyo Campuses

Microbiological evaluation and proximate composition of pastries sold within the University of Uyo Campuses were determined using standard microbiological and analytical techniques. A total of 28 pastries comprising buns, chin chin, cake and doughnut were bought from different locations within the three campuses (Main campus, Town campus and Annex campus). Microbiological analysis included total aerobic plate count, coliform count and fungal count. Moisture, crude protein, fat, crude fiber, ash and carbohydrate contents were determined by methods of Association of Official Analytical Chemist. Mean total aerobic plate count ranged from 1.5×10 to 4.7×10 cfu/g, fungal count ranged from 2.5×10 to 4.7×10 cfu/g while coliforms were not detected. Among the isolated organisms were potential foodborne pathogens and/or spoilage organisms: Staphylococcus aureus, Bacillus sp., Shigella sp., Salmonella sp., Aspergillus niger, Rhizopus sp. and Fusarium sp. There were high microbial population from Town and Annex campuses with buns having the highest level of microbial contamination. The percentage moisture, protein, fat, ash, fiber and carbohydrate content ranged from 6.13-16.10, 1.08-8.00, 0.40-16.00, 0.90-1.52, 0.50-2.15 and 60.00-85.98% respectively. These potential foodborne pathogens are of public health significance and require further monitoring. Original Research Article Ndubuisi-Nnaji and Ofon; JALSI, 7(3): 1-7, 2016; Article no.JALSI.28314 2


INTRODUCTION
In most part of the world, people depend on ready-to-eat (RTE) food also known as "Fast food" for a significant portion of their nutritional requirement. Pastry, a common type of fast food has become inevitable in our diets. In Nigeria, like other developing countries, the item is consumed by people of all age groups [1]. It is hawked and sold in every street, market place, social gathering, churches and university campuses across the country [2].
Pastries, locally called snacks, is seen in the western culture as a type of food that is not meant to be eaten as a main meal of the day like breakfast, lunch and dinner but rather to assuage a person's hunger between meals providing a brief supply of energy for the body [2]. It has been described by [3] as popular articles of diet because they are appetizing in appearance, convenient in form, nutritious in content giving pleasing fullness to the stomach when consumed.
The increase in consumption of pastries has been associated with changes in social patterns characterized by increased mobility and less family centered activities [4]. Furthermore, convenience and modern lifestyles, industrialization, economic down turn, quest for more wealth, materialism and the unavailability of time to prepare proper meal are also responsible for the increased patronage of pastries [5]. Worthy of mention is the fact that the increased consumption and sales of pastries have provided employment and contracts to the food vendors [6,7]. Since pastries are consumed on the go, it is obviously a favourite for both students and staff of most universities. The University of Uyo for instance, operates many campuses within Akwa Ibom State and with a student and staff population of approximately 18,724 and 1,406 respectively it is expected that a high patronage and consumption of these snacks would be recorded, especially during business hours.
The major problem associated with pastry is the frequent incidence of contamination [2,8]. Due to their composition and methods of preparation involving extensive handling, they are usually prone to contamination from water, air, storage, distribution facilities and human activities (food handlers and vendors). Like other processed foods, pastries are subject to physical, chemical and microbial spoilage by organisms such as Escherichia coli, Salmonella sp., Clostridium sp., Staphylococcus aureus, Listeria sp., Bacillus sp. and moulds of several genera such as hizopus, Aspergillus and Penicillium [4,9,10]. Contamination with fungi of the genera Mucor, Eurotium, Aspergillus, Monilla, Fusarium and Rhizopus have been linked to the short term shelf life of many pastries [11].
The implications of consuming contaminated pastry is the risk associated with ingestion of microbial cells, toxins and mycotoxins produced by microorganisms present in the food. Food borne illness is a major international health problem with attendant economic nosedive [12]. Data on issues of food borne diseases are documented worldwide [13].
These diseases can be checked or prevented if proper personal hygiene such as maintaining clean processing environment/equipment as well as wearing clean apron/apparel and hand gloves at point of sales is adopted. This research was therefore aimed at evaluating the microbiological quality and the proximate composition of pastries sold within the University of Uyo campuses, with a view to: Enumerating the microbial isolates from the pastry samples, characterizing and identifying the isolates as well as determining the proximate composition of these pastries in relation to their nutritional benefits.

Sample Collection
Four (4) samples each of fresh doughnut, buns, cake and chin-chin (a small Nigerian cookie-like snack made from fried wheat flour dough containing eggs, sugar and sometimes milk) were purchased from different vendors at each campus. All the samples were aseptically collected separately into sterile polyethylene bags with proper labelling. A total of forty eight (48) samples were collected from the three (3) different campuses. Microbiological analysis was carried out in the Department of Microbiology laboratory while the proximate food analysis was carried out at Food Science and Technology laboratory both in the University of Uyo, Uyo, Akwa Ibom State, Nigeria.

