Effect of four local vegetable leaves on the protein and microbial content of smoked and dried beef

Abstract

Raw beef was subjected to Chemical and microbial analysis, then treated with either extracts or powders of four local vegetable leaves namely “Utazi” Gongronema vatifolia. “Uziza” Piper guineesis “Onugbu” Vernonia amygdalina and “Nchuanwu” Ocimum gratissimum at three different concentrations. The treated raw beef was smoked and some other were dried for 3 hours respectively, then stored unpacked. Two control samples; one having no treatment and the other with 0.02% Na₂S₂O₅ were run. The processed beef samples were microbially and chemically analysed after treatment and during storage. Beef treated with leaves extracts revealed Staphylococcus aureus after 28 days of storage, while 49 days for those treated with powdered leaves revealed lower microbial load (staphylococcus aureus). Meat with Na₂S₂O₅ showed a reduced microbial load compared to untreated samples. Samples treated with “Onugbu” extract and powdered leaves showed the lowest microbial counts followed by “Nchuanwu”, “Utazi” and “Uziza” in that order. Dried meat samples showed lower microbial load than smoked samples. Cultured plates when analyzed revealed growth of Fusarium spp, Penicillium camemberti, Botrytis cihera, Candida albican, Mucor spp and Aspergillus niger. The statistical analysis carried out showed that protein was significantly different (p<0:05) at various level of concentration, with “Nchuanwu” and “Uziza” treated samples the highest. Sensory scores at (p<0.05) showed that treatment effect on the organoleptic qualities have significant difference.

Keywords: beef, leaves, protein, microbes, preservation

Nigerian Food Journal Vol. 23 2005: 74-84