Sample Analysis
For microbiological analysis, samples of each type of pastry were bulked and homogenized. Ten (10) g portion of each homogenate was weighed and transferred into 90 ml of sterile water blank. This was mixed vigorously and 10 ml of the suspension was transferred into another dilution blank and serially diluted.
One (1) ml aliquot (10 -4 and 10 -5 ) was plated in triplicates using pour plate technique on Nutrient agar for total aerobic bacterial counts (TABC), MacConkey agar for total coliform counts (TCC), Salmonella-Shigella agar for Salmonella and Shigella counts (SSC) and Sabouraud Dextrose agar for total fungal counts (TFC). A four-way streak on Eosine methylene blue agar plate from the 10 1 dilution was also carried out for E. coli detection. The bacterial plates were incubated at 37±2°C for 18-24 hours while fungi plates were incubated at room temperature (28±2°C) for 72-120 hours and observed for growth.
The proximate composition was determined according to the methods described by [14]. This included determination of crude protein (total nitrogen), crude fibre, crude lipid, moisture, ash, nitrogen-free extract and carbohydrate content. The moisture content was determined by heating 2.0 g of each pastry sample to a constant weight at 105°C in an oven. For crude protein (% total nitrogen × 6.25), this was performed by Kjeldahl methods using 2.0 g of each samples. The ash content was determined by incinerating 1.5 g of each sample at 550°C for 5 to 8 hours. The crude fibre was determined by digesting 2.0 g of each sample with H 2 SO 4 and NaOH and subsequently incinerating at 550°C in a muffled furnace for 5 h. Crude lipid was obtained by exhaustively extracting 10 g of each sample in Soxhlet apparatus using N-hexane as the extractant. Percentage carbohydrate was estimated using the mathematical expression: 100 -(% moisture, ash, fibre, lipid, protein).

Enumeration and Identification of Isolates
The isolates were enumerated and purified by subculturing. Characterization was based on colonial morphology, cultural characteristics, staining and biochemical reactions. The bacterial isolates were identified using Bergey's Manual of Determinative Bacteriology [15] while the fungal isolates were characterized based on their colonial and cellular morphology and identified as described by [16].

RESULTS AND DISCUSSION
Although coliforms were not detected in the study, the microbiological status of the pastry samples based on mean total aerobic plate count revealed that all samples were contaminated (Fig. 1). Specifically, buns (4.7×10 4 ) and doughnut (2.5×10 4 ) had higher levels of contamination when compared with other samples. This is particularly unsatisfactory as contained in the Public health laboratory standard [17,18,19] of the Advisory committee for food and dairy (ACFD) products which stipulates 10 3 to less than 10 4 cfu/g for aerobic plate count. Similarly, buns had the highest fungal load (Fig.  2) with mean count ranging from 2.5×10 3 to 4.7×10 4 cfu/g in the three campuses under investigation. Notwithstanding, the highest level of microbial contamination was observed in annex campus. The trend observed in this study corroborates earlier works [6,7] and may in part be attributed to the high human and vehicular movement in these campuses. On the other hand, the comparatively high microbial loads in buns and doughnut may be due to the proximate composition (moisture content) of these samples as well as other ingredient used in their preparation. Studies [4,8,20] have indicated that these ingredients serve as media for the growth and proliferation of microorganisms in food. However, high temperature involved in cake preparation, may have accounted for the relatively low microbial load in this product. The organisms isolated from this study confirms the findings of previous researchers [21,22] and they included Bacillus sp., Staphylococcus aureus, Salmonella sp., Shigella sp., Aspergillus sp., Fusarium sp. and Rhizopus sp (Table 1). S. aureus was predominant in all the samples. These organisms have been implicated with serious foodborne illness/diseases and are also known to cause food spoilage. S. aureus which is a normal flora of the human skin produces a heat stable enterotoxin in food [23] and upon ingestion of such contaminated food presents symptoms ranging from abdominal cramps, nausea, vomiting, prostration to diarrheoa and subsequent dehydration. Despite the heat treatment employed during preparation of pastries, the presence of pathogens is evidently a consequence of post-treatment contamination as their preparation involves extensive handling. In addition, exposure of prepared pastries to surrounding air as well as packaging materials [24,25] are possible sources of microbial contamination. This underscores the need to implement and enforce safety guidelines for pastries in Nigeria.

CONCLUSION
Based on the public health laboratory standard of the Advisory committee for food and dairy (ACFD) products guidelines, the microbiological status of some of the pastry samples under evaluation were within acceptable statutory limits (10 3 to less than 10 4 cfu/g for aerobic plate count). There is however the need to ensure inspection and maintenance of standard (good manufacturing practices) in order to reduce the risk and/or outbreak of foodborne infections/ illnesses